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Case Reports

Abstract

A 39-year-old male former smoker with past medical history of gastroesophageal reflux, myocarditis, hypertension, and hyperlipidemia was referred to the emergency department with right great toe pain and discoloration for five months to rule out vasculitis.  His symptoms began with increased sensitivity and erythema on the toe that continued to worsen with development of new lesions.  An X-ray demonstrated changes consistent with arthritis at the first metatarsophalangeal joint, and an MRI suggested trauma and a fracture.  A CT arteriogram demonstrated a 13 mm pseudoaneurysm of the right anterior tibial artery.  He was subsequently started on aspirin and clopidogrel and surgical management was considered.  Punch biopsy was performed and showed a well-circumscribed proliferation of spindled cells forming irregular and slit-like vascular channels with numerous extravasated red blood cells. The cells were enlarged with prominent nucleoli.  The lesional cells were highlighted by immunohistochemical stains for CD31 and CD34 (focal) and were negative for D2-40 and HHV-8.  Molecular studies revealed the presence of FOS (NM_005252.4:exon:4)::PPP3R1 (NM_000945.4:intron:2) out of frame fusion.  Although FOS rearrangements has been described in a subset of epithelioid hemangiomas, this is more frequently identified within bone and associated with increased cellularity.  Our case describes a novel FOS fusion in a cutaneous epithelioid hemangioma.  The case also emphasizes the role of molecular testing in unusual vascular proliferations.