Ovarian sex cord tumor with annular tubules: an ultrastructural study.

We report the light- and electron-microscopic features of a case of sex cord tumor with annular tubules (SCTAT) in a 15-year-old girl. There was no Peutz-Jeghers syndrome (PJS). The tumor was unilateral, 6 cm in diameter, and encapsulated. Optically, the tumor was composed of cellular nests with tubules and hyaline bodies. There was no cytologic evidence of malignancy. Ultrastructural study revealed that the tumor cells were epithelial, with numerous tonofilaments connected to well-formed desmosomes, but neither Charcot-Böttcher crystalloids or filaments nor Reinke crystals were found. The hyaline bodies were composed of packed basement membranes and cellular debris secondary to cellular necrosis, and resembled Call-Exner bodies. There was no true lumen formation. SCTAT showed granulosa cell differentiation and, to a lesser extent, Sertoli cell differentiation. The value of dark cells as evidence of stromal cell origin is questionable, since they might represent metabolic hyperactive cells. We suggest that SCTAT not associated with PJS is a form of granulosa cell tumor, and when associated with PJS is a form of hamartoma.