Histomorphology and cytomorphology of cutaneous B-cell lymphomas

Primary cutaneous B-cell lymphomas: then and now

In the past, concepts of cutaneous lymphomas were based on careful clinical and classical histopathological descriptions. Most primary cutaneous B-cell lymphomas (pCBCL) were designated as lymphosarcoma, follicular lymphoma, histiocytic lymphoma, reticulum-cell sarcoma or skin reticuloses. Today, pCBCL are classified as a fully recognized and well-defined group of extranodal lymphomas according to the criteria of the World Health Organization-European Organization for Research and Treatment of Cancer classification. Better understanding of the mechanisms of the pathogenesis in pCBCL will hopefully stimulate investigative research and provide further improvement of diagnosis and treatment.

JA. Processos linfoproliferativos da pele: Parte 1 - Linfomas cutâneos de células B

Os linfomas cutâneos primários de células B pertencem ao grupo das neoplasias malignas originadas de linfócitos B, do tipo não-Hodgkin. A rotina diagnóstica nos processos linfoproliferativos de células B é realizada pela biópsia da pele lesada para a análise histopatológica, imuno-histoquímica e pesquisa do rearranjo gênico. A classificação dos linfomas cutâneos primários vem sendo discutida nos últimos anos; as usualmente utilizadas são as propostas pela World Health Organization - WHO e pela European Organization for Research and Treatment of Cancer - EORTC. A recente classificação consensual proposta por WHO-EORTC deverá substituí-las. Entretanto, apesar dos recentes progressos, ainda existem controvérsias e dificuldades quanto à classificação, ao diagnóstico e ao tratamento dos linfomas cutâneos primários de células B.

Primary cutaneous B-cell lymphoma: review and current concepts

PURPOSE

Primary cutaneous B-cell lymphoma (PCBCL) has only recently been recognized as a distinct clinical entity. With the advent of improved immunophenotyping and immunogenotyping, increasing numbers of PCBCL cases are being diagnosed. However, there is much confusion regarding the classification, treatment, and prognosis of these patients. The purpose of this article is to review and analyze the available data to provide the clinician with a concise summary of the diagnosis, prognosis, and treatment of PCBCL.

DESIGN

We conducted a thorough review of the medical literature on PCBCL, with a focus on classification, prognosis, and treatment trials.

RESULTS AND CONCLUSION

PCBCL is defined as a B-cell lymphoma originating in the skin. There is no evidence of extracutaneous disease at presentation and for 6 months after diagnosis, as assessed by adequate staging procedures. Currently, the European Organization for Research and Treatment of Cancer classification is the most concise disease classification scheme, dividing the subtypes of PCBCL by clinical behavior and histopathologic findings. Based on this classification, the most common subtype of PCBCL is follicular center cell lymphoma. PCBCL is generally an indolent form of lymphoma with a good prognosis. Although local cutaneous recurrences are observed in 25% to 68% of patients, dissemination to internal organs is rare. Five-year survival rates typically range from 89% to 96%. A specific subtype, large B-cell lymphoma of the leg, is noted to have a poorer prognosis, with a 5-year survival rate of 58%. Overly aggressive treatment of PCBCL has not been shown to improve survival or prevent relapse. The treatment of choice usually varies depending on the type of PCBCL, the body surface area, and the location of the involvement, as well as the age and general health condition of the patient. The majority of studies indicate that PCBCL is highly responsive to radiation therapy. Polychemotherapy should be reserved for involvement of noncontiguous anatomic sites or those with extracutaneous spread.

Epidermotropic cutaneous B-cell lymphoma mimicking mycosis fungoides

Cutaneous involvement by B-cell lymphoma is often secondary to systemic disease. Primary cutaneous B-cell lymphomas are less common, and patients generally have an excellent prognosis. We present a patient with cutaneous B-cell lymphoma with clinical and histologic features mimicking mycosis fungoides. Although the patient was initially misdiagnosed as having a T-cell lymphoma, immunophenotypic studies demonstrated that this was a B-cell lymphoma.

Evaluation of classic architectural criteria in non-mycosis fungoides cutaneous lymphomas

Ninety-seven cases of non-mycosis fungoides (non-MF) cutaneous lymphoma were evaluated employing published criteria for the categorization of B- and T-cell cutaneous malignancies. Included in the study were 77 primary and secondary cutaneous B-cell lymphomas, in which the diagnosis was supported by immunohistochemical studies identifying lineage. These cases were randomized with 20 cases of non-MF and T-cell lymphoma. Hematoxylin and eosin (H & E)-stained slides from each case were reviewed by at least two dermatopathologists, who were unaware of the previous diagnoses, and a judgment regarding histologic pattern was rendered. The histologic criteria employed emphasized architectural features. For B-cell patterns, these included the presence of dense perivascular, periappendageal and/or nodular collections of lymphocytes, centering in the deep dermis, and separation from the epidermis by a grenz zone. Employed criteria for cutaneous T-cell pattern included location restricted primarily to the upper dermis, interstitial pattern, the presence of epidermotropism, and the lack of a grenz zone. Three B-cell lymphomas were judged to have indeterminate patterns. Four of 74 (5.4%) of the remaining B-cell lymphomas were incorrectly categorized as T-cell lymphomas by architectural criteria. The most striking findings included epidermotropism in rare B-cell lymphomas. Three of the four miscategorized cases were large-cell lymphomas. A preference for B-cell pattern was also confirmed in non-MF T-cell lymphomas. We conclude that most B-cell lymphomas in the skin demonstrate a recognizable B-cell pattern, but rarely a pattern more reminiscent of T-cell lymphoma may be seen. This may occur more often with B-large-cell lymphomas. In addition, this study supports previous work indicating that many non-MF T-cell lymphomas show prominent architectural features typically ascribed to B-cell lymphomas. In summary, our findings support the impression that the vast majority of non-MF lymphomas show a B-cell pattern regardless of their lineage. As such, caution is indicated with regard to pattern interpretation.

Cutaneous B-cell lymphoma--a clinical, pathological and immunohistochemical study

Eleven cases of cutaneous B-cell lymphoma (CBCL) were studied. The ages at presentation ranged from 34 to 79 years (mean = 59.9 years). Six patients were female and five male. Five of the 11 patients had a solitary tumour and the other six had multiple tumours at initial presentation. According to Burg's classification, six cases were at stage I, two stage II, two stage III and one was at stage IV at initial presentation. Abnormalities in laboratory data were rare, except for serum lactic dehydrogenase values. Epidermotropism was not detected, and the area mainly affected by neoplastic cells was the reticular dermis (seven cases) and subcutis (four cases). Biopsy specimens from the patients analysed by immunohistochemical techniques on paraffin or cryostat sections showed CD20 and/or CD22 positivity. Biopsy specimens from two patients which showed CD10 positivity were diffuse large cell types by the working formulation and presented as pre-B-cell lymphoma. At least two groups of CBCL were demonstrable on the basis of prognosis. One was a benign low-grade lymphoma presenting with solitary tumours, mature B-cell markers and intermediate-grade pathology, and the other was a high-grade lymphoma with multiple tumours, pre-B-cell or mature B-cell markers and a poor prognosis.

A case of cutaneous B-cell lymphoma with a storiform stromal reaction

A case of cutaneous B-cell lymphoma is described. The patient was treated only by surgical excision of the skin tumors five times during a period of about two years from February of 1984 to October of 1986. After the last surgical excision, a continuous disease-free period was achieved. Biopsy samples showed dense lymphocytic infiltrations with discrete masses in the dermis and subcutis; one of them showed a storiform pattern. At the time, the infiltrating cells were composed of medium and large lymphoid cells and spindle-shaped cells. The medium and large lymphoid cells were positive for CD20, CD22 and HLA-DR and negative for CD3, CD4, CD5, CD8, CD43, and kappa and lambda light chain. The spindle-shaped cells were negative for CD20, CD43, kappa and lambda light chain, lysozyme, and S-100 protein.

Primary B-cell lymphoma with histologic features of a T-cell neoplasm

A 58-year-old white man had dermatomyositis and primary cutaneous B-cell lymphoma. The cutaneous lymphoma was evidenced by a noduloulcerative disease of the lower extremities. Histologic results resembled a T-cell process with a diffuse, superficial infiltrate composed of small- and medium-sized lymphocytes with angioinvasion and epidermotropism. The infiltrate extended into the deep dermis and panniculus with scattered large lymphocytes and necrosis. With the help of gene-rearrangement analysis and immunophenotyping, the true B-cell lineage was discovered. The importance of gene-rearrangement analysis and immunophenotyping in the diagnosis of cutaneous lymphoma is emphasized.

Clinicopathologic study of cutaneous plasmacytoma

Eight patients with skin tumor lesions composed of dense, predominantly plasma cell infiltrates were studied. Primary cutaneous plasmacytoma can be reactive (polyclonal) or neoplastic (monoclonal). In four of the patients skin lesions were associated with multiple myeloma. Specific skin lesions usually consisted of reddish or purple nodules located on the trunk. In one case the cutaneous lesions developed at the site of previous herpes zoster. Histologically, the cutaneous plasmacytic infiltrate was mainly diffuse and monomorphous. Most of the plasma cells were mature, but in some cases immature immunoblasts and mitoses were observed. Serum immunoelectrophoresis findings correlated with the monoclonality or polyclonality of the plasmacytoma. Presence or absence of systemic involvement cannot be predicted from the appearance of clinical lesions or from maturity of plasma cell infiltration in the skin.

Studies of immunoglobulin and T cell receptor gene rearrangement in cutaneous B and T cell lymphomas

We report two patients with cutaneous B and T cell lymphomas, respectively, in which DNA rearrangement studies were instrumental in establishing a diagnosis. In each case clinical, histopathologic, and immunologic criteria were not sufficient to establish a definitive tissue classification. The use of DNA gene rearrangement studies in the analysis of cutaneous lymphomas is discussed.

Plasmablastic immunoglobulin-secreting lymphoma. Report of a case and a glimpse at the prognosis

The case of a 57-year-old patient with a plasmablastic lymphoma is described. The primary diagnosis was an ordinary plasmacytoma, type IgG kappa. The final course of the disease involved almost all of the organs. The clinical aspect was determined by multiple skin infiltrations. The present report has in common with other published cases the fact that multiple secondary skin involvement of immunoglobulin-secreting tumors, regardless of their origin, have a very poor prognosis. In comparison, primary multiple cutaneous immunoglobulin-secreting tumors have a better prognosis.