Retroperitoneal Malignant Mesenchymoma: A Case of Mesenchymal Mixed Tumor with Osteosarcoma, Leiomyosarcoma, Liposarcoma and Fibrosarcoma

Abstract

Malignant mesenchymoma is an interesting but very rare tumor in which malignant differentiation has occurred twice or more. We report a case of retroperitoneal malignant mesenchymoma consisting of osteosarcoma, leiomyosarcoma, liposarcoma and fibrosarcoma. Abdominal CT showed a large retroperitoneal mass with two separate and distinct parts, namely an area of prominent calcification and one of clearly enhancing solid components. The mass contained histologically distinct tumorous components with no histologic admixure at the interfaces. The densely calcified nodule corresponded to osteosarcoma, and the non-calcified clearly enhancing nodules to leiomyosarcoma, liposarcoma and fibrosarcoma.

Primary extraskeletal osteosarcoma of gall bladder

“…4,5 Six histological subtypes, similar to those of the skeletal OS are: 1 chondrosarcoma, malignant mesenchymoma and malignant fibrous histiocytomas are to be considered in GB. 4,6,7 The "reverse zoning phenomenon"of ESOS, i.e. centrally placed osteoid and peripheral spindle cell proliferation, can differentiate from the "zoning phenomenon" of myositis ossificans (periphery with most mature component).…”

Soft tissue tumors and common metastases of the oral cavity

“…Currently, fibrosarcoma accounts for only 1–3% of all sarcomas (56). There are no specific predisposing factors, although some have arisen in the field of previous irradiation and some in pre‐existing soft tissue tumors (23, 34, 88, 113). Fibrosarcoma shows multiple chromosome abnormalities, but only alterations in 2q14–22 have been consistently reported (99).…”