Korean J Urol.  2006 Oct;47(10):1124-1126. 10.4111/kju.2006.47.10.1124.

Retroperitoneal Extraskeletal Osteosarcoma Misconstrued as a Primary Renal Tumor

• Soh BH
• Han WK
• Lee SH
• Kwon J
• Yang WI
• Yang SC

• KMID: 2139817
• DOI: http://doi.org/10.4111/kju.2006.47.10.1124

Abstract

Extraskeletal osteosarcoma is a rare malignant tumor of the soft tissue. In addition, there are only several reported cases of osteosarcoma of the retroperitoneum as a primary site. We report here on a case of extraskeletal osteosarcoma arising in the retroperitoneum. An 80-year-old man visited our hospital because of a known renal mass. Abdominal computed tomography showed a 10cm sized huge renal mass. We then performed radical nephrectomy. The mass revealed a solid and ivory-colored cut surface with multifocally ovoid cystic spaces and hemorrhage. Microscopically, the tumor consisted of polygonal stromal cells, giant cells and varying amounts of neoplastic new bone; mitotic figures were frequently observed. There was no distant metastasis or regional lymph node involvement.

Keyword

Osteosarcoma

MeSH Terms

Aged, 80 and over
Giant Cells
Hemorrhage
Humans
Lymph Nodes
Neoplasm Metastasis
Nephrectomy
Osteosarcoma*
Stromal Cells

Figure

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  Fig. 1 The computed tomography scan shows the largely calcified right perirenal mass.

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  Fig. 2 The cut surface shows a huge bony mass infiltrating the renal surface.

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  Fig. 3 Histologic appearance of the tumor with spindle-shaped cells and extensive osteoid formation (H&E, ×200).

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  Fig. 4 Histologic appearance of the tumor with anaplastic fibroblast-ike mesenchymal cells that had abnormal mitotic figures (H&E, ×400).

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