A well-differentiated liposarcoma co-existent with leiomyoma

Area of Science:

• Oncology
• Pathology
• Surgical Pathology

Background:

• Coexistence of well-differentiated liposarcoma (atypical lipomatous tumor) and benign smooth muscle is exceptionally rare in soft tissue neoplasms.
• Retroperitoneal soft tissue tumors present diagnostic challenges due to their location and potential for diverse histologic subtypes.

Observation:

• A case report details a recurrent retroperitoneal tumor in a 50-year-old female.
• Histologic examination revealed a lipomatous component with lipoma-like and sclerosing features of well-differentiated liposarcoma.
• A distinct nodular leiomyoma, representing heterologous smooth muscle differentiation, was observed within the adipocytic tumor.

Findings:

• Immunohistochemical analysis confirmed smooth muscle markers in the leiomyomatous component, with no significant atypia or mitoses.
• The lipomatous component showed features consistent with a well-differentiated liposarcoma, including lipoma-like and sclerosing variants.
• This represents the first reported case of a well-differentiated liposarcoma with a benign smooth muscle leiomyoma in the retroperitoneum.

Implications:

• This finding expands the known spectrum of soft tissue neoplasms, particularly in the retroperitoneum.
• Recognizing leiomyomatous differentiation within liposarcomas is crucial for accurate diagnosis and appropriate management.
• Further research may elucidate the pathogenesis and clinical behavior of such composite tumors.