Granulosa theca cell tumor with luteoma in the ovary of a bonnet monkey (Macaca radiata)

A mass was identified on the left caudal region of the abdomen in a 13-year-old bonnet monkey (Macaca radiata). The mass was excised and diagnosed as granulosa theca cell tumor accompanied with luteoma based on the microscopic findings. Morphologically it appeared pink, round, firm multilobulated measured approximately 5 x 3 x 2.5 cm in dimension. Histologically the luteoma composed of polyhedral cells with pale strained vacuolated cytoplasm, centrally located nuclei with distinct cytoplasmic borders. Granulosa theca cell tumor appeared as densely packed spindle shaped fusiform cells arranged in interlacing bundles and whorled pattern with neoplastic cells appearing irregular shaped solid sheets. The concomitant development of granulosa theca cell tumor with luteoma in a single ovary is very rare and is the first reported case in a bonnet macaque to our knowledge.