Case: AP171
Contributor's Comment: The official diagnosis of this case is "adult granulosa cell tumor". One participant does not specify the tumor as "adult-type". Four participants classify the tumor as juvenile granulosa cell tumor, and this probably reflects an incomplete understanding of the diagnostic criteria of juvenile granulosa cell tumor, and its distinction from adult granulosa cell tumor. The behavior of adult and juvenile granulosa cell tumor differs markedly. The former is an indolent tumor with a tendency for delayed relapses (probably in the region of 20-30%), while the latter shows relapse in only about 5% of cases and almost always within 3 years.
The two key features that distinguish between adult and juvenile granulosa cell tumor are: (1) Architectural -- Juvenile granulosa cell tumor has a very distinctive low magnification appearance in the great majority of cases -- multiple discrete solid nodules. The nodules are punctuated by multiple irregular or rounded cystic spaces (sometimes producing a microcystic pattern) that often contain secretion of mucin-like material -- the pattern is highly reminiscent of developing follicles.
Adult granulosa cell tumor often grows in the form of sheets and trabeculae, sometimes islands. There are occasional discrete follicle-like nodules, but they are usually focal. Follicular differentiation often takes the form of multiple interspersed small cystic spaces within the solid sheets rather than within discrete nodules.
(2) Cytological -- Adult granulosa cell tumor shows distinctive cytologic features -- pale oval nuclei with frequent grooves; cytoplasm is usually scanty and thus the nuclei often appear crowded or overlapping. Juvenile granulosa cell tumor is characterized by dark round nuclei (with variable degrees of pleomorphism and mitotic activity); cytoplasm is often moderate to abundant due to luteinization.
JKCC