Abstract
BackgroundExtraskeletal osteosarcoma is a rare malignant mesenchymal tumor, with a predominant occurrence in the extremities. Only two cases of mesenteric extraskeletal osteosarcoma have been documented. We describe an unusual case of extraskeletal osteosarcoma with telangiectatic features occurring in the mesentery.Case presentationA 67-year-old male presented with blood-tinged stool of 1-month's duration. On colonoscopy, a solid mass was detected protruding from the colon wall. Computed tomography showed a 15 × 9.7 cm heterogeneously enhancing mass, with mottled calcification and a cystic portion, occupying the left upper quadrant of the abdominal cavity. Curative resection of the tumor was performed, and the excised tumor was composed of large multilocular cysts containing old hematomas and necrotic debris. The histology revealed an osteosarcoma showing osteoid formation and blood-filled spaces lined with atypical cells. Despite postoperative chemotherapy, he developed a recurrent peritoneal mass and multiple lung metastases 3 months postoperatively.ConclusionGiven the rarity of cases of mesenteric extraskeletal osteosarcoma, its biologic behavior at this location remains to be determined. However, extraskeletal osteosarcoma with telangiectatic features is an uncommon entity to be recognized because of the possible fatal outcome related to the tumors.
Highlights
Extraskeletal osteosarcoma is a rare malignant mesenchymal tumor, with a predominant occurrence in the extremities
Extraskeletal osteosarcoma with telangiectatic features is an uncommon entity to be recognized because of the possible fatal outcome related to the tumors
Extraskeletal osteosarcoma (EOS) is a rare malignant mesenchymal tumor characterized by the production of neoplastic osseous tissues, without attachment to bone or the periosteum [1]
Summary
Extraskeletal osteosarcoma is a rare soft tissue tumor, which is reported to account for approximately 1% of all soft tissue sarcomas and 4% of all osteosarcomas [6,7]. Solid areas in our case showed features of conventional osteosarcoma, the large cystic areas closely resembled telangiectatic EOS. The histological diagnosis in our case was extraskeletal osteosarcoma with telangiectatic features. The criteria for the diagnosis of primary extraskeletal osteosarcoma by Allan et al are as follows: the presence of a uniform morphological pattern of sarcomatous tissue that http://www.biomedcentral.com/1471-2407/7/82 excludes the possibility of malignant mesenchymoma, the production of malignant osteoid or bone by the sarcomatous tissue, and the ready exclusion of an osseous origin [6]. The first detailed report on three cases of telangiectatic EOS noted the absence of osteoid in one case [1] Before those reports on the telangiectatic subtype, the diagnosis of osteosarcoma was strictly defined as a mesenchymal tumor characterized by the direct production of osteoid or bone by malignant cells. Given the rarity of cases of telangiectatic EOS or EOS with telangiectatic features in the literature, we agree with previous publications that more information needs to be obtained concerning the clinical outcome for appropriate management, planning, and prognostic estimation [1]
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