Cutaneous Immunocytoma

Abstract

Immunocytomas represent low grade B cell lymphomas related to marginal zone lymphoma but with a predominance of cells having plasmacytic features. Eleven patients presented with lesions compatible with primary cutaneous immunocytoma. The expression of CD2, CD3, CD5, CD20, CD21, CD23, CD43, CD56, CD79, and bcl-2 was analyzed immunohistochemically and of lambda and kappa light chains by an in situ hybridization assay. There were 6 men and 5 women ranging in age from 43 to 76 years. The most common clinical presentation was as extremity based clustered erythematous brown papules. Therapy with local irradiation or Rituximab resulted in lesional resolution. Underlying illnesses included Sjögren's syndrome, hepatitis C, ulcerative colitis, autoimmune thyroid disease, and rheumatoid arthritis. Four patients were taking medications previously associated with immune dysregulation. In two patients in whom a paraproteinemia was uncovered. The most common pattern light microscopically was perivascular small lymphocytic and plasmacellular infiltrates mimicking architecturally a reactive process. Phenotypic studies revealed a marginal zone (MZL) phenotype amid the small atypical lymphocytic infiltrate and highlighted a reactive background population of non-neoplastic T and B cells; light chain restriction was seen amid the plasma cells. In one case there was EBER staining of plasma cells while in another case in whom there was hepatitis C seropositivity staining of plasma cells for hepatitis C associated RNA transcripts was observed. Primary cutaneous immunocytoma appears to arise from a pre-existing state of reactive lymphoid hyperplasia. latrogenic and endogenous immune dysregulation including in the context of lymphotropic viral infections is implicated.

Cutaneous Involvement of Angioimmunoblastic T-Cell Lymphoma Masquerading as B-Cell Reactive Lymphoid Hyperplasia

“…This clinical pattern raised clinically a broad differential diagnosis including several inflammatory diseases (granulomatous rosacea and persistent arthropod bite reactions), infectious diseases (cutaneous leishmaniasis), and lymphoproliferative diseases. In fact, rare cases of primary 15 and secondary 16 cutaneous follicular lymphoma, cutaneous CD30 + lymphoproliferative disorders, 17 primary cutaneous marginal zone B-cell lymphoma, 18 and papular B-cell pseudolymphoma (miliarial-type lymphocytoma cutis) 19,20 have been reported to present with multiple, miliary, and agminated papules.…”