Granulosa cell tumour of the ovary with a pseudopapillary pattern

Both juvenile and adult granulosa cell tumour may have a pseudopapillary pattern.

Macroscopic appearances

The tumour is unilateral and usually cystic, unilocular or multilocular. The cyst wall is lined by multiple papillary projections.

Histopathology

Pseudopapillae (lacking fibrovascular cores) are formed with by cellular projections surrounded by necrosis or by folds of neoplastic cells without necrosis. The pseudopapillae are lined by a layer of cells several deep. All cases show areas of typical granulosa cell tumour.

Immunohistochemistry

	Inhibin	3/31
	Calretinin	2/21
	CD99	1/11
	Cam5.2	1/2(focal positivity)1

Differential diagnosis

Transitional cell / Brenner neoplasm: form true papillae with fibrovascular cores: usually positive for CK7.
Endometrioid adenocarcinoma: positive for EMA and CK7.
Undifferentiated carcinoma with pseudopapillae.
Retiform variant of Sertoli-Leydig cell tumour: the papillae have stromal cores, often with marked hyalinisation.
Melanoma may form pseudopapillae.
Ovarian ependymoma: there are long fibrillary cytoplasmic processes, perivascular pseudo-rosettes and true rosettes; the tumour is positive for glial fibrillary acidic protein.

References

1 Irving Granulosa Cell Tumors of the Ovary With a Pseudopapillary Pattern: A Study of 14 Cases of an Unusual Morphologic Variant Emphasizing Their Distinction From Transitional Cell Neoplasms and Other Papillary Ovarian Tumors. Am J Surg Pathol 2008;32:581586