Subcutaneous panniculitis-like T-cell cutaneous lymphoma

Subcutaneous panniculitis-like T cell lymphoma (SPTCL) is a rare cytotoxic T-cell lymphoma classified in the World Health Organization-European Organization for Research and Treatment of Cancer (WHO-EORTC) classification as a unique extranodal lymphoma with characteristic by T cell receptor (TCR) gene rearrangement. We report here a case of SPTCL in a 22 year-old woman who had presented with variably sized multiple nodules on both her legs. Initial differential diagnoses considered were panniculitis and lupus panniculitis. The histopathology showed a predominantly subcutaneous lobular infiltrate with atypical lymphocytes, karyorrhexis and rimming of adipocytes by lymphoid cells. Immunohistochemistry showed CD4-, CD8+, CD56- T-cell phenotype. Although TCR rearrangement studies were not done, the above T-cell phenotype and sparing of epidermis and dermis suggested the possibility of an SPTCL alpha/beta type. The patient received five cycles of a cyclophosphamide, doxorubicin, vincristine and prednisone (CHOP) regimen which resulted in the regression in her skin lesions and constitutional symptoms.     

Systemic panniculitis‐like T‐cell lymphoma with involvement of mesenteric fat and subcutis

Subcutaneous panniculitis‐like T‐cell lymphoma (SPTCL) is an uncommon non‐Hodgkins primary cutaneous lymphoma that typically presents as subcutaneous nodules on the extremities or trunk. Here, we report an unusual case of systemic panniculitic T‐cell lymphoma with predominantly mesenteric extra‐cutaneous involvement and an aggressive clinical course with histopathologic and immunophenotypic features that mimic SPTCL. This case serves to expand the body of literature regarding systemic SPTCL‐like disorders with prominent extra‐cutaneous involvement.     

Rimming of adipocytes by neoplastic lymphocytes: a histopathologic feature not restricted to subcutaneous T-cell lymphoma

Subcutaneous panniculitis-like T-cell lymphoma (SPTCL) is a rare cytotoxic T-cell lymphoma of the skin presenting with histopathologic features simulating those of a lobular panniculitis. The presence of neoplastic T-lymphocytes forming a rim around the individual fat cells in the subcutaneous lobules, so-called "rimming" of adipocytes, is considered a characteristic morphologic feature of this type of cutaneous lymphoma. In this study we reviewed a series of 45 biopsy specimens of primary and secondary cutaneous B- and T-cell lymphomas and one of myeloid leukemia involving the subcutaneous tissues and showing rimming of adipocytes (subcutaneous panniculitis-like T-cell lymphoma: n = 16; mycosis fungoides, tumor stage: n = 3; aggressive epidermotropic CD8(+) T-cell lymphoma: n = 2; cutaneous gamma/delta T-cell lymphoma: n = 4; extranodal NK/T-cell lymphoma, nasal type: n = 4; cutaneous medium-large pleomorphic T-cell lymphoma, NOS: n = 5; CD4(+)/CD56(+) hematodermic neoplasm (blastic NK-cell lymphoma): n = 7; secondary cutaneous large B-cell lymphoma: n = 3; secondary cutaneous lymphoplasmacytic lymphoma: n = 1; specific cutaneous manifestations of acute myelogenous leukemia: n = 1). We could demonstrate that rimming of adipocytes by neoplastic cells can be recognized not only in subcutaneous panniculitis-like T-cell lymphoma, but also in several different entities of malignant lymphoma with skin involvement. Precise classification of cases with prominent involvement of the subcutaneous tissues can only be achieved upon precise correlation of clinicopathologic and phenotypic features. Rimming of adipocytes should not be considered specific of subcutaneous panniculitis-like T-cell lymphoma.     

Lupus profundus, indeterminate lymphocytic lobular panniculitis and subcutaneous T-cell lymphoma: a spectrum of subcuticular T-cell lymphoid dyscrasia

INTRODUCTION: The diagnosis and classification of lymphocytic lobular panniculitis (LLP) has historically proven to be a difficult challenge. We encountered 32 cases of primary LLP which could be categorized as: 1) lupus erythematosus profundus (LEP) (19 patients); 2) an indeterminate group termed indeterminate lymphocytic lobular panniculitis (ILLP) (6 patients); and 3) subcutaneous T-cell lymphoma (SCTCL) (7 patients). OBJECTIVE: We attempted to better define the subtypes of LLP by morphologic, phenotypic and genotypic features and to correlate those features to clinical presentation and outcome. METHOD: Skin biopsy material was studied by conventional light microscopy, through immunophenotyping performed on sections from paraffin-embedded, formalin-fixed tissue and in some cases on sections of tissue frozen after receipt in physiological (Michel's) medium, and by polymerase chain reaction single-stranded conformational polymorphism analysis to assess for clonality of T-lymphocytes. Clinical features were correlated to histologic, phenotypic, and genotypic analyses. RESULTS: Patients with LEP had a prior diagnosis of LE or overlying skin changes which light microscopically were characteristic of LE. Patients with ILLP had no concurrent or prior history of LE, no systemic symptoms or cytopenias, and a clinical course not suggestive of lymphoma. Cases of SCTCL showed hemophagocytic syndrome and/or lesional progression with demise attributable to the disease. Lesions in all groups showed proximal extremity predilection. Females predominated in the LEP group. The average age of onset was 38, 40 and 55 years in the LEP, ILLP and SCTCL groups, respectively. Cytopenia was seen in 4 LEP patients; 1 also developed fever. In LEP and ILLP, lesions resolved with hydroxychloroquine and/or steroid therapy, with recurrences following cessation of therapy. In the SCTCL group 4 developed hemophagocytic syndrome, 4 died within 2 years of diagnosis, and 3 went into remission following chemotherapy. The LEP and SCTCL groups manifested histological similarities: dense perieccrine and lobular lymphocytic infiltration, lymphoid atypia, histiocytes with ingested debris, eosinophilic necrosis of the fat lobule and thrombosis. The atypical lymphocytes although pleomorphic did not have a cerebriform morphology. The infiltrate in ILLP had a similar cytomorphology and distribution with variable angioinvasion which in all save one case was of lesser intensity and was not associated with significant fat necrosis or vasculitis. Germinal centers, dermal/subcuticular mucin deposition and an atrophying interface dermatitis with hyperkeratosis and follicular plugging were largely confined to the LEP group. Erythrophagocytosis, characteristic of SCTCL, usually indicated a supervening subcuticular lymphoid dyscrasia when encountered in ILLP and LEP. SCTCL showed a selective loss of CD5 expression with or without diminution in CD7 and monoclonal CD3 expression. Of 4 cases studied, 3 showed a CD8 dominant infiltrate while 2 others exhibited CD56 and CD30 positivity, respectively. All cases of SCTCL with amplifiable DNA showed T-cell clonality. Similar molecular and phenotypic features indicative of subcuticular lymphoid dyscrasia were encountered in cases of LEP and ILLP including a reduction in CD5, CD7, and/or monoclonal CD3 expression, a preponderance of CD8 lymphocytes within the subcutaneous fat and T-cell clonality. These cases showed lymphoid atypia with variable erythrophagocytosis. Cases of phenotypically abnormal and/or clonal LEP showed one or more of local destruction, lesional size progression, fever, and cytopenias, but lesions responded to hydroxychloroquine and/or prednisone therapy and death attributable to panniculitis could not be documented. Cases that were phenotypically normal and without clonality had none of the aforesaid atypical clinical features. CONCLUSION: Lymphoid atypia, erythrophagocytosis, loss of certain pan T-cell markers, a reduced CD4/8 ratio and TCR rearrangement define subcuticular T-cell lymphoid dyscrasia, including a subset of LEP and ILLP. The subcuticular lymphoid infiltrates represent a spectrum of histologic, immunophenotypic, and molecular abnormalities which range from those which are clearly benign to those which are clearly neoplastic, and also encompasses those cases which defy precise classification into the two aforesaid poles.     

Lethal T- and NK-cell lymphomas mimicking granulomatous panniculitidies: a clinicopathologic study of three cases

An infiltrate mimicking subcutaneous panniculitis associated with a granulomatous response represents an uncommon histopathologic presentation of lymphoma. We report three cases, comprising one case each of nasal-type extranodal NK/T-cell lymphoma, cutaneous γ/δ T-cell lymphoma and human T-lymphotropic virus-I associated adult T-cell leukemia/lymphoma, which based on initial histopathologic and/or clinical presentation were thought to represent systemic lupus erythematosus, sarcoidosis and psoriasiform dermatitis, respectively. Excisional biopsies of indurated lesions performed at our institute; however, in each case showed an atypical subcutaneous lymphohistiocytic infiltrate associated with a variable number of granulomas. Extensive immunophenotypic characterization, in conjunction with histomorphologic and molecular analysis, established the diagnosis of lymphoma in all instances. All patients had a rapidly progressive clinical course and death was attributable to complications of lymphoma shortly after diagnosis. These cases highlight the importance of using a multimodality diagnostic approach to distinguish lymphomas masquerading as granulomatous panniculitis from inflammatory or reactive disorders associated with such histopathologic patterns.     

Subcutaneous panniculitis-like T-cell lymphoma with vacuolar interface dermatitis resembling lupus erythematosus panniculitis

Lupus erythematosus (LE) panniculitis (LEP) is a form of chronic cutaneous LE most often characterized by erythematous subcutaneous nodules. The histopathology of LEP may be distinctive, allowing a diagnosis even in the absence of any other LE features. Lymphocytic infiltration of the panniculus is termed lymphocytic lobular panniculitis. This entity has been reported in both LEP and subcutaneous panniculitis-like T-cell lymphoma. We describe a 67-year-old woman who presented with multiple dermal and subcutaneous nodules on her legs and hips. Biopsy specimens of roughly 15 lesions were interpreted as being diagnostic of LEP, however, with each subsequent biopsy specimen more atypical cells were observed. The patient responded only to moderate doses of oral prednisone, and failed intralesional triamcinolone acetonide, oral immunosuppressive agents, oral antimalarial agents, and oral thalidomide. Three years after the onset of her disease, ulcerated plaques and nodules developed. At this time a T-cell receptor gene rearrangement was present and subcutaneous panniculitis-like T-cell lymphoma was diagnosed. Despite multiple doses of chemotherapy she died approximately 1 year after diagnosis. Patients with apparent LEP that have atypical lymphocytes in their biopsy specimens should be followed up closely for the development of T-cell malignancy.     

A morphologic study of lymphadenosis benigna cutis

Two skin biopsies of lymphadenosis benigna cutis have been analyzed by morphological and immunological methods using monoclonal and polyclonal antibodies on cryostat and paraffin sections. Follicular structures containing active germinal centers are composed of identical cell types as germinal centers of normal lymphatic tissue, e.g. centrocytes, centroblasts, immature plasma cells, dendritic reticulum cells and some T lymphocytes. Outside and inbetween the secondary follicles the infiltrate is composed of small T lymphocytes (OKT-3+, focal positive acid phosphatase reaction). Among T lymphocytes the OKT-4+ to OKT-8+ ratio was 2:1. Within these areas, consisting almost exclusively of T lymphocytes, cells with electron microscopical features of indeterminate cells and interdigitating reticulum cells were recognized. Those cells are OKT-6+. It can be concluded that in lymphadenosis benigna cutis the infiltrate of the dermis is composed of B and T cell areas which show the same microarchitecture and morphology as in normal lymphatic tissue.     

Cutaneous gamma/delta T-cell lymphoma: a histopathologic mimicker of lupus erythematosus profundus (lupus panniculitis)

In the newly revised World Health Organization (WHO)-European Organization for Research and Treatment of Cancer (EORTC) consensus classification for cutaneous lymphomas, cutaneous gamma/delta T-cell lymphoma (CGD-TCL) has been included as a provisional entity. This type of lymphomas, when involving the subcutaneous fat, can mimic both clinically and histologically other more indolent conditions, such as subcutaneous panniculitic T-cell lymphomas (SPTCL) and lupus erythematosus profundus (LEP), and multiple biopsies may be needed to obtain a correct diagnosis. A good correlation of the clinical data with the histopathology and immunohistochemistry are required for diagnosis. Herein, we describe a patient whose initial histopathologic findings ressembled LEP but presented an aggressive clinical course. A new biopsy was performed during the follow-up, and a final diagnosis of CGD-TCL was made.     

Lupus erythematosus panniculitis

Lupus erythematosus panniculitis is an uncommon variant of lupus erythematosus characterized by a specific involvement of the subcutaneous fat. It is a panniculitis with peculiar clinical features and histopathologically characterized by a mostly lobular panniculitis. It may appear in patients with discoid lupus erythematosus and systemic lupus erythematosus, but also as the unique manifestation of lupus erythematosus, and in the latter cases the diagnosis may be problematic. Histopathologic differential diagnosis with subcutaneous panniculitis-like T-cell lymphoma may also be extremely difficult. This article reviews the salient clinicopathologic features and treatment of lupus erythematosus panniculitis, with special emphasis on the histopathologic features.     

Normal subcutaneous fat, necrosis of adipocytes and classification of the panniculitides

The panniculitides represent a group of heterogeneous inflammatory diseases that involve the subcutaneous fat. The specific diagnosis of these diseases requires histopathologic study because different panniculitides usually show the same clinical appearance, which consists of erythematous nodules on the lower extremities. However, the histopathologic study of panniculitis is difficult because of an inadequate clinicopathologic correlation and the changing evolutive nature of the lesions. In addition, large scalpel incisional biopsies are required. From histopathologic point of view, all panniculitides are somewhat mixed because the inflammatory infiltrate involves both the septa and lobules. However, nearly always the differential diagnosis between a mostly septal and a mostly lobular panniculitis is straightforward at scanning magnification on the basis of the structures more intensely involved by the inflammatory infiltrate. Mostly septal panniculitides with vasculitis are actually more vasculitis than panniculitis and include superficial thrombophlebitis and cutaneous polyarteritis nodosa. Mostly septal panniculitides with no vasculitis include erythema nodosum, necrobiosis lipoidica, deep morphea, subcutaneous granuloma annulare, rheumatoid nodule, and necrobiotic xanthogranuloma. Mostly lobular panniculitis with vasculitis is only represented by erythema induratum of Bazin. In contrast, mostly lobular panniculitides without vasculitis comprise a large series of disparate disorders, including sclerosing panniculitis, calciphylaxis, sclerema neonatorum, subcutaneous fat necrosis of the newborn, poststeroid panniculitis, lupus erythematosus profundus, pancreatic panniculitis, alpha(1)-antitrypsin deficiency panniculitis, subcutaneous Sweet syndrome, infective panniculitis, factitial panniculitis, lipodystrophy, traumatic panniculitis, subcutaneous sarcoidosis, and sclerosing postirradiation panniculitis. Finally, some cutaneous lymphomas may simulate panniculitis, both from clinical and histopathologic points of view and, for that reason, they will be included in this review, although they are not inflammatory processes, but authentic lymphocytic neoplasms involving subcutaneous tissue.     

Subcutaneous panniculitic T-cell lymphoma and cytophagic histiocytic panniculitis

A 43-year-old Maori man presented with a 1 month history of malaise, weight loss, anorexia, arthralgia, recurrent fever and tender erythematous subcutaneous skin lesions. Histological examination of an incisional biopsy of a lesion revealed a lobular panniculitis with an inflammatory infiltrate of atypical lymphocytes and evidence of cytophagocytosis consistent with a diagnosis of subcutaneous T-cell lymphoma. The systemic symptoms and skin lesions resolved spontaneously within 3 weeks, only to recur 2 months later, requiring treatment with oral prednisolone. T-cell gene rearrangement studies demonstrated a monoclonal T-cell receptor (gamma-chain) gene rearrangement, further supporting the diagnosis of subcutaneous panniculitic T-cell lymphoma. Treatment with chemotherapy (cyclophosphamide, doxorubicin, vincristine and prednisone) led to remission of symptoms. Four months after completing chemotherapy, the patient remained asymptomatic with a few indurated subcutaneous plaques on the chest. Biopsy of these areas revealed lobular panniculitis, lymphocytic infiltrate without cytological atypia, abundant lipophages and fibrosis and sclerosis consistent with a healing response. He remains well 24 months following chemotherapy.     

Subcutaneous panniculitis-like T-cell lymphoma: a clinicopathological,immunophenotypic and molecular analysis of six patients

BACKGROUND: Subcutaneous panniculitis-like T-cell lymphoma (SPTCL) is a rare cytotoxic T-cell lymphoma of the skin. In the World Health Organization classification of T-cell and natural killer cell lymphoma it is listed as an example of extranodal lymphoma. In practice, however, it is most likely to present to a dermatologist. OBJECTIVES: To describe the clinicopathological, immunophenotypic and molecular features of six U.K. patients with SPTCL. METHODS: The clinical, histological and immunophenotypic features were reviewed. T-cell receptor (TCR) gene analysis was performed on blood and tissue samples using polymerase chain reaction/single-strand conformational polymorphism analysis of the TCR-gamma gene using consensus primers. In situ hybridization was performed on lesional skin to detect mRNA for Epstein-Barr virus (EBV). RESULTS: All patients presented with subcutaneous nodules, plaques or ulceration, and three had systemic symptoms. All biopsies exhibited an infiltrate of medium to large pleomorphic cells involving the subcutis with characteristic rimming of fat spaces. Five showed areas of necrosis, but only one showed marked cytophagia. In three cases the neoplastic cells did not express TCR-beta. One was strongly p53 positive, and the other two were CD56 positive. Both these patients showed epidermal involvement with lichenoid changes histologically, and both developed the haemophagocytic syndrome. The other three cases were TCR-beta positive, CD8 positive and CD56 negative. All cases were positive with pan T-cell markers and also for the cytotoxic granule protein T-cell intracellular antigen-1 and granzyme B. All cases were EBV negative both by immunostaining (latent membrane protein-1) and by in situ hybridization (EBV-encoded mRNA). TCR gene analysis revealed a T-cell clone in four of five cases; two of these patients had an identical T-cell clone in the peripheral blood. The median survival was 16 months. However, two of the three TCR-beta-negative patients have died, whereas none of the TCR-beta-positive patients has died. CONCLUSIONS: This is the first series of SPTCL patients to be reported in the U.K. and the data support the view that there are two subsets of SPTCL: those derived from gammadelta T cells which carry a poor prognosis, and are usually CD56 positive, and a more indolent group derived from alphabeta T cells.     

Diffuse large cell non-Hodgkin's lymphoma, CD30+, T-cell phenotype

A 63-year-old Chinese man presented with an eczematous dermatitis that progressed into a multifocal nodular eruption. Histopathologic examination demonstrated a nodular and diffuse infiltrate in the reticular dermis, which was composed of lymphocytes, macrophages with granulomatous inflammation, and numerous eosinophils. Reactive lymphoid follicles with germinal centers also were present. Immunohistochemistry showed CD30 and LCA. ALK-1 and CD20 were negative. A diagnosis of CD30+ cutaneous T-cell lymphoma was made, and the patient is currently undergoing staging of his disease. Treatment options include excision of nodules, radiation therapy, and systemic chemotherapy.     

Lichen sclerosus with histopathologic features simulating early mycosis fungoides

Mycosis fungoides (MF) is a cutaneous T-cell lymphoma characterized in its early stages by a superficial band-like infiltrate with epidermotropism of lymphocytes without particularly atypical cytologic features. Even though clinicopathologic presentation is diagnostic in typical cases, some inflammatory skin disorders can simulate the histopathologic features of early MF. In this study we present data on 9 patients affected by lichen sclerosus (LS) (M:F ratio 8:1; age range 7-75 years; mean age 31.3 years; median age 13 years), who presented with histopathologic features simulating early lesions of MF. The histopathologic picture was characterized in all cases by a dense, band-like infiltrate of lymphocytes within the superficial dermis, with exocytosis of lymphocytes within the lower part of the epidermis. The papillary dermis was expanded and showed focally coarse bundles of collagen simulating MF. The typical signs of LS were either absent or present only focally. Molecular analyses of the TCRgamma gene rearrangement performed with the polymerase chain reaction (PCR) technique revealed a polyclonal smear in eight cases, and a monoclonal band in one. Our study shows that LS can present with histopathologic features simulating early MF. Especially in cases revealing a monoclonal population of T lymphocytes by PCR, the correct diagnosis may be overlooked without proper clinical information and clinicopathologic correlation. Lichen sclerosus should be added to the list of cutaneous T-cell pseudolymphomas.     

Solitary skin lesions with histopathologic features of early mycosis fungoides

Mycosis fungoides (MF) is a cutaneous T-cell lymphoma that usually begins with cutaneous patches that evolve into plaques and tumors. A few recent reports describe a solitary variant of MF distinct from localized pagetoid reticulosis, a disease in which solitary verrucous lesions occur on acral skin. Solitary skin lesions with some of the histopathologic features of MF rarely occur during treatment with several drugs, especially antidepressants or antihistamines. We analyzed the clinicopathologic features of 20 patients with solitary skin lesions showing histopathologic features of patch- or early plaque-stage MF. Eight men and 12 women (mean age 50.6, range 23-82, median 49) had solitary, small erythematous patches or plaques located on the trunk (16 cases, 6 of them on the breast), upper extremities (3 cases), and inguinal region (1 case). Ten patients were treated with one or more drugs; only two of them received antidepressants or antihistamines. Histopathologic examination revealed in all cases a band-like infiltrate in the upper dermis, frequently with epidermotropism of solitary lymphocytes. Atypical lymphocytes were present in a minority of cases. Immunohistology showed a predominance of CD3+ T lymphocytes, in most cases admixed with clusters of CD20+ B-cells. Only a small proportion of the infiltrate was CD8+. Molecular analysis of the rearrangement of the T-cell receptor genes was performed in 16 cases using the polymerase chain reaction (PCR) technique and revealed a monoclonal band in 8 of them. After surgical excision, 2/14 patients had a recurrence near the surgical scar. In 18 patients with complete follow-up data, no evidence of "classic" MF could be observed after a mean follow-up of 31.9 months. Solitary skin lesions with the histopathologic features of MF can be considered as a distinct clinicopathologic entity, probably representing a solitary variant of mycosis fungoides.     

Cutaneous histopathologic, immunohistochemical, and clinical manifestations in patients with hemophagocytic syndrome. Military Medical Consortium for Applied Retroviral Research (MMCARR).

BACKGROUND AND DESIGN--The hemophagocytic syndrome (HPS) is characterized by fever, wasting, generalized lymphadenopathy, hepatosplenomegaly, and pancytopenia, often with associated coagulopathy. The most common cutaneous manifestations are panniculitis and purpura. Cytophagic histiocytic panniculitis fits within the spectrum of HPS, and the most consistent histopathologic feature in HPS is a proliferation of mature histiocytes that exhibit prominent erythrophagocytosis and cytophagocytosis. The clinical spectrum, the underlying causes, and the histopathologic features found in HPS are broad. The characteristic phagocytic histiocytes seen in HPS have been confused with malignant histiocytes in the past, but are now known to be reactive. The clinical findings, histologic, and immunohistochemical features of 10 cases of HPS with cutaneous lesions were reviewed. Immunohistochemical markers included KP-1, beta F-1, UCHL-1, L-26, MAC-387, factor XIIIa, and S100 protein. RESULTS--The HPS was associated with T-cell lymphoma and/or viral infection. Most biopsy specimens showed edema and hemorrhage with a lymphohistiocytic infiltrate and prominent histiocytic cells showing erythrophagocytosis and, in some cases, cytophagocytosis. The histiocytic cells showed positive reactions for KP-1 and negative reactions for the lymphoid markers. In all cases the lymphoid cells showed a mixed pattern with most cells positive for beta F-1 and UCHL-1, and a small percentage positive for L-26. CONCLUSION--In HPS, the prominent phagocytic histiocytes are reactive and are stimulated by T-cell lymphocytes, either neoplastic or in response to viral infection. Many of the findings in the HPS may also be due directly or indirectly to cytokines produced by proliferating T-cell lymphocytes and/or reactive phagocytic histiocytes.     

Subcutaneous T-cell lymphoma. A clinical and histopathologic study of an additional case

A case of a 62-year-old woman with recurrent subcutaneous nodules, fever and pancytopenia diagnosed as subcutaneous T-cell lymphoma is presented. Incision biopsy revealed lobular panniculitis with an inflammatory infiltrate of atypical T lymphocytes. She was treated with 7 courses of CHOP with transient remission, and she died after 17 months of disease from fatal hemorrhagic complications due to the hemophagocytic syndrome.     

Three unusual histopathological presentations of angiolymphoid hyperplasia with eosinophilia

Angiolymphoid hyperplasia with eosinophilia (ALHE) is a poorly understood benign vasculoproliferative disorder. Histopathologically, the lesions are composed of a dermal or subcutaneous proliferation of blood vessels of varying sizes with plump and bland endothelial cells, which often show vacuolization and protrusion of the cytoplasm into the lumen. The vascular proliferation is admixed with a diffuse inflammatory infiltrate composed of lymphocytes, eosinophils and mast cells. Lymphoid follicles with germinal centers can sometimes be seen. In addition, fibrosis is a common accompanying feature. Some clinical and histopathological variants of ALHE have already been described in the literature. In this report, we present 3 rare associations of ALHE that have not been previously described. Case 1 was a 73‐year‐old woman with a lesion on her right medial thigh. Examination showed ALHE admixed with a chronic lymphocytic leukemic (CLL) infiltrate. Case 2 was a 55‐year‐old woman with a lesion on her right anterior ankle, which was a syringocystadenoma papilliferum co‐existing with an ALHE. Case 3 was a 54‐year‐old man with a lesion on the left medial thigh, which showed overlapping features of IgG4‐related disease associated with areas of ALHE. Given these multiple and diverse associations, it seems likely that ALHE may be a reactive rather than neoplastic process.     

Subcutaneous panniculitic-like T-cell lymphoma and other primary cutaneous lymphomas with prominent subcutaneous tissue involvement

The concept of subcutaneous T-cell lymphoma defines a reduced group of primary cutaneous lymphomas characterized morphologically by a prominent or exclusive subcutaneous tissue involvement. Subcutaneous panniculitic-like T-cell lymphoma is a rare subtype of primary cutaneous T-cell lymphoma clinically mimicking panniculitis. The clinical course is usually protracted with recurrent cutaneous lesions but rarely with early extracutaneous dissemination. The clinical, histopathologic, immunophenotypic, and evolutive features of this heterogeneous and rare group of primary cutaneous lymphomas are reviewed.     

A histopathologic study of arthropod bite reactions in 20 patients highlights relevant adnexal involvement

Background:  Insect bites produce diverse skin reactions. Although quite common, the histopathologic features of arthropod assaults have not ever been studied systemically.
Materials and methods:  Twenty biopsies from cases, clinically diagnosed as arthropod bite reactions between January 2003 and June 2007 were reviewed retrospectively. The aim of the study was to verify as to whether reliable histopathologic criteria could be established based on the frequency of findings observed.
Results:  Epidermal spongiosis (present in 16 of 20 cases), in particular spongiosis of the infundibular epithelium and acrosyringia as well as eosinophilic spongiosis, emerge as relevant diagnostic clues. A moderately dense, superficial and deep infiltrate consisting mainly of lymphocytes and eosinophils was prevalent in the dermis, with eosinophils tending to interstitial and periadnexal distribution. Of note, 19 of 20 (95%) cases revealed periadnexal involvement, whereas 16 of 20 (80%) had the infiltrate extending particularly along the sweat ducts and the coiled glands. In three biopsies, concomitant involvement of sweat glands, hair follicles and sebaceous glands was noted.
Conclusion:  A practical histopathologic algorithm of arthropod bite recognition is proposed. The involvement of the sweat glands in the pattern of arthropod bite reaction is suggested as a new reliable diagnostic clue.