Malignant interstitial cell carcinoma of the testis: report of two cases with steroid synthetic profiles, response to therapy, and review of the literature.

Two cases of malignant interstitial cell carcinoma of the testis are reported. The first patient had no evidence of a virilizing syndrome. Basal plasma testosterone (T) was decreased, whereas plasma luteinizing hormone, estrone (E1), and androstenedione were elevated. These findings were diagnostic of a defect in T secretion as a result of a partial 17-hydroxysteroid dehydrogenase deficiency as seen in male pseudohermaphroditism. In the second patient, showing gynecomastia and atrophic testis, endocrine studies revealed high plasma T and estradiol (E2); all measured delta 4 and delta 5 precursors of T were elevated resembling the pattern seen in virilizing adrenal carcinomas. Both patients were treated with radiotherapy without demonstrable effect. Chemotherapy--consisting of a combination of cis-platinum, vinblastine, and bleomycin; then cyclophosphamide, doxorubicin, and vincristine; and finally o,p'-DDD--was unsuccessful in reducing tumor bulk. Since malignant Leydig cell carcinomas are rare, this paper reviews the literature and makes recommendations concerning treatment.