NEUROLOGY 2008;71:e3
© 2008 American Academy of Neurology
Resident and Fellow Section
Teaching NeuroImage: Spindle cell oncocytoma of the pituitary gland
Muhammad U. Farooq, MD,
Archit Bhatt, MD, MPH and
Howard T. Chang, MD, PhD
From the Department of Neurology and Ophthalmology, Michigan State University, East Lansing.
Address correspondence and reprint requests to Dr. Muhammad U. Farooq, Department of Neurology and Ophthalmology, Michigan State University, East Lansing, MI 48824 muhammad.farooq{at}ht.msu.edu
A 76-year-old man had worsening generalized weakness and headache for several months. MRI showed a solid enhancing sellar mass suggestive of a pituitary macroadenoma (figure 1). Differential diagnoses included pituicytoma, paraganglioma, meningioma, and solitary fibrous tumor. Due to intraoperative bleeding, this tumor was only partially resected. Histopathology revealed interwoven fascicles of eosinophilic spindled cells with features (figure 2, A through D) consistent with pituitary spindle cell oncocytoma, a rare benign tumor with clinical and radiologic presentations indistinguishable from the non-hormone producing macroadenomas.1,2 This patient received radiation therapy postoperatively and showed no change in tumor size during the 2 years after surgery.

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Figure 1 MRI T1-weighted image with gadolinium showing a solid mass within the pituitary fossa (arrow)
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Figure 2 Histopathologic images revealing interwoven fascicles of eosinophilic spindled cells with features
The tumor consists of eosinophilic spindle cells, some with marked nuclear atypia. Focal hemosiderin deposits are seen in the background (A). The tumor cells are immunoreactive for S-100 (B) and EMA (C). The Ki67 labeling fraction is relatively low (D).
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Disclosure: The authors report no disclosures.
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REFERENCES
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- Roncaroli F, Scheithauer BW, Cenacchi G, et al. Spindle cell oncocytoma of the adenohypophysis: a tumor of folliculostellate cells? Am J Surg Pathol 2002;26:1048–1055.[Medline]
- Roncaroli F, Scheithauer BW. Papillary tumor of the pineal region and spindle cell oncocytoma of the pituitary: new tumor entities in the 2007 WHO Classification. Brain Pathol 2007;17:314–318.[Medline]