Spindle cell oncocytoma of pituitary

Case contributed by Dr Ernest Lekgabe

Presentation

Presented with headache and bitemporal hemianopia.

Patient Data

Age: 30
Gender: Female

Well curcumscribed slightly hyperdense pituitary fossa tumour with expansion of the fossa and suprasellar extension.

Mildly T2 hyperintense pituitary fossa tumour with predominantly solid homogenous enhancement, expanding the fossa and with suprasellar extension. Mild flattening of the optic chiasm and optic nerves. No evidence of cavernous sinus invasion.

Post transsphenoidal resection of pituitary fossa tumour. Small volume blood products in the pituitary fossa. No evidence of post operative complication. 

Pathology

MICROSCOPIC DESCRIPTION:

Paraffin sections show fragments of a moderately hypercellular tumour. This is composed of plump spindle cells arranged in loose fasciculi in a fibrous and vascular stroma. A palisaded arrangement of nuclei is noted in some areas. No mitotic figures or areas of necrosis are seen. No normal anterior pituitary tissue is included.

Immunohistochemistry shows strong nuclear staining for TTF-1 in tumour cells and strong cytoplasmic staining for S-100 protein. No staining for GFAP, synaptophysin, SOX10 or epithelial membrane antigen (EMA) is seen in tumour cells. The topoisomerase labeling index is <1%. The features are of spindle cell oncocytoma.

 

DIAGNOSIS:

Spindle cell oncocytoma.

Case Discussion

Spindle cell oncocytoma is a rare primary tumour of pituitary gland, not distinguishable from adenoma on imaging.

Interwoven fascicles of elongated spindled cells are typical on histology.

Lacks staining for cytokeratins, pituitary hormones or neuroendocrine markers.

Usually stains for S100 and thyroid transcription factor 1 (TTF1)

 

Histogenesis of the tumour is not completely understood, not clear if cell of origin is in the anterior or posterior pituitary.

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Case information

rID: 56180
Case created: 16th Oct 2017
Last edited: 19th Oct 2017
Inclusion in quiz mode: Included

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