Congenital juvenile granulosa cell tumour of the testis: report of a case showing extensive degenerative changes.

Juvenile granulosa cell tumour is a rare neoplasm of the testis which occurs predominantly in infancy and which may be associated with sex chromosomal abnormalities. We report an unusual case with deceptive histological features resulting from extensive degenerative changes. In the pedunculated intra-abdominal mass resected from a 1-month-old male baby with 45,X/46,X,iso(Yq) mosaicism, there were multiple large cystic spaces devoid of cellular lining or lined by flat nondescript cells, mimicking various cystic lesions such as multicystic mesothelioma, cystic lymphangioma and cystic dysplasia. The cysts were separated by a highly vascularized fibrous stroma. Only in very rare cysts and the smaller cysts in the region of the pedicle were granulosa cells identified, permitting a diagnosis of juvenile granulosa cell tumour to be made.