NONPULMONARY SMALL-CELL CARCINOMAS OF EXTRAGENITAL ORIGIN METASTATIC TO THE OVARY

Seven small cell carcinomas of extragenital and extrapulmonary origin that metastasized to the ovary are described. The tumors occurred in women who were 21-77 years of age (mean, 49 years) and were discovered at, or close to, the time of presentation. The primary sites were the intestine (three cases), thymus (two cases), and inguinal skin (one case), and in one case it was undetermined. The ovarian tumors, four of which were bilateral, ranged from 1.2 to 25 cm in diameter (mean, 11 cm). Microscopic examination showed typical features of small (oat) cell carcinoma in six cases; one neoplasm resembled a small cell carcinoma of intermediate cell type and contained rare glands. On immunohistochemical examination, six of six tumors stained for cytokeratin, five of five for neuron-specific enolase, two of six for chromogranin, and none of four for vimentin. The primary cutaneous tumor was a Merkel cell carcinoma. The patient with that case died at 8 months. Two patients with intestinal tumors died at 1 and 2 months, and one is free of disease at 4 years after receiving chemotherapy. Both patients with mediastinal tumors received chemotherapy; one died at 11 months and one had brain metastases at 5 months and was lost to follow-up. The final case is recent. The differential diagnoses in these cases include primary ovarian small cell carcinomas of hypercalcemic and pulmonary types and various other small cell malignant tumors metastatic to the ovary. Consideration of a variety of clinical and pathologic features should enable these important distinctions to be made.