Track: Case Reports

Topic: Inflammatory Diseases

Abstract:

Reactive angioendotheliomatosis (RAE) is a benign angioproliferative condition often associated with systemic disorders such as rheumatologic, infectious, cardiac, malignant and renal disease, among others. The histopathology of RAE is characterized by cutaneous vascular endothelial proliferation and hyperplasia without atypia. Clinically, patients present with violaceous purpuric papules and plaques. Intravascular histiocytosis is a rare feature that has been associated with RAE and is thought to represent a reactive histopathological change, also associated with both inflammatory and neoplastic conditions. The literature has suggested that many cases of what was previously thought to be intravascular histiocytosis were later found to be intralymphatic, and that intralymphatic and intravascular histiocytosis likely exist as two distinct entities. We report a case of reactive angioendotheliomatosis with intravascular histiocytosis confirmed with immunohistochemistry, highlighting this rare diagnosis. A 64-year-old male with chronic neutropenia and thrombocytopenia of unknown origin presented with a longstanding purpuric and livedoid rash. A skin biopsy five years prior was consistent with reactive angioendotheliomatosis with intravascular histiocytosis. His rash had since progressed and repeat punch biopsies were obtained. Biopsy demonstrated a proliferation of small superficial and focally deep dermal vessels highlighted by CD31 showing intravascular proliferation of histiocytes, highlighted by CD68. PAX5 and CD20 immunohistochemical stains were negative. CD3 highlighted scattered perivascular T-cells. CD117 showed scattered occasional mast cells. These features were consistent with RAE with intravascular histiocytosis. Extensive systemic workup was conducted, and although no cause was found for his underlying neutropenia and thrombocytopenia, these may be contributing factors.

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Jessica St. John, MD