Ovarian Fibroma : Differential Diagnosis
Image Description
Differential Diagnosis of Ovarian Fibroma (continued from the previous image):
Adult Granulosa Cell Tumor (AGCT): Diffuse fibromatous areas in AGCT may resemble cellular fibromas; however, AGCT will show grooved nuclei at higher magnification. With reticulin stain, AGCT lacks pericellular fibrillar network unlike fibromas. In AGCT, reticulin fibrils surround nests or clusters of granulosa cells instead of investing each cell. In addition, AGCT will show areas with typical granulosa cell differentiation elsewhere in the tumor. In challenging cases, molecular studies can be performed which will show FOXL2 mutation in 90-95% of AGCT cases.
Luteinized Thecoma: Features supporting the diagnosis of luteinized thecoma with sclerosing peritonitis include - dense cellularity, no cytologic atypia, high mitotic rate, association with sclerosing peritonitis, and hormonal manifestations.
Lastly, other entities that sometimes enter into differential diagnosis of fibromas include: endometrial stromal sarcoma (arteriolar vasculature, no storiform pattern, strong and diffuse CD10 positivity, calretinin -ve) and gastrointestinal stromal tumor (strong CKIT and DOG1 positivity).
This image of an ovarian fibroma shows intersecting fascicles of bland fibroblast-type spindle cells. There is no cytologic atypia and mitotic activity is not increased.
Adult Granulosa Cell Tumor (AGCT): Diffuse fibromatous areas in AGCT may resemble cellular fibromas; however, AGCT will show grooved nuclei at higher magnification. With reticulin stain, AGCT lacks pericellular fibrillar network unlike fibromas. In AGCT, reticulin fibrils surround nests or clusters of granulosa cells instead of investing each cell. In addition, AGCT will show areas with typical granulosa cell differentiation elsewhere in the tumor. In challenging cases, molecular studies can be performed which will show FOXL2 mutation in 90-95% of AGCT cases.
Luteinized Thecoma: Features supporting the diagnosis of luteinized thecoma with sclerosing peritonitis include - dense cellularity, no cytologic atypia, high mitotic rate, association with sclerosing peritonitis, and hormonal manifestations.
Lastly, other entities that sometimes enter into differential diagnosis of fibromas include: endometrial stromal sarcoma (arteriolar vasculature, no storiform pattern, strong and diffuse CD10 positivity, calretinin -ve) and gastrointestinal stromal tumor (strong CKIT and DOG1 positivity).
This image of an ovarian fibroma shows intersecting fascicles of bland fibroblast-type spindle cells. There is no cytologic atypia and mitotic activity is not increased.