Liposarcoma With Extensive Necrosis Obscuring the Diagnosis in an HIV-Positive Patient: A Potential Diagnostic Pitfall

Liposarcoma is one of the most common soft tissue sarcomas in adults; however, its occurrence in patients with HIV is rarely reported. High-grade liposarcomas may demonstrate extensive necrosis, which can complicate pathologic evaluation, particularly in limited biopsy material, and may result in misinterpretation as an infectious or reactive process. We report a 44-year-old HIV-positive man, diagnosed 1 year earlier, with an undetectable viral load, who presented with a deep soft tissue mass initially interpreted on fine-needle aspiration and core needle biopsy (CNB) as an abscess because of extensive acute inflammation and necrosis. Subsequent surgical resection revealed a dedifferentiated liposarcoma (DDLPS) characterized by extensive necrosis and associated acute inflammation, with identification of a well-differentiated component and murine double minute 2 (MDM2) positivity by immunohistochemistry. This case highlights that extensive necrosis and acute inflammation can represent an important diagnostic pitfall in small biopsies, where malignant components may be obscured or absent. It underscores the importance of clinicoradiologic correlation, adequate tissue sampling, and the use of ancillary testing in the evaluation of soft tissue sarcomas.