Tumour in a tumour: a well-differentiated spindle cell sarcoma within a forearm lipoma

Abstract

Lipomas are common, benign, soft tissue masses in adults. Sarcomatous change within a giant lipoma is a very rare event. We present a case of a woman presenting with a forearm lipoma that subsequently developed a central, well-differentiated, spindle-cell sarcoma within the lipoma. This case underlines the importance of identifying red flags for referral of soft tissue tumours.

A Low-Grade Myxoid Liposarcoma Arising in a Deep-Seated Conventional Lipoma

“…1 Specifically, lipomas have not been shown to progress to liposarcomas, except for a report of a conventional liposarcoma arising in a subcutaneous lipoma, a study published in an era where molecular diagnostics were not available to confirm the microscopic findings, and a very recent repost of a well-differentiated spindle cell sarcoma arising in an upper extremity lipoma. 7,8 Similarly, mixed-type liposarcomas have occasionally been reported but never with a lipoma component. 9,10 The present case also demonstrates the value of accurate grossing methodology and molecular genetic analysis in the diagnosis of lipomatous soft tissue tumors.…”

“…We are aware of a 2 previous cases of sarcomas arising in a lipoma. 7,8 In this article, we present the case of a young man presenting with a deep-seated tumor of the thigh, which turned out to be a lipoma with a small distinct area of MLS.…”