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 noncalcified clearly enhancing nodules to leiomyosarcoma, liposarcoma and fibrosarcoma.
Case Report ; Fibrosarcoma/*radiography ; Human ; Leiomyosarcoma/*radiography ; Liposarcoma/*radiography ; Male ; Mesenchymoma/*radiography ; Middle Age ; Osteosarcoma/*radiography ; Retroperitoneal Neoplasms/*radiography ; Tomography, X-Ray Computed

A fibrosarcoma is a malignant mesenchymal tumor derived from fibrous connective tissue. It usually develops in the deep soft tissues of the extremities, as well as the trunk, head, and neck. In extremely rare cases, a fibrosarcoma may occur in the gastrointestinal tract. Most cases of fibrosarcoma in the gastrointestinal tract have been observed in the pediatric age group while only a few cases have been reported in adults. A 61-year-old male presented with pain in the entire abdominal region. Chest radiography showed free air in the subphrenic space. After an emergency operation, we found a solid mass around the transverse colon and performed a segmental resection with a lymphatic dissection of the transverse colon, including the mass. A pathologic examination showed a fibrosarcoma with a perforation. There was no perioperative complication. The patient was discharged on postoperative day 11 and had follow-ups for 1 year without any recurrence.
Adult* ; Colon, Transverse* ; Connective Tissue ; Emergencies ; Extremities ; Fibrosarcoma* ; Follow-Up Studies ; Gastrointestinal Tract ; Head ; Humans ; Male ; Middle Aged ; Neck ; Peritonitis* ; Radiography ; Recurrence ; Thorax

Congenital infantile fibrosarcoma (CIF) is a rare soft-tissue tumor in the pediatric age group and seldom involves the gastrointestinal tract. A 2-day-old boy was transferred to our hospital with a pneumpoperitoneum. After emergency operation, we could find a solid mass wrapping around a sigmoid colon and performed a segmental resection of sigmoid colon including a mass. Histopathologic examination showed an infantile fibrosarcoma origining from the muscular layer of colon. The baby was discharged on the 17th hospital day and followed for 1 yr without recurrence.
Colon, Sigmoid/pathology ; Fibrosarcoma/congenital/*diagnosis/pathology ; Humans ; Infant, Newborn ; Male ; Peritoneum/radiography ; Positron-Emission Tomography and Computed Tomography ; Soft Tissue Neoplasms/congenital/*diagnosis/pathology

Malignant kidney neoplasms are the most frequently encountered solid kidney masses. Although renal cell carcinoma is the major renal malignancy, other solid malignant renal masses should be considered in the differential diagnosis of solid renal masses that do not contain a macroscopic fatty component. In this pictorial essay, we present the imaging findings of a primitive neuroectodermal tumor, primary liposarcoma of the kidney, primary neuroendocrine tumor, leiomyosarcoma, synovial sarcoma, malignant fibrous histiocytoma, sclerosing fibrosarcoma and renal metastasis of osteosarcoma.
Bone Neoplasms/secondary ; Carcinoma, Renal Cell/pathology/radiography ; Diagnosis, Differential ; Fibrosarcoma/radiography ; Histiocytoma/radiography ; Humans ; Kidney Neoplasms/*pathology/radiography ; Leiomyosarcoma/pathology/radiography ; Magnetic Resonance Imaging ; Middle Aged ; Neuroectodermal Tumors, Primitive/pathology/radiography ; Osteosarcoma/pathology ; Sarcoma ; Sarcoma, Synovial/radiography ; Tomography, X-Ray Computed