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.     

Characteristics of cutaneous lymphomas in Korea

The clinicopathologic characteristics of malignant lymphomas vary according to geography. The aim of this study was to determine the relative frequency of cutaneous lymphomas and to examine the clinical relevance of the WHO classification in Korean cases of cutaneous lymphoma. The Korean Dermatopathology Research Group conducted a clinicopathologic review of a nationwide collection of 80 cutaneous lymphomas, diagnosed at 23 institutes over a recent 3-year period. The clinical records, haematoxylin & eosin-stained slides and immunohistochemical stains from 80 patients with malignant lymphomas of the skin were reviewed. In our study, the most frequent cutaneous lymphoma was mycosis fungoides. Compared with Western countries, Korea had higher rates of NK/T cell lymphoma and subcutaneous panniculitis-like T-cell lymphoma and a much lower rate of B-cell lymphoma. The occurrence rates for various subtypes of malignant lymphoma in Korea are distinct from those in Western countries. The EORTC classification is not fully appropriate in dealing with Korean cases of cutaneous lymphoma, because NK/T cell lymphoma is not included in the EORTC classification for cutaneous lymphoma.     

The new World Health Organization-European Organization for Research and Treatment of Cancer classification for cutaneous lymphomas: a practical marriage of two giants

Following consensus meetings of the two parent organizations, a new World Health Organization-European Organization for Research and Treatment of Cancer (WHO-EORTC) classification for primary cutaneous lymphomas has recently been published. This important development will now end the ongoing debate as to which of these was the preferred classification. The new classification will facilitate more uniformity in diagnosis, management and treatment of cutaneous lymphomas. In particular, it provides a useful distinction between indolent and more aggressive types of primary cutaneous lymphoma and provides practical advice on preferred management and treatment regimens. This will thereby prevent patients receiving high-grade treatment for low-grade biological disease. This review focuses on those diseases which have found new consensus agreement compared with the original WHO and EORTC classifications. In cutaneous T-cell lymphomas, these include folliculotropic mycosis fungoides, defining features of Sézary syndrome, primary cutaneous CD30+ lymphoproliferative disorders (primary cutaneous anaplastic large cell lymphoma, lymphomatoid papulosis and borderline lesions) and subcutaneous panniculitis-like T-cell lymphoma. Primary cutaneous CD4+ small/medium-sized pleomorphic T-cell lymphoma, primary cutaneous aggressive epidermotropic CD8+ T-cell lymphoma and cutaneous gamma/delta T-cell lymphoma are allocated provisional entry status and thereby afford better definitions for some cases of currently unspecified primary cutaneous peripheral T-cell lymphoma. In cutaneous B-cell lymphomas, diseases which have found new consensus agreement include primary cutaneous marginal zone B-cell lymphoma, primary cutaneous follicular centre lymphoma, primary cutaneous diffuse large B-cell lymphoma, leg type and primary cutaneous diffuse large B-cell lymphoma, other. CD4+/CD56+ haematodermic neoplasm (early plasmacytoid dendritic cell leukaemia/lymphoma) now appears as a precursor haematological neoplasm and replaces the previous terminology of blastic NK-cell lymphoma. Other haematopoietic and lymphoid tumours involving the skin, as part of systemic disease, will appear in the forthcoming WHO publication Tumours of the Skin. The new classification raises interesting new problems and questions about primary cutaneous lymphoma and some of these are discussed in this article. It is, however, a splendid signpost indicating the direction in which research in cutaneous lymphoma needs to go. In the interim, we have an international consensus classification which is clinically meaningful.     

Relative frequency of the different types of cutaneous T cell and natural killer cell lymphomas in Korea based on the proposed WHO classification and the EORTC classification

The R.E.A.L. classification was largely adopted recently by the proposed WHO classification. The usefulness of this classification in cutaneous T cell and natural killer (NK) cell lymphomas in Korea was evaluated compared to that of the European Organization for Research and Treatment of Cancer (EORTC) classification. Overall, 78 patients with cutaneous T cell and NK cell lymphomas were diagnosed in Asan Medical Center in the 1990's. The clinical records, slides of H&E and immunohistochemical stainings were reviewed. By the proposed WHO classification, mycosis fungoides (20 cases), lymphomatoid papulosis (13 cases), nasal type NK/T-cell lymphoma (10 cases), CD30+ anaplastic large cell lymphoma (8 cases), subcutaneous panniculitis-like T-cell lymphoma (6 cases), peripheral T-cell lymphoma, unspecified (3 cases), Sézary syndrome (1 case) and blastic NK cell lymphoma (1 case) comprised the primary cases. Secondary or undetermined cases included peripheral T-cell lymphoma, unspecified (10 cases), nasal type NK/T-cell lymphoma (5 cases), and angioimmunoblastic T-cell lymphoma (1 case). EORTC classification for cutaneous T cell and NK cell lymphomas did not include nasal and nasal type NK/T-cell lymphomas, unspecified non-pleomorphic T-cell lymphoma, undetermined cases among primary or secondary ones and some rare types of skin lymphomas which can be classified by WHO. The WHO classification is more useful for skin lymphomas in Korea since it encompassed all the various types of skin T cell and NK cell lymphomas in Korea.     

Characteristics of cutaneous lymphomas in Osaka, Japan (1988-1999) based on the European Organization for Research and Treatment of Cancer classification

Based on accumulating information, European investigators proposed a new classification for primary cutaneous lymphomas known as the European Organization for Research and Treatment of Cancer (EORTC) classification. The clinical utility of this classification in Japanese cases has not been evaluated. Material from 65 patients with cutaneous lymphomas (48 with primary disease and 17 with secondary disease) who were admitted to Osaka University Hospital during the period 1988 through 1999 was reviewed. Immunohistochemical analysis was performed in all cases. Cutaneous T-cell lymphoma (CTCL) comprised mycosis fungoides (15 cases), Sézary syndrome (1 case), lymphomatoid papulosis (5 cases), large cell CTCL (13 cases), pleomorphic small- or medium-sized CTCL (2 cases), and cutaneous natural killer /T-cell lymphoma (4 cases). B-cell lymphomas comprised 7 cases of follicle center cell lymphoma and 1 case of diffuse large B-cell lymphoma of the leg. Each category of disease in the EORTC scheme showed its characteristic features in our series. Five of 13 large cell CTCL cases were positive for CD30, and 5 were negative. The 5-year survival rate of patients with large cell CTCL CD30+ disease was 100% and that of patients with CD30- disease was 0%. (p > 0.1). Only 1 of 7 CTCL cases expressing CD30 was ALK-1+, and all 7 cases showed a favorable clinical course. The EORTC classification is effective in dealing with Japanese cases of cutaneous lymphomas.     

The protean spectrum of non-Hodgkin lymphomas with prominent involvement of subcutaneous fat

BACKGROUND: Subcutaneous T-cell lymphoma (STCL) represents a controversial entity and a confused concept in the field of cutaneous T-cell lymphomas (CTCLs). Recently, alpha/beta+/CD8+ STCL has been recognized by the new World Health Organization (WHO)-European Organization for Research and Treatment of Cancer (EORTC) classification of primary cutaneous lymphomas as a distinct entity in the group of CTCLs. OBSERVATIONS: We reviewed a series of 53 biopsies from 26 patients (F : M = 19:7; median age: 48; range 18-87) of cutaneous B- and T-cell lymphomas characterized by prominent involvement of the subcutaneous tissue. We could classify our cases according to the following seven categories--(i) STCL: n = 16; (ii) extranodal NK/T-cell lymphoma, nasal type: n = 2; (iii) cutaneous gamma/delta T-cell lymphoma: n = 2; (iv) anaplastic CD30+ large T-cell lymphoma: n = 1; (v) diffuse large B-cell lymphoma, secondary cutaneous: n = 3; (vi) lymphoplasmacytic lymphoma, secondary cutaneous: n = 1; (vii) specific cutaneous manifestations of myelogenous leukemia: n = 1. CONCLUSIONS: We demonstrated the protean nature of lymphomas with prominent involvement of the subcutaneous fat tissues. The term STCL should be restricted to a homogeneous group of cases characterized morphologically by an exclusive involvement of subcutaneous tissues, immunohistochemically by a T-cytotoxic alpha/beta phenotype, and biologically by a relatively good prognosis.     

The spectrum of cutaneous lymphomas in patients less than 20 years of age

Cutaneous lymphomas are rare in young patients and are mostly represented by mycosis fungoides and its variants and CD30+ lymphoproliferative disorders (lymphomatoid papulosis [LYP] and anaplastic large T-cell lymphoma). We report our observations in a series of 69 patients less than 20 years of age who presented either with primary cutaneous lymphoma (n = 62) or with secondary manifestations of extracutaneous disease (n = 7). Clinicopathologic features permitted classification of the cases into the following diagnostic categories: mycosis fungoides (n = 24, all primary cutaneous), anaplastic large T-cell lymphoma (n = 13, all primary cutaneous), LYP (n = 11, all primary cutaneous), subcutaneous "panniculitis-like" T-cell lymphoma (n = 1, primary cutaneous), small-medium pleomorphic T-cell lymphoma (n = 2, all primary cutaneous), natural killer (NK)/T-cell lymphoma, nasal-type (n = 1, secondary cutaneous), follicle center cell lymphoma (n = 1, primary cutaneous), marginal zone B-cell lymphoma (n = 7, all primary cutaneous), B-lymphoblastic lymphomas (n = 6, 3 primary and 3 secondary cutaneous), specific cutaneous manifestations of Hodgkin disease (n = 1, secondary cutaneous), and acute myeloid leukemia (n = 2, both secondary cutaneous). Cutaneous lymphoma in children should be differentiated from benign skin disorders that may simulate them. In particular, mycosis fungoides and LYP in this age group may present with clinicopathologic features reminiscent of inflammatory disorders such as pityriasis alba, vitiligo, pityriasis rosea, and pityriasis lichenoides et varioliformis acuta. Even in secondary cutaneous lymphomas, skin manifestations may be the first sign of the systemic disease, and a diagnosis may be achieved on examination of histopathologic specimens of a cutaneous lesion. Our study illustrates the wide spectrum of cutaneous lymphomas and leukemias in patients less than 20 years of age and underlines the need for proper interpretation of these lesions by dermatologists and dermatopathologists.     

World Health Organization classification of hematopoietic and lymphoid tissues: implications for dermatology

The new World Health Organization (WHO) classification of hematopoietic and lymphoid malignancy represents the first worldwide consensus document on the classification of lymphoma/leukemia. Its aim is to supercede all existing classification systems, including the Revised European American Classification (REAL), and the organ-based classification of cutaneous lymphoma proposed in 1997 by the European Organization for Research and Treatment of Cancer (EORTC) cutaneous lymphoma project group. This article compares the REAL, EORTC, and WHO classifications with particular reference to cutaneous lymphoma. It identifies those entities that have been adopted from the EORTC classification, and illustrates important new entities in the category of cytotoxic T-/NK-cell lymphomas that characteristically present in the skin or subcutaneous tissue. However, WHO is not an organ-based classification and some categories (eg follicular B-cell lymphoma and peripheral T-cell lymphoma) include both cutaneous and systemic diseases, and these may have very different prognoses. It is, therefore, important that cancer registries are capable of recording sites of involvement for both B- and T-cell lymphomas so that the incidence and prognosis of cutaneous lymphomas can be established from national data sets in future years.     

Non‐mycosis fungoides cutaneous T‐cell lymphoma: reclassification according to the WHO‐EORTC classification

Background: Non‐mycosis fungoides (non‐MF) primary cutaneous T‐cell lymphomas (PCTCL) are heterogeneous and divided into subgroups by the World Health Organization‐European Organization for Research and Treatment of Cancer (WHO‐EORTC) classification of cutaneous lymphomas. We report the first North American series to examine the applicability of the classification, compare our findings with the predominant European literature and confirm the significance of separation into the indolent and aggressive groups. Methods: Forty‐four non‐MF PCTCL cases with available tissue for phenotyping, adequate clinical staging information and follow‐up were reclassified according to the WHO‐EORTC classification. Results: Non‐MF PCTCL had a longer overall survival (OS) (13.8 years) compared with secondary cutaneous T‐cell lymphoma (SC‐TCL) (2.5 years). Primary cutaneous anaplastic large cell lymphoma (PC‐ALCL) had the most favorable outcome (OS 14.1 years), whereas secondary and primary peripheral T‐cell lymphoma, unspecified had the shortest OS (2.5 and 2.4 years, respectively). Primary cutaneous CD4+ small/medium‐sized pleomorphic T‐cell lymphoma (CTLCD4) appeared to have a favorable course. Conclusions: Most non‐MF PCTCL can be classified according to the WHO‐EORTC classification. The relative frequencies are similar to European experience. Non‐MF PCTCL is a heterogeneous group with a favorable outcome compared to SC‐TCL, especially PC‐ALCL and CTLCD4. Separation of non‐MF PCTCL into indolent and aggressive groups appears clinically significant and may provide direction for therapeutic decisions. Weaver J, Mahindra AK, Pohlman B, Jin T, His ED. Non‐mycosis fungoides cutaneous T‐cell lymphoma: reclassification according to the WHO‐EORTC classification.     

Primary cutaneous T-cell lymphoma occurring after organ transplantation

Lymphoma occurring after organ transplantation has been well described. The majority of cases are B-cell lymphomas and are usually associated with Epstein-Barr virus. Only a minority of posttransplant lymphomas are of T-cell origin, and primary cutaneous T-cell lymphoma (CTCL) is extremely rare. In this article, we report a case of cutaneous peripheral T-cell lymphoma, pleomorphic CD30+ large-cell type, and review the literature relating to posttransplant primary CTCL. Of the 23 cases of posttransplant primary CTCL, 5 patients had erythrodermic disease, and 8 had primary cutaneous anaplastic large cell lymphoma. In addition, there are two cases of mycosis fungoides, one case of subcutaneous panniculitis-like T-cell lymphoma, one case of CD30+ lymphomatoid papulosis, and 6 cases of peripheral T-cell lymphoma, of which 3 were CD30+ large cell lymphomas. Seventeen cases had renal transplants and the majority received both cyclosporine and azathioprine. No consistent viral association was noted among these cases. The sex ratio was 18:5 (male/female), and the mean age at diagnosis was 53 years. Mean time from transplantation to diagnosis is 6.4 years and mean survival time from diagnosis is 14.5 months. The prognoses normally associated with particular subsets of CTCL do not apply in the posttransplant setting.     

Skin is the frequent site for involvement of peripheral T-cell and natural killer cell lymphomas in Korea

We have studied the clinicopathological features of 19 Korean cases of peripheral T-cell and natural killer (NK) cell lymphomas, not including mycosis fungoides. Primary cutaneous involvement was demonstrated in eight of these 19 cases, and we recognized four clinicopathologic subtypes among these eight patients: nasal type NK/T cell lymphoma, three cases; primary cutaneous CD30 positive anaplastic large cell lymphoma, two cases; subcutaneous panniculitis-like T-cell lymphoma, one case; lymphoma with hydroa vacciniforme-like cutaneous lesions, two cases. We did not, however, encounter any cases of HTLV-associated adult T-cell lymphoma/leukemia, which is common in Taiwan and Japan. EBV-associated lymphoma is the most prominent type of peripheral T-cell and NK cell neoplasm involving the skin in Korea.     

Incidence and ten-year follow-up of primary cutaneous lymphomas: a single-centre cohort study

Background

Primary cutaneous lymphomas (PCLs) are a rare group of extranodal non-Hodgkin lymphomas, and epidemiological data in Mediterranean countries are scarce.

Objective

To investigate the incidence and characteristics of PCL in a single tertiary referral centre in Italy.

Materials & methods

A total of 141 PCL patients, seen over a 10-year follow-up period, were investigated.

Results

Incidence rate of PCL was 0.8 cases/100,000 person years. T-cell lymphoma represented 78.7% of all cases, the majority being early mycosis fungoides (MF) (64%; median age: 66 years), followed by lymphomatoid papulosis (LyP) (19%; median: age 48 years), and others (median age: 72 years), including eight cases of anaplastic large CD30+ T-cell lymphoma, four CD4+ smallmedium pleomorphic T-cell lymphoproliferative disorder, four Sézary syndrome, one subcutaneous panniculitis-like T-cell lymphoma, one extranodal NK/T-cell lymphoma nasal-type, and one angioimmunoblastic T-cell lymphoma. B-cell lymphoma accounted for 21.3% of PCL, with 20 cases of cutaneous follicular centre B-cell (median age: 63 years), four primary cutaneous marginal zone, three primary cutaneous diffuse large B-cell, and three leg-type lymphoma. Complete remission within the first year after diagnosis occurred in 70.4% of MF, 61.9% of LyP, 78.9% of other T-cell lymphoma, and 93.1% of B-cell lymphoma cases. Based on a Cox proportional hazard regression model, age, gender, stage, and lactate dehydrogenase and β2-microglobulin blood levels did not predict clinical remission ofMFor LyP.

Conclusions

The incidence and characteristics of PCL in Italy are similar to those in other European countries. PCLs may be diagnosed at very early stages with good prognosis.

     

Clinicopathologic reassessment of non-mycosis fungoides primary cutaneous lymphomas during 17 years

BACKGROUND: New classification systems have recently been proposed for primary cutaneous lymphomas (PCLs). The aim of our study was to evaluate the applicability and significance of the new classification systems to the diagnosis and management of non-mycosis fungoides (non-MF) PCL. METHODS: Immunohistochemical restaining, histological reclassification, and clinical follow-up of all new non-MF PCL cases during 17 consecutive years were performed. The histological reclassification was performed according to the Revised European-American Lymphoma (REAL) classification, except for lymphomatoid papulosis (Lyp), which was included as an indolent lymphoma, according to the European Organization for the Research and Treatment of Cancer (EORTC) classification. RESULTS: During the period 1983-99, 251 new PCL cases were seen, 213 (85%) of which were MF and Sézary syndrome (eight cases), and 38 (15%) of which were non-MF. Of the latter, 20 (53%) were B-cell lymphomas, including eight (40%) follicle center lymphoma, follicular (FCLF), eight (40%) marginal zone lymphoma (MZL), two (10%) diffuse large cell lymphoma, and two (10%) unclassifiable cases. Most or all of the lesions did not stain for CD10, CD43, and bcl-2 protein, and immunostaining for kappa and lambda immunoglobulin light chain restriction was much more useful diagnostically in MZL. Of the 18 primary non-MF cutaneous T-cell lymphomas, 13 (72%) were Lyp, all of which were type A, four (22%) were CD30+ anaplastic large cell lymphoma, and one (6%) was natural killer (NK)/T-cell lymphoma. Except for the NK/T-cell lymphoma, all the other non-MF PCLs had an indolent course. CONCLUSIONS: A minority of the routinely diagnosed PCLs are non-MF, equally divided between B- and T-cell lymphomas. The REAL classification is applicable to the majority, although it does not include entities such as Lyp; the clinical correlations are not as obvious because most of the non-MF PCLs tend to have a relatively indolent course.     

Primary cutaneous diffuse large B-cell lymphoma of the leg according to the new WHO-EORTC classification. Two cases

Primary cutaneous lymphomas are a heterogeneous group of lymphoproliferative disorders characterized by skin involvement with no evidence of systemic disease at the time of diagnosis. Their clinical behavior is generally indolent, and only occasionally is the development of extracutaneous disease observed. Since the 1980s, primary cutaneous B-cell lymphomas have been considered a specific group of lymphomas, differentiated from both T-cell lymphomas and from secondary cutaneous B-cell lymphomas. Both the EORTC and the WHO have proposed alternative classifications for these entities, with significant discrepancies that were finally resolved through the development of a new classification (WHO-EORTC classification for cutaneous lymphomas), which standardizes criteria that had previously been different. We present two new cases of primary cutaneous diffuse large B-cell lymphoma of the leg according to the new classification.     

皮下脂膜炎样T细胞淋巴瘤WHO-EORTC皮肤淋巴瘤分类的新概念

目的:研究皮下脂膜炎样T细胞淋巴瘤(SFTL)的临床病理特征、免疫表型、组织起源和预后.方法:按照2005年皮肤淋巴瘤世界卫生组织-欧洲癌症治疗研究组织(WHO-EORTC)新分类分析6例SPTL患者的临床资料.作常规组织病理检查和免疫组化标记,并对6例患者石蜡组织和1例患者冰冻新鲜组织切片进行15F1标记.结果:6例患者中男2例.女4例,中位年龄25.5岁.临床皮损以无痛性皮下结节和(或)斑块为主,少数患者有发热、贫血和脾大.瘤细胞主要限于皮下脂肪组织内,有异形性和核分裂,并见不同程度脂肪坏死和组织细胞吞噬现象.瘤细胞表达βF1、CD3、CD8、TIA-1、GB、LCA和CD45RO,不表达CD4、CD30、CD56、CD20和CD79a.6例SVTL患者平均随访37个月内均获缓解,仅1例在确诊42个月后因并发糖尿病、高血压及心衰而死亡.结论:SPTL是一种起源于αJβT淋巴细胞的罕见类型细胞毒性皮肤淋巴瘤,临床病程迁延反复,5年生存率高达80%以上.完整充分的免疫组化标记对SPTL的确诊和分型必不可少.     

Nasal type natural killer/T-cell lymphoma with subcutaneous panniculitis-like involvement: Association with a poor prognosis

We report the case of a 23-year-old Japanese man with nasal type natural killer (NK)/T-cell lymphoma and subcutaneous panniculitis-like involvement in the skin. The neoplastic cells possessed the following characteristics of NK cells: expression of cytoplasmic CD3ϵ, CD56, T-cell intracellular antigen-1, azurophilic granules in the cytoplasm, Epstein-Barr virus-encoded small nuclear RNA, and germline configurations of T-cell receptor-β and immunoglobulin heavy chain J genes in the involved tissue. Despite multiple courses of several chemotherapeutic regimens, the cutaneous lesions as well as his general condition deteriorated, and he died of subarachnoidal bleeding. We gathered 14 available reported cases of NK/T-cell lymphoma with subcutaneous panniculitis-like involvement and reviewed the 15 cases, including our patient. They were all of Asian descent. Of the 15 patients (5 men, 10 women), the mean age was 47 years (range, 22-77 years). They had frequent common systemic symptoms: hepatosplenomegaly, weight loss, general weakness, and arthralgia. Twelve of the 15 patients died of disease. The mean duration from diagnosis to death was 9.5 months. NK/T-cell lymphoma with subcutaneous panniculitis-like involvement is associated with a poor prognosis.     

The applicability of the new WHO-EORTC classification of primary cutaneous lymphomas to a single referral center

Recent years have witnessed differences between the World Health Organization (WHO) and the European Organization for Research and Treatment of Cancer (EORTC) classification systems of primary cutaneous lymphomas (PCLs). Recently, a joint WHO-EORTC classification system for PCLs has been reached. This study was performed to assess the applicability of this new classification to a single referral center. All new PCL cases, excluding mycosis fungoides and Sezary syndrome, who were referred from 1999 to 2005 were included. The histological, immunohistochemical stainings and molecular studies were reviewed, and additional stains were performed as needed. The cases were then reclassified according to the WHO-EORTC classifications. The clinical files were also studied, and the patients were followed up clinically. There were 43 new non-mycosis fungoides/Sezary syndrome PCLs, including 29 B-cell lymphomas of which 14 were follicle center lymphoma, 10 marginal zone lymphoma, 4 diffuse large-B-cell lymphoma, leg type, and 1 diffuse large-B-cell lymphoma, other. The 14 T-cell lymphomas included 5 cases of lymphomatoid papulosis, 2 CD30+ anaplastic large-cell lymphomas, 1 NK/T-cell lymphoma, and 6 peripheral T-cell lymphomas, unspecified. Of the 6 "unspecified" T-cell lymphomas, 3 were CD4+ small/medium-sized pleomorphic T-cell lymphoma, which is considered currently a provisional entity under the unspecified T-cell category. The remaining 3 cases could not be classified beyond the unspecified T-cell category, of which 2 cases had an aggressive course. The new WHO-EORTC classification is applicable to most non-mycosis fungoides/Sezary syndrome PCL cases, especially the B-cell lymphomas. However, there is still a substantial subset of T-cell PCLs which cannot be classified beyond the unspecified peripheral T-cell category, some of which may have an aggressive course.     

Non-Hodgkin lymphoma of the skin excluding mycosis fungoides and cutaneous involvement of adult T-cell leukemia/lymphoma*

Forty-nine cases of cutaneous malignant lymphoma were reviewed in order to analyze the clinicopathological features of these neoplasms. Excluding 13 cases of mycosis fungoides and 4 cases of cutaneous involvement of proven adult T-cell lymphoma/leukemia, the remaining 32 cases were further classified according to their pathological and clinical features. There were 12 primary cutaneous lymphomas, 15 cases of secondary cutaneous involvement of systemic lymphoma, and 5 cases of concurrent skin and lymph node involvement. Histologically, large cell lymphoma predominated in both primary and secondary cutaneous lymphomas. Immunohistochemical study using monoclonal antibodies reactive with B- and T-cells in paraffin sections revealed the cellular lineage in 30 cases. Nineteen cases were of T-cell origin and 11 cases were of B-cell derivation. The prognosis of these patients was rather poor; 25 patients died within 5 years. The predominance of T-cell lymphoma contrasts with a higher frequency of cutaneous B-cell lymphoma in Western countries. As the clinicopathological features of cutaneous lymphomas are diverse, it is suggested that cutaneous lymphomas should be classified and studied in a similar way to their nodal counterparts.