Granulosa cell tumors of unilocular cystic type.

We reviewed the clinical, pathological and immunohistochemical features of six unilocular cystic granulosa cell tumors (UCGs) of the ovary. The mean age of the patients was 46 years and the presenting features included abdominal distension, pain, urinary frequency, dyspareunia and amenorrhea. The tumors were unilateral, thin walled and consisted of a single large cavity with a smooth internal lining. The mean tumor-diameter was 10 cm and in all instances the UCGs were of adult histological type. The granulosa cells in six tumors demonstrated immunoreactivity for vimentin, five neoplasms showed reactivity for both alpha-inhibin and progesterone-receptor protein and four showed reactivity for smooth muscle actin. All tumors were nonimmunoreactive with antibodies to epithelial membrane antigen, beta-inhibin, estrogen-receptor protein, testosterone and s100 antigen. Only one of the three patients tested preoperatively had an elevated serum inhibin concentration and this returned to normal six weeks post-operatively. We conclude that UCGs are distinguished by the infrequency of diagnostic serum tumor markers and clinically evident endocrine activity. Correct diagnosis is dependent on histological examination and the finding of a monotonous population of cells, a trabecular growth pattern, nuclear grooves, low mitotic activity and an immunohistochemical profile compatible with granulosa cell tumors.