Carcinosarcoma of the prostate. Report of 21 cases

Carcinosarcoma of the prostate is an unusual malignancy characterized by adenocarcinoma intimately admixed with sarcoma.

The authors reviewed the clinical and pathologic findings of 21 cases of carcinosarcoma of the prostate from the files of the Mayo Clinic.

Patient age ranged from 50 to 89 years (mean, 68 years). Ten patients (48%) had a previous diagnosis of prostatic acinar adenocarcinoma 2-73 months (mean, 33 months) before the diagnosis of carcinosarcoma, 8 of whom had received androgen deprivation therapy and/or radiation therapy in the interim. The Gleason score of adenocarcinoma ranged from 7 to 10 (mean, 9; median, 9). The sarcomas consisted of osteosarcoma (13), leiomyosarcoma (5), fibrosarcoma (1), malignant fibrous histiocytoma (1), and rhabdomyosarcoma (1), and the grade of the sarcoma component ranged from 2 to 4 (mean, 4; median, 4). Adenocarcinoma was the dominant histologic pattern in 7 cases and sarcoma in 14. Immunohistochemical staining revealed cytoplasmic reactivity for prostate specific antigen or keratin in 16 of 16 cases in the adenocarcinoma component. The sarcoma component was positive for vimentin in 16 of 16 cases, actin in 8 of 16 (focal in 2), S-100 protein in 2 of 16, and desmin in 1 of 16. At the time of diagnosis of carcinosarcoma, 11 patients had metastases, including 4 with metastatic adenocarcinoma before the diagnosis of carcinosarcoma. Treatment varied, and nonsurgical therapy was ineffective. Sites of metastases included lung (10 cases), bone (7), brain (4), liver (1), and peritoneum (1). Follow-up ranged from 1 to 107 months after the diagnosis of carcinosarcoma (mean, 34 months; median, 10 months). Mean time to tumor progression was 23 months (range, 1-96 months; median, 18 months). Eighteen patients died of carcinosarcoma from 2 to 107 months (mean, 34 months; median, 9.5 months) after diagnosis. Five-year survival was 41%, and 7-year survival was 14%. Progression and survival were not affected by histologic pattern.

Carcinosarcoma of the prostate is an aggressive malignancy, regardless of histologic type.