Gonadoblastoma : Differential

Comments:
Differential Diagnosis: Gonadoblastoma should be distinguished from pure dysgerminoma and sex cord stromal tumor with annular tubules. If calcification is found within a dysgerminoma, it raises the possibility that it arose in a gonadoblastoma, especially if the patient has dysgenetic gonads and Y chromosome. Sex cord stromal tumor with annular tubules lacks the germ cell component and is composed entirely of sex cord cells.

The immunophenotype of germ cells in gonadoblastoma is similar to dysgerminoma. There is membrane and cytoplasmic positivity for PLAP, CD117 (c-kit), and D2-40 (podoplanin), and nuclear reactivity for OCT4 and SALL4. Sex cord cells show cytoplasmic staining with inhibin, vimentin, and cytokeratin, and nuclear staining with WT1 and FOXL2 (a transcription factor involved in granulosa cell development). They are negative or weakly positive for SOX9 (a transcription factor involved in Sertoli cell development). The hyaline material is PAS positive and stains for laminin. The stromal lutein cells are strongly positive for inhibin and calretinin.

The image shows clusters with admixture of germ cells and sex-cord type cells separated by abundant fibrous stroma and calcified areas.