Cutaneous Lymphomas

Abstract

: Primary cutaneous B-cell lymphomas (PCBCL) are the second most common form of primary cutaneous lymphomas and account for approximately 25%-30% of all primary cutaneous lymphomas. Both forms of low-grade malignant PCBCL, primary cutaneous follicle center lymphoma (PCFCL) and primary cutaneous marginal zone lymphoma of mucosa-associated lymphoid tissue-type (MALT lymphoma) (PCMZL) represent the vast majority of PCBCL and show an indolent slowly progressive course and an excellent prognosis despite a high recurrence rate. Genetic analysis indicates that PCMZL differ from other forms of extranodal MALT lymphomas. The more common class-switched and the non-class-switched form of PCMZL can be distinguished as two distinctive subsets that differ in the cellular composition, IgM expression, and biological behavior with extracutaneous involvement found in the non-class-switched form. Recently, unusual clinical and histological forms of PCMZL and PCFCL manifesting with miliary or agminated lesions have been described that are diagnostically challenging. In contrast to PCMZL and PCFCL, primary cutaneous diffuse large B-cell lymphoma, leg type, and other rare forms of large B-cell lymphomas such as intravascular large B-cell lymphoma have an unfavorable prognosis. There is an emerging group of Epstein-Barr virus (EBV)-driven B-cell lymphoproliferations including posttransplant lymphoproliferative disorders and mucocutaneous ulcer occurring in immunocompromised patients and EBV-associated diffuse large B-cell lymphoma of the elderly arising in the setting of senescence-linked immunodeficiency. This review reports on recent findings expanding the spectrum of clinicopathological features, differential diagnostic aspects, and the pathogenesis of PCBCL and discusses the group of EBV-associated B-cell lymphoproliferations involving the skin.

A literature revision in primary cutaneous B-cell lymphoma

“…In addition, this large cell infiltrate can be admixed with small lymphocytes. Inside the definition of PCDLBL, others are also included cases with different and even rare morphological variants such as anaplastic, plasmablastic, or T-cell/histiocyte-rich B-cell lymphoma,[989] Epstein–Barr virus-positive DLBCL of the elderly, and intravascular lymphoma. [9091]…”

Extranodal Marginal Zone Lymphoma–like Presentations of Angioimmunoblastic T-Cell Lymphoma

“…BCL-2 and, less often, CD43 can be coexpressed in the B-cells. Some cases of MALT lymphoma can show translocation of the MALT1 gene 43 . Subsequent excisional biopsies from the lymphadenopathies in both of our cases revealed the classic features associated with AITL, including effacement of the architecture, proliferation of arborizing FDCs, prominent vascularity, high endothelial venules, and the increased number of immunoblasts.…”

Primary Cutaneous B-Cell Lymphomas in Patients With Impaired Immunity

“…HHV-8, a gamma herpesvirus related to EBV, is capable of infecting B-cells and plasmablasts through virally secreted proteins which can stimulate proliferation of B-cells and plasma cells. In certain cases, HHV-8 induces a B-cell plasmablastic lymphoma, a rare subtype of DLBCL ( 15 , 16 ). Cutaneous lymphomagenesis is related to HHV-8 infection and occurs in a setting of immunodeficiency in this variant, as well as in specific presentations of primary effusion lymphoma in the skin ( 17 , 18 ).…”