Spontaneous extraskeletal osteosarcoma in the duodenum of a Crlj:CD1 (ICR) mouse

Abstract

Extraskeletal osteosarcoma is a very rare tumor in humans and animals. This paper describes a case of extraskeletal osteosarcoma observed in the duodenum of a male ICR mouse. Grossly, a solid mass pushing up the tunica serosa was observed in the duodenal wall. Histologically, the tumor was located in the lamina propria mucosae and tela mucosa. Neoplastic cells densely proliferated in these areas, and replaced of the normal tissue components. A small amount of osteoid and a small clump of bone tissue were observed in the area of neoplastic cell proliferation, especially in the lamina propria mucosae. Neoplastic cells consisted of atypical polygonal cells and pleomorphic spindle-shaped cells, and the former were predominant. Mitotic figures were occasionally observed. Neither invasion of vessels in the duodenum nor metastasis to distant organs was observed. There were no skeletal tumors in the body. Immunohistochemically, the neoplastic cells were positive for anti-osteocalcin, osteonectin, vimentin, and S-100 protein. Judging from these results, the present tumor was diagnosed as extraskeletal osteosarcoma. This is the first report of spontaneous extraskeletal osteosarcoma arising from the duodenum of a mouse.

Spontaneous extraskeletal osteosarcoma in the neck skeletal muscle of a Crlj:CD1 (ICR) mouse

“…Osteosarcoma is a malignant tumor that normally develops in the bone tissue; however, there have been few reports on extraskeletal osteosarcoma (EO) in rats and mice 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 . Here, we describe the first reported case of spontaneous EO in the neck skeletal muscle of a mouse.…”

“…Osteocalcin and osterix are reliable markers for osteosarcoma, while myogenin is a marker for rhabdomyosarcoma. Some EO cases have been shown to be positive for vimentin, S-100, and α-SMA 2 , 3 , 4 , 5 , 6 , 7 . PCNA was used to determine proliferation activity.…”