32514 Primary cutaneous marginal zone B-cell lymphoma involution with anetoderma

Abstract

A 57-year-old man presented with an 8-year history of rash on his trunk and limbs. He initially presented with small erythematous patches, which became plaque-like, violaceous, and resolved over months to years with atrophy. The initial clinical impression was of a cutaneous lymphoma or a lupus-like process. A biopsy showed a leucocytoclastic vasculitis with eosinophils with no epidermotropism or basal exocytosis, and loss of elastic fibres in the upper to mid dermis confirming anetoderma in the resolved sites. Immunostaining demonstrated scattered CD3+ T-cells showing a mix of CD4 and CD8 subtypes. CD20 was negative. Few macrophages were CD60+. T-cell gene rearrangement testing was inconclusive. A mildly positive anticardiolipin antibody (10.7, range 0-10) was noted. An inflammatory anetoderma secondary to antiphospholipid syndrome was suspected. Aspirin and warfarin therapy trial showed no benefit. As his rash was stable, he was discharged, but presented 3 years later with a significant flare. On examination he had raised, violaceous and indurated plaques across his trunk. Anetoderma was noted where the rash had resolved. A skin biopsy showed an atypical lymphoid infiltrate consisting of prominent lymphoplasmacytoid cells with lambda-light-chain restriction consistent with a primary cutaneous marginal zone B-cell lymphoma (PCMZL). PCMZL is a form of cutaneous B-cell lymphoma which follows an indolent course. Patients may have solitary skin lesions or present with multiple papulonodular lesions, as in our case. Involution of lesions of PCMZL with secondary anetoderma has been previously described. We present this case of PCMZL involuting with anetoderma to highlight this rare presentation.