Objectives: To investigate primary osteosarcoma (osteogenic sarcoma) of the kidney, a rare and aggressive neoplasm.
Methods: We present clinical and pathologic features of three female patients, aged 50, 66, and 78 years, affected by primary osteosarcoma of the kidney. The diagnosis was made by H&E-stained samples from totally (cases 1 and 2) or partially (case 3) embedded tumors.
Results: Reported cases showed histologic features of low-grade (n = 1), chondroblastic (n = 1), and osteoblastic (n = 1) osteosarcoma. Tumor size ranged from 3 to 7 cm, and pT category was pT1a (n = 1), pT1b (n = 1), and pT3a (n = 1). Immunohistochemistry gave focal positive results with PAX2 and CD10 in case 1 and S100 in case 2. On follow-up, two patients were disease free at 25 and 68 months and one died of metastases.
Conclusions: Surgically treated primary renal osteosarcoma might not be as aggressive as previously thought if diagnosed early with low pT status.
Keywords: Kidney; Osteogenic sarcoma; Osteosarcoma; Primary renal sarcoma; Soft tissue tumor.