Unusual button sequestrum in multifocal epithelioid hemangioma of bone: A case report and literature review.

Epithelioid hemangioma is a rare, low-grade vascular tumor defined by epithelioid endothelial differentiation. It has no pathognomonic clinical, laboratory, or imaging features, and its inconsistent nomenclature has historically complicated diagnosis. Although bone involvement is frequent and most lesions behave benignly, some demonstrate local aggressiveness or multifocal spread. We report a unique case of widespread bone lesions exhibiting a "button sequestrum" pattern, previously not described in epithelioid hemangioma. Pathologically, button sequestrum comprises a central island of devitalized bone surrounded by a lucent zone of granulation tissue, a finding that usually narrows the differential diagnosis. Recognizing this presentation broadens the known imaging spectrum of epithelioid hemangioma.