Primary cutaneous follicular lymphoma: a clinicopathologic and molecular study of 16 cases in support of a distinct entity

Primary cutaneous B-cell lymphomas displaying a prominent follicular growth pattern are rare and remain poorly defined, particularly in terms of the frequency of detection of t(14;18) and whether or not, as a group, they represent an entity distinct from follicular lymphoma arising in lymph nodes. The morphologic, immunophenotypic, and clinical features of 16 cases of primary cutaneous follicular lymphoma, identified during a review of all PCBCL in the Scotland and Newcastle Lymphoma Group database, were studied and the number of cases harboring t(14;18) assessed by polymerase chain reaction using primers to the major breakpoint cluster region. Comparisons were made with stage I follicular lymphoma arising in lymph nodes and follicular lymphoma secondarily involving the skin. All cases of primary cutaneous follicular lymphoma had undergone thorough staging, including physical examination and CT scans of chest and abdomen, with 15 of 16 cases also having bone marrow aspiration and/or trephine performed. The morphology and immunophenotype of the lesions were similar to that expected in lymph nodes. All cases displayed a follicular architecture complete with follicular dendritic cell networks and comprised an admixture of CD10 and/or bcl-6-positive neoplastic centrocytes and centroblasts with 13 of 16 cases also expressing bcl-2 protein. None harbored t(14;18), a significantly different finding compared with cases of stage I nodal follicular lymphoma (p <0.001) and secondary cutaneous follicular lymphoma (p <0.039). Relapses occurred in five of 15 patients with a median time to first relapse of 20 months (range 1-73 months; mean 27.2 months). These were multiple in two patients and involved extracutaneous sites in two patients. The propensity for relapse was similar to that in a comparative cohort of stage I nodal follicular lymphoma, but the group of primary cutaneous follicular lymphoma were significantly more likely to attain complete remission; all cases of primary cutaneous follicular lymphoma were in complete remission when last seen compared with 49 of 87 patients with stage I nodal follicular lymphoma (p <0.005). No lymphoma-related deaths were encountered in 15 cases with a mean follow-up >60 months (range 5-119 months). These results support the concept of a subtype of follicular lymphoma lacking t(14;18) involving the major breakpoint cluster region, and with a propensity to arise in the skin. Despite a high relapse rate patients with primary cutaneous follicular lymphoma are more likely to achieve complete remission and may ultimately have a more favorable long-term prognosis than those with equivalent nodal disease.     

Neoplastic cells do not carry bcl2-JH rearrangements detected in a subset of primary cutaneous follicle center B-cell lymphomas

Whether primary cutaneous follicular lymphoma (PCFL) may or not represent a cutaneous equivalent to nodal follicular lymphoma (FL) is not determined. We have therefore investigated a series of PCFL to determine if tumoral cells carry or not the t(14;18)(q32;q21) translocation, a cytogenetic hallmark of nodal FL. Thirty cases of PFCL were selected according to the criteria of both the European Organisation for Research and Treatment of Cancer and the World Health Organization with 21 cases classified as grade 1 or 2 and 9 cases as grade 3. First, cutaneous tumors were studied by PCR for the amplification of bcl-2/JH rearrangements and by interphase fluorescence in situ hybridization using a dual color probe spanning t(14;18) breakpoints. Second, we tried to determine the origin of bcl2-JH-positive cells by a parallel bcl2-JH and immunoglobulin heavy chain gene amplification of blood mononuclear cells DNA and of DNA extracted from single microdissected B cells. Bcl2-JH rearrangements were amplified by PCR in skin of 9 of 30 (30%) patients with a similar-sized bcl2-JH rearrangement detected in the blood of 7 of these 9 cases. No t(14;18) breakpoint was detected by interphase fluorescence in situ hybridization analysis of 11 bcl2-JH-negative and 5 bcl2-JH-positive PCFL in contrast with its detection in the secondary cutaneous FL and in the nodal FL cases. Single-cell/multigene analysis showed that no single monoclonal B cells of PCFL carried the bcl2-JH rearrangement. Bystander or nontumoral t(14;18)+ B cells emigrating from blood may account for the detection of bcl2-JH rearrangements within PCFL material. Our study also underlines the diagnostic value of interphase fluorescence in situ hybridization to discriminate between t(14;18)-negative PCFL and extracutaneous FL involving the skin.     

Primary and secondary cutaneous diffuse large B-cell lymphomas: a multiparameter analysis of 25 cases including fluorescence in situ hybridization for t(14;18) translocation

Although primary cutaneous diffuse large B-cell lymphomas (DLBCLs) except for those of the leg are grouped together with primary cutaneous follicle center cell lymphoma in the European Organization for Research and Treatment of Cancer classification of primary cutaneous lymphomas, they typically lack the usual phenotypic profile of follicular lymphoma. Whether they are truly of follicular center cell origin, have a molecular pathogenesis similar to nodal follicular lymphoma, or have any biologic features that distinguish them from secondary DLBCL involving skin remains uncertain. To address these issues, a retrospective multiparameter study of 25 patients including clinical, histologic, immunophenotypic, and cytogenetic analyses was performed. A classic CD10+, bcl-6+ follicular center cell profile was found in 10 (40%) cutaneous DLBCL (2 of 11 primary, 5 of 8 secondary, 3 of 6 unclassified) with bcl-2 expression seen only in the nonprimary cases. Of the remaining cases, 14 cases (56%) were CD10-, bcl-6+, bcl-2+/- (9 primary) and one case (4%) was CD10-, bcl-6-, bcl-2+ (0 primary). Fluorescence in situ hybridization analysis showed a t(14;18) in 0 of 9 primary and 3 of 5 secondary cases. Primary cases were frequently found in the head/neck region, whereas secondary cases were more common on the trunk and extremities. Patients with primary disease were all alive, usually having received only local therapy, at a median follow-up of 19 months. Most secondary cases were treated with chemotherapy with only one untreated patient dead of disease at a median follow-up of 5 months. Primary cutaneous DLBCLs therefore appear to be distinctive as they have fewer features of follicular lymphoma than do secondary cases. Nevertheless, some appear to be of follicular center cell origin, even though they probably have a different molecular pathogenesis than most nodal follicular lymphomas.     

Molecular cytogenetic evidence of t(14;18)(IGH;BCL2) in a substantial proportion of primary cutaneous follicle center lymphomas

In contrast to nodal follicular lymphoma, limited data exist on genetic changes in primary cutaneous follicular lymphoma (primary cutaneous follicle center lymphoma according to WHO-EORTC). The detection rate of the BCL2 rearrangement, representing the characteristic t(14;18)(q32;q21) underlying follicular lymphoma, by polymerase chain reaction (PCR) has been reported to vary over a wide range (0%-41%), and only a few cases have been studied by molecular cytogenetic techniques such as fluorescence in situ hybridization (FISH). In this study, 27 primary cutaneous follicle center lymphomas were analyzed by FISH and the results compared with those obtained by PCR. FISH demonstrated translocations affecting the immunoglobulin heavy chain locus (IGH) in 14 of 27 cases (52%): a t(14;18)(q32;q21) involving BCL2 was found in 11 cases (41%), a t(3;14)(q27;q32) affecting BCL6 in 2 cases (7%), and in 1 case the partner gene of IGH could not be identified. Interestingly, PCR did not detect BCL2 rearrangement in any case. These data suggest that the t(14;18)(q32;q21) frequently occurs in primary cutaneous follicular lymphoma. The reason(s) why BCL2 rearrangements escape the detection by PCR is (are) not clear but could be due to BCL2 mutations, breakpoints outside the amplified DNA, or a high load of somatic mutations.     

Large B-cell lymphoma presenting in the spleen: identification of different clinicopathologic conditions

Only a few series of splenic large B-cell lymphoma have been previously reported, including limited immunophenotypic studies and clinical data. Here we review the clinical data, morphology, and immunophenotype of series of 33 cases of large B-cell lymphoma presenting in the spleen. Three main groups of tumors are identified. Group A was characterized by macronodular tumors (20 cases), with predominantly stage I disease and a favorable clinical outcome. All cases were bcl6 positive. Group B was characterized by a micronodular pattern (nine cases), including a subset with T-cell-rich B-cell lymphoma features. Most of the patients in this group were diagnosed at advanced clinical stages and died of the disease. All cases were bcl6 positive. Group C was characterized by diffuse red pulp infiltration (four cases) and advanced clinical stages and showed an aggressive behavior. All but one case were bcl6 positive. The results of this series define a characteristic type of large B-cell lymphoma presenting in the spleen as a tumoral mass, associated with a relatively favorable clinical course. Additionally, they provide evidence that clinical presentation as a tumor confined to the spleen and the hilar lymph nodes is associated with lower aggressivity.     

Clinicopathologic, immunophenotypic, and molecular cytogenetic fluorescence in situ hybridization analysis of primary and secondary cutaneous follicular lymphomas

Although primary cutaneous follicular lymphoma (FL) is considered a distinct variant of FL in the World Health Organization classification ("cutaneous follicle center lymphoma"), its biologic relationship to nodal FL remains controversial. The clinical, morphologic, immunophenotypic, and molecular cytogenetic features of 17 patients with primary cutaneous FL were studied and compared with 16 patients with secondary cutaneous FL. The head and neck region was the most frequent site at initial skin presentation in both the primary and secondary cases. Among the primary cases, 29% of the 31 biopsies were grade 1, 48% grade 2, 13% grade 3, and 10% grade 3 with diffuse large B-cell (DLBCL) areas. Among the secondary cases, 38% of the 29 skin biopsies were grade 1, 45% grade 2, 3% grade 3, and 7% grade 3 with DLBCL areas with two not evaluable. A floral-like pattern was observed in 32% of primary FL but only 5% of secondary cases. Histologic progression was found in 21% of patients. CD10 expression was demonstrated in 90% (27 of 30) of primary cases and 96% (22 of 23) of secondary cases. Bcl-6 was expressed in all cases tested. Bcl-2 expression was detected in 57% (17 of 30) of the primary cases (100% of grade 1, 43% of grade 2, 40% of grade 3), whereas all secondary cases were bcl-2 positive (P=0.0002). The t(14;18) translocation was identified by interphase fluorescence in situ hybridization (FISH) in biopsies from 31% (4 of 13) of the patients with primary FL compared with 77% (10 of 13) of those with secondary lymphoma (P <0.05). Seven of the 17 (41%) patients with primary disease had cutaneous relapse, including 1 who also developed nodal disease. Bcl-2 positivity was seen in 4 of these 7 patients. Eight of the 16 (50%) patients with secondary FL had cutaneous relapse. Primary and secondary cutaneous FL share many clinical and phenotypic features, but primary cases may have some distinctive morphologic features, more frequently lack bcl-2 protein, and often lack the t(14;18) translocation. These findings suggest that primary cutaneous FL are distinctive and often but not always have a pathogenesis different from most of nodal and secondary cutaneous FL.     

BCL-2 is consistently expressed in hyperplastic marginal zones of the spleen,abdominal lymph nodes,and ileal lymphoid tissue

BCL-2 is an antiapoptotic protein overexpressed in follicular lymphomas, principally as a result of the t(14;18)(q32;q21), and useful in distinguishing follicular lymphoma (usually BCL-2 positive) from follicular hyperplasia (BCL-2 negative). BCL-2 is also overexpressed in other lymphoma types without the t(14;18), including marginal zone B-cell lymphoma, because of other, poorly understood mechanisms. It has been suggested that BCL-2 immunoreactivity can distinguish between malignant (BCL-2 positive) and reactive (BCL-2 negative) marginal zone B cells. In this study, we evaluated 26 spleen, 10 abdominal lymph node, and 3 ileum specimens with marginal zone B-cell hyperplasia for BCL-2 expression immunohistochemically. We also analyzed these cases using polymerase chain reaction methods to evaluate for the presence of clonal rearrangements of the immunoglobulin heavy chain gene (IgH) using consensus V FRIII and J region primers, and the t(14;18) involving both the major breakpoint and the minor cluster regions of the bcl-2 gene. All (100%) cases of splenic, abdominal lymph node, and ileal marginal zone hyperplasia displayed strong BCL-2 reactivity in the marginal zone B cells. In all cases analyzed, IgH polymerase chain reaction demonstrated a polyclonal pattern, and bcl-2/JH DNA fusion sequences were not detected. Our results indicate that BCL-2 is consistently expressed by reactive marginal zone B cells of the spleen, abdominal lymph nodes, and ileal lymphoid tissue and should not be used as a criterion for discriminating between benign and malignant marginal zone B-cell proliferations involving these sites.     

Cutaneous b-cell lymphomas of follicular and marginal zone types: use of Bcl-6, CD10, Bcl-2, and CD21 in differential diagnosis and classification

Cutaneous follicular lymphomas (FLs) and cutaneous B-cell lymphomas of extranodal marginal zone (MZL)/mucosal-associated lymphoid tissue (MALT) type may have morphologic overlap, despite the fact that they are thought to be of distinct derivation (germinal center vs. postgerminal center). The problem is compounded by the reported absence of bcl-2 expression by many cutaneous FLs, leading to speculation that cutaneous FL may be unrelated to nodal FL. The authors analyzed the expression of the germinal center-associated antigens bcl-6 and CD10 and of bcl-2 in 18 cutaneous B-cell lymphomas (10 FLs and eight MZLs), in relationship to CD21+ follicular structures, to clarify the relationship of nodal to cutaneous FLs and to explore the value of these antigens in differential diagnosis. The authors studied 10 cutaneous FLs (seven primary and three secondary) and eight MZLs (six primary and two secondary). The FLs (found in six men and four women age 45-75 years) involved the trunk (n = 3) and scalp, face and neck (n = 7). The MZLs (found in five women and three men age 34-81 years) involved the trunk (n = 4), face and neck (n = 2), and arm (n = 2). Immunostaining for CD21, bcl-6, CD10, and bcl-2 allowed the delineation of compartments within the tumors and yielded distinct patterns of staining in FL and MZL. In both follicular and interfollicular/diffuse areas of FL the neoplastic cells were bcl-6+ (10 of 10), often CD10+ (seven of 10, four of seven primary), and bcl-2+ (nine of 10, six of seven primary). Only three of seven cases (one of five primary) had bcl-2 rearrangement detectable by polymerase chain reaction. In the MZLs, the neoplastic B-cells were bcl-6-, CD10-, and bcl-2+ (eight of eight). Three patterns of CD21+ follicles were identified in MZL: reactive germinal centers, uniformly bcl-6+, CD10+, and bcl-2- (five of eight MZLs); colonized follicles, both bcl-6-, bcl-2+, and L26+ cells, and bcl-6+ and bcl-2- cells (five of eight MZLs); and expanded/colonized follicular dendritic cell meshworks, bcl-6- and bcl-2+ B cells with rare residual bcl-6+ and bcl-2- cells (four of eight MZLs). The authors conclude that cutaneous FLs express bcl-6 uniformly, usually express CD10 and bcl-2, and have a follicular pattern similar to nodal FL and consistent with a germinal center origin. The immunophenotype of cutaneous FL is distinct from that of cutaneous MZL, which is negative for bcl-6 and CD10. Colonized follicles in MZL, identified by CD21+ follicular dendritic cell meshworks, contained numerous bcl-6- and bcl-2+ B cells, and were readily distinguished from neoplastic follicles in FL. Conversely, CD21- interfollicular and diffuse areas in FLs contained bcl-6+ and CD10+ cells, which were not seen in diffuse areas of MZLs. Thus, the combination of bcl-2, bcl-6, and CD21 staining is useful for the distinction of cutaneous MZL from cutaneous FL.     

Clinical implications of progressive transformation of germinal centers

Fifty patients whose lymph node biopsies showed reactive follicular hyperplasia with the presence of progressive transformation of germinal centers were evaluated for current status of health, prior or subsequent development of Hodgkin's disease, and etiology of the lymph node hyperplasia. Histologically, on a background of reactive follicular hyperplasia, the nodes contained one or more germinal centers showing progressive transformation. These were three to four times the diameter of the other germinal centers and composed predominantly of small, round lymphocytes admixed with scattered immunoblasts and occasional benign histiocytes. Clinically, the majority of these patients were young males presenting with an asymptomatic solitary enlarged lymph node. fifteen had prior Hodgkin's disease. Five had concurrent progressive transformation of germinal centers and lymphocytic predominance Hodgkin's disease (two of these also had a subsequent biopsy showing only progressive transformation of germinal centers). All are currently free of Hodgkin's disease at 1-21 years. The largest group of 31 patients had no prior or subsequent Hodgkin's disease. One of the 50 developed multiple myeloma. Recognition of this phenomenon is important so that it will not be misconstrued as recurrent Hodgkin's disease, as de novo Hodgkin's disease, or as follicular lymphoma, which occurred in 12 (24%) of the cases.     

Lymphocyte predominance Hodgkin's disease: the use of bcl-6 and CD57 in diagnosis and differential diagnosis

Distinction of lymphocyte predominance Hodgkin's disease (LPHD) from other forms of lymphoma often requires immunohistochemistry (IHC). Most previously published recommended panels include markers to define the large neoplastic cells (for example, CD20, J chain, CD45) as well as the non-neoplastic background cells (CD21, CD45RO, CD57, TiA 1). In the present study we examine the practical use of a double IHC method designed to look simultaneously at two germinal center specific cell types: bcl6+ cells and [bc16+, CD57+] co-positive cells. All 10 nodular LPHD had bcl6+ large cells and numerous CD57+ small background cells, including [bcl6+CD57+] cells in rosettes. One case of LPHD with large cell transformation contained numerous bcl6+ large cells both singly (in areas of typical LPHD) and in sheets (in foci of large cell transformation), many CD57+ small cells but few [bcl6+CD57+] co-positive cells and no rosettes. In none of the five cases of florid progressive transformation of germinal centers were true rosettes seen, although all contained variable numbers of bcl6+ large cells and CD57+ cells. Lymphocyte-rich classic Hodgkin's disease LRCHD cases were notable for bcl6 reactivity in Reed-Sternberg cells in all cases, numerous background small bcl6+ lymphocytes, and rare CD57+ cells. Two phenotypic profiles were associated with the 10 cases of T cell-rich B cell large cell lymphoma (TCRBCL). In the first, group "A," six of six cases had bc16- large cells and few CD57+ small cells, and none had significant numbers of [bcl6+, CD57+] co-positive cells. In the second, group "B," four of four cases had bcl6+ large cells with numerous CD57+ and [bcl6+, CD57+] co-positive cells. These findings not only show that LPHD can be distinguished from its morphologic mimics through identification of specific germinal center cell types, but also identifies a second group of TCRBCL (group "B") whose phenotype suggests it might be an architectural variant of nodular LPHD.     

The role of the perifollicular sinus in determining the complex immunoarchitecture of angioimmunoblastic T-cell lymphoma

The growth of angioimmunoblastic T-cell lymphoma (AIL) in lymph node often produces complex patterns of neoplastic T cells and nonneoplastic B cells that complicate diagnosis. To understand better how these different patterns of B-cell expansion arise, we compared the microanatomic localization of B cells and T cells within the follicular, paracortical, and sinusoidal compartments in 30 patients with AIL (including 10 with multiple sequential samples) with that seen in 33 cases of other types of T-cell lymphoma. With early or partial nodal involvement in AIL, germinal center B-cell expansions were relatively undisturbed and often associated with a variably distended D2-40+ CD31+ perifollicular sinus that surrounded most of the follicular compartment. Identifiable tumor T cells resided mostly in the paracortex. In later stages of AIL with more complete nodal effacement, bcl-6+ follicular B-cell proliferations shifted to distorted FDC networks arrayed along patent trabecular sinuses and were more intermixed with tumor T cells. In both AIL and other T-cell lymphomas, the density and locations of follicular B cells as well as bcl-6-negative monocytoid B cells were largely related to the patency of adjacent sinuses, except in Epstein-Barr virus (EBV)+ and histiocyte-rich B-cell proliferations, which arose in paracortical locations. The prominence of the perifollicular sinus in early stages of AIL resembled that seen in reactive lymphadenitis during conditions of lymphatic engorgement and implicates cytokines within lymph fluid in maintaining both the normal and altered germinal center reactions. Patterns of sinus drainage largely explain the useful changes in B-cell distribution that occur in nodal T-cell lymphomas and represent an important tool in classification and diagnosis of these tumors.     

The varied histopathology of lymphadenopathy in the homosexual male

We review the clinical features and histopathologic changes observed in 69 cases of lymphadenopathy in homosexual men. The most common pattern seen was that of florid reactive follicular hyperplasia (43 cases). A peculiar and distinctive lysis of the germinal centers, a phenomenon we have termed "follicle lysis," was noted in 25 cases. Eighteen of these lymph nodes also contained sinusal collections of "monocytoid" cells and neutrophils and six showed focal dermatopathic changes. Seven cases were characterized by a lymphocyte-depleted pattern with only occasional regressively transformed germinal centers. Nine patients were found to have involvement of their lymph nodes by Kaposi's sarcoma; malignant lymphomas were encountered in 10 patients (eight with Hodgkin's disease and two with non-Hodgkin's lymphomas). Polykaryocytes (multinucleated giant cells) were observed in germinal centers or interfollicular areas within the lymph nodes of four patients. Limited clinical follow-up was available but the lymphocyte-depleted group appeared to have a more aggressive clinical course (three patients in this group developed pneumocystis pneumonia, two had mycobacterial infections and one cutaneous Kaposi's sarcoma). The diverse nature of these findings and the potential for treatment of certain patients (i.e., those with malignant lymphomas and mycobacterial infections) underlines the importance of lymph node biopsy in all cases of unexplained lymphadenopathy in homosexuals and other individuals susceptible to the acquired immunodeficiency syndrome (AIDS). The histopathologic findings may also serve to identify a subgroup of these patients at increased risk to develop more severe AIDS-related complications.     

The skin overlying the sentinel lymph node: a full thickness skin graft donor site after local excision for cutaneous melanoma

Wound defects resulting from wide local excision for cutaneous melanoma, can require the use of skin graft for closure. Harvesting the skin graft can result in an additional morbidity. The increasing use of sentinel lymph node biopsy in cutaneous melanoma allows us the development of an alternative technique for obtaining donor skin. This method utilizes the skin overlying the sentinel lymph node as the skin graft donor site. Sixteen patients with cutaneous melanoma over than 1 mm of Breslow index, underwent wide local excision with sentinel lymph node biopsy and full thickness skin graft harvested from the node biopsy site. After a median follow-up of 18 months, there were no graft failure, one case of lymph swelling was relieved in the donor site. There were no melanoma recurrence and no metastasis. One case of in transit metastasis was treated by local excision and suture. In cases were primary closure is not feasible or cosmetically unfavourable, the use of the sentinel lymph node site as a skin graft donor, provides an alternative technique sparing the patient an additional skin graft donor site defect.     

Cutaneous follicular lymphoma

Fifteen cases of cutaneous follicular lymphoma were evaluated clinically, histologically, and immunologically. Nine of the patients presented with skin disease alone, which showed a predilection for the scalp and forehead. The six remaining cases had either concurrent or secondary cutaneous involvement. All of the cases had a nodular configuration which was evident histologically or immunologically. In many cases, the diagnostic microscopic fields were in the deep dermis or subcutis, with nonspecific inflammation in the superficial dermis. The cases consisted of five small cleaved, seven mixed, and three large cell follicular lymphomas. A senior dermatopathologist diagnosed four of the 15 cases as benign, indicating the difficulty of diagnosis by morphology alone when the biopsy is small or the inflammatory component is prominent. This underscores the importance of large, deep biopsies for accurate histologic diagnosis. Immunological studies confirmed the B cell lineage of these lesions. An unexpectedly high proportion of immunoglobulin-negative cases (eight cases) was found, especially among the primary cutaneous follicular lymphomas (six of nine cases). Immunoglobulin-expressing cases exhibited monotypic immunoglobulin light-chain staining of tumor cells. In all cases, the dendritic reticulum cell network within lymphoma follicles lacked the polytypic immunoglobulin complexes characteristic of reactive follicles. As described previously for follicular lymphomas in lymph nodes, many cases exhibited polytypic follicular mantle zones similar to reactive follicles. The low-grade nature of these lymphomas was supported by clinical follow-up. We conclude that given adequate sampling, cutaneous follicular lymphomas can usually be diagnosed by histologic criteria similar to those used for lymph nodes; however, immunohistologic studies are an important adjunct.     

Primary cutaneous CD4+ small/medium-sized pleomorphic T-cell lymphoma expresses follicular T-cell markers

Cutaneous CD4 small/medium-sized pleomorphic T-cell lymphoma (CSTCL) is a cutaneous T-cell lymphoma defined by a predominance of small-to-medium-sized CD4 pleomorphic T cells, with a favorable clinical course. Cases are also characterized by the presence of a rich infiltrate of reactive B cells. Recently, it has been reported that follicular helper T cells (TFH cells) display a distinct gene expression profile, positive for PD-1, CXCL13, and BCL-6. We report for the first time the expression of PD-1 and other TFH cell markers in CSTCLs and discuss its biologic significance. Sixteen CSTCLs were included in this study, and also 20 reactive inflammatory conditions, 10 primary cutaneous marginal zone, 10 follicular center lymphomas, and 5 primary CD30 cutaneous lymphomas. They were immunohistochemically analyzed for a large panel of markers. Double immunoperoxidase labeling of paraffin sections was performed for PD-1, OCT-2, and BCL-6. Clonal Ig and T-cell receptor rearrangements and Epstein-Barr virus-encoded RNA expression were also evaluated. Morphologic and clinical data were reviewed. Histologic examination showed a dense polymorphic lymphoid infiltrate throughout the dermis. Atypical large CD4 cells were positive for PD-1, CXCL13, and BCL-6 in all cases, and were attached in small clusters, or formed rosettes around CD30/OCT-2+ B blast cells. Epstein-Barr virus was not apparent in any of the cases. A dominant T-cell clone was identified in 14 cases, whereas polymerase chain reaction IgH gene rearrangement studies showed that all cases were polyclonal. None of the patients had lymphadenopathy or showed any evidence of systemic disease, nor did they have any previous history of mycosis fungoides or drug reactions. FTH cell markers are not exclusive to angioimmunoblastic lymphadenopathy but may also be seen in neoplastic cells of CSTCLs. Moreover, these findings suggest that B-cell stimulation by FTH could also take place in some cutaneous T-cell lymphomas.     

Primary follicular lymphoma of the testis and epididymis in adults

Primary testicular lymphomas typically occur in patients over 60 years of age. Most are diffuse large B-cell lymphomas with frequent dissemination and a poor prognosis. Primary follicular lymphoma of the adult testis has not been well characterized. However, a small number of primary testicular follicular lymphomas have recently been described in children. These showed stage 1E disease, a lack of BCL2 gene rearrangement and Bcl-2 protein expression, and a good clinical outcome. Here, we describe 5 cases of primary follicular lymphoma of the testis and epididymis in adults. These presented as unilateral testicular masses 12 to 40 mm in diameter and were characterized histologically by small neoplastic follicles in a sclerotic background. The neoplastic cells expressed CD10 and Bcl-6, but not Bcl-2 and lacked t(14;18)(q32;q21)/IGH-BCL2 and BCL6 gene rearrangements. Four of the five patients were 35 years old or younger, and 4 presented with stage 1EA disease. Although follow-up is 12 months or less in 2 of the 5 patients, to date each has followed an indolent clinical course. These features are different from those of most adult nodal follicular lymphomas but are very similar to those of the pediatric primary testicular follicular lymphomas. Together, the pediatric and adult cases represent a discrete clinicopathologic entity of t(14;18)(q32;q21)/IGH-BCL2-negative primary follicular lymphoma of the testis and epididymis, which typically present as clinically indolent localized disease in young males and should be distinguished from the diffuse large B-cell lymphoma more frequently seen in the testes of older adults.     

Primary cutaneous large B-cell lymphoma: the relation between morphology, clinical presentation, immunohistochemical markers, and survival

The histogenesis, morphology, immunophenotype, and clinical behavior of cutaneous large B-cell lymphomas (CLBCL) are largely a matter of controversy. We performed an investigation to determine whether CLBCL have features that differentiate them from other large B-cell lymphomas and whether CLBCL is itself a heterogeneous group. To this end, we reviewed the main characteristics of a series of 32 cases of LBCL found in the skin. We reviewed the clinical findings and paraffin sections of the tumors from these 32 patients. The immunohistochemical study performed included p53, MIB1, Bcl2, Bcl6, and CD10 markers. We carried out statistical analysis of these data (univariate and multivariate), seeking an association between the features of the tumors and clinical outcome, as defined by failure-free survival time. Only one patient died as a consequence of the lymphoma. Nevertheless, the accumulated probability of survival without failure at 48 months was 0.46. The number, type, and localization of the lesions were not associated with variations in either survival or failure-free survival. The expression of p53 was negative in this group of CLBCL, whereas Bcl-2 expression or localization in the lower leg did not relate to any other significant feature. Histologic examination of the cases disclosed three different groups: Grade III follicular lymphomas (FLs), monomorphous large B-cell lymphomas (LBCL type I), and LBCL with an admixed component of small B-lymphocytes (LBCL type II). Grade III FL (11 cases) tended to be found in the head and neck and showed CD10 expression in a majority of cases. A higher probability of lymph node relapses was associated with cases located in the head and neck and with CD10+ tumors. Cutaneous large B-cell lymphomas are indolent tumors, but follow an insidious course. Our data support the interpretation that CLBCL is a heterogeneous condition; comprises some LBCL derived from CD10+ germinal center cells which manifests more frequently as tumors in the head and neck region, with an increased probability of relapse in lymph nodes [1] and has some distinctive morphologic features. The existence of a component of small B-cells within the other CLBCL could lend support to the theory that some of these tumors, more than arise de novo, may have originated in preexistent small B-cell lymphomas, but no firm evidence of this is provided in this study.     

Clinicopathologic reassessment of primary cutaneous B-cell lymphomas with immunophenotypic and molecular genetic characterization

Primary cutaneous B-cell lymphomas (PCBLs) may have particular clinicopathologic characteristics distinct from their lymph node-based counterparts. It has been suggested that PCBLs should have a separate classification system. The aim of this study was to determine whether the Revised European-American Lymphoid Neoplasms (REAL) classification is applicable to PCBL. Thirty-nine cases of PCBL from 36 patients, consisting of 20 men and 16 women (median age 66 yrs), were included in this study. Paraffin-section immunohistochemistry for CD3, CD5, CD10, CD20, CD43, Bcl-2, Bcl-6, and cyclin D1 was performed in all cases. Immunostaining for immunoglobulin light chains was also performed on cases histologically diagnosed as extranodal marginal zone lymphoma (MZL) and primary cutaneous B-cell lymphoma unclassifiable (PCBLu). Polymerase chain reaction (PCR) analysis of t(14;18) was performed in all cases. Immunoglobulin heavy chain gene rearrangement (VDJ) was tested by PCR on all follicle center lymphoma (FCL), MZL, and PCBLu cases. The 39 cases consisted of 15 (39%) FCLs, 13 (33%) diffuse large B-cell lymphomas (DLCL), 9 (23%) extranodal MZL, and 2 cases of PCBLu. Anatomically, 59% of PCBLs occurred in the head and neck, of which approximately 57% were FCL. Five of six cases presenting on the lower extremity were DLCL. Follow-up data was available from all 39 patients with a mean of 50.8 months. All but two patients are alive with or without disease at last contact. One patient with DLCL died of lung metastases and the other DLCL patient died of sepsis as a complication of therapy. In all 15 cases of FCL, CD10 and/or Bcl-6 expression supported the follicle center origin of the neoplastic cells. In contrast to previous reports, we found that 53% (8 of 15) of primary cutaneous FCL had either Bcl-2 protein expression or t(14;18). Our data indicate that many cases of primary cutaneous FCL have Bcl-2 alterations similar to their nodal counterpart. We found that 95% (37 of 39) of PCBLs could be classified according to the REAL classification, supporting its applicability in cutaneous lymphomas.     

Laparoscopy-assisted distal gastrectomy for gastric malignant lymphoma

Although the best treatment for gastric malignant lymphoma remains a controversial matter, surgery is the first choice for localized malignant lymphoma without lymph node metastasis and invasion to the adjacent organ. We report a case of gastric malignant lymphoma that was managed with laparoscopy-assisted distal gastrectomy. A 47-year-old man was referred to our department for management of gastric lymphoma. After preoperative examination revealed a tumor confined to the gastric wall but no lymph node metastasis, we performed laparoscopy-assisted Billroth I gastrectomy. Histopathologic examination confirmed that the tumor was follicular center lymphoma limited to the submucosa with no lymph node metastasis. The postoperative course was good. This is the first reported case of laparoscopic gastrectomy-treated gastric malignant lymphoma. Because it involves minimal access and invasiveness, this procedure may be an effective method of treatment of localized malignant lymphoma of the stomach.     

Cutaneous manifestation of Kikuchi's histiocytic necrotizing lymphadenitis

A young man who presented with cervical Kikuchi's histiocytic necrotizing lymphadenitis later developed a cutaneous plaque lesion. Histologic study of the cutaneous lesion revealed dermal patchy infiltrates composed of large lymphoreticular cells and scattered cells resembling Hodgkin or Reed-Sternberg cells. This condition was initially mistaken for a large-cell lymphoma. But it was later discovered that the dermal cellular infiltrates were similar to that of the involved lymph node. Many of the large cells in the infiltrates were found to be histiocytes. Immunohistochemical study revealed that the cells resembling Hodgkin or Reed-Sternberg cells were activated fibroblasts. The presence of foamy histiocytes and the absence of neutrophils in the skin lesions were also similar to the involved lymph node. Cutaneous Kikuchi's disease may be mistaken for cutaneous lymphoma. Cutaneous involvement by Kikuchi's disease may also denote a worse clinical course.