Track

Abstract

A 59-year-old man with a recent history of venous thromboembolism, thalamic stroke, and cauda equina syndrome was admitted with fever, hypoxia, severe back pain, anasarca, and progressive neurologic decline. Autoimmune, infectious, and standard oncologic evaluations were unrevealing. Laboratory evaluation showed thrombocytopenia and elevated lactate dehydrogenase and soluble interleukin-2 receptor. 

Three telescoping punch biopsies from normal-appearing skin with generous subcutaneous fat revealed large, atypical lymphocytes within dermal and subcutaneous vascular lumina, some associated with fibrin thrombi. The atypical cells were diffusely positive for CD20, PAX5, and MUM1; negative for CD3, CD163, and CD30; and showed a high Ki-67 proliferation index (~95–100%). Epstein-Barr virus ISH was negative, and kappa/lambda ISH showed no light chain restriction. 

Intravascular large B-cell lymphoma (IVLBCL) is a rare, aggressive extranodal lymphoma in which clonal B cells selectively proliferate within small-vessel lumina of various organs, including the brain, lungs, liver, spleen, kidneys, and skin, in the absence of lymphadenopathy. Random skin biopsy (RSB) of normal-appearing skin can be a valuable diagnostic tool, particularly when performed as three to four incisional or telescoping punch biopsies from the thigh, abdomen, and/or posterior upper arm, with inclusion of any cherry angiomas if present. Angioma-like lesions may arise from vascular dilatation due to capillary occlusion by neoplastic lymphocytes. Because IVLBCL lesions are more numerous in subcutaneous fat than dermis, deep sampling is critical. This patient’s presentation, including fever, altered consciousness, hypoxemia, thrombocytopenia, elevated LDH, and elevated soluble IL-2 receptor, was highly predictive of a positive RSB.