Arch Pathol Lab Med—Vol 125, April 2001 Intrasellar Pituicytoma—Schultz et al 527 Intrasellar Pituicytoma in a Patient With Other Endocrine Neoplasms Alice B. Schultz, MD; Daniel J. Brat, MD, PhD; Nelson M. Oyesiku, MD, PhD; Stephen B. Hunter, MD ● Considered a neoplasm of pituicytes, pituicytoma is a rare and distinct type of glioma that arises in the supra- sellar space and within the sella turcica. Only 12 previ- ously reported cases of pituicytoma are documented in the literature. We report an intrasellar pituicytoma in a 66- year-old man presenting with symptoms and radiologic ap- pearance indistinguishable from a nonfunctional pituitary adenoma. The patient also had a medical history significant for parathyroid adenomas and follicular carcinoma of the thyroid. The intrasellar tumor had morphologic features of a pituicytoma, with interlacing fascicles and a storiform pattern much like a benign fibrous histiocytoma. Immu- noreactivity for S100 was strong, but the tumor lacked in- tercellular collagen type IV. The differential diagnosis of a low-grade spindle cell lesion of the sellar space is dis- cussed, and the literature is reviewed. A summary of the clinical and pathologic features of this case, as well as the 12 previously reported cases, is presented. (Arch Pathol Lab Med. 2001;125:527–530) T he posterior lobe of the pituitary gland or neurohy- pophysis contains unique glial elements referred to as pituicytes. These cells play a supportive role for the axons of large vasopressin and oxytocin-producing neu- rons whose cell bodies reside in the hypothalamus. 1 Among neoplasms that arise from the neurohypophysis, intrasellar granular cell tumors are best known and may originate from pituicytes. 2 In addition, very rare low- grade spindle cell tumors, 3–6 claimed to represent pitui- cytomas and thought to arise from pituicytes, are encoun- tered along the neurohypophysis. The morphologic fea- tures of these tumors are distinct, but their immunophe- notype is somewhat variable. We report a case of pituicytoma and compare its immunophenotypic charac- teristics with those of normal neurohypophysis and other low-grade spindled lesions of the sellar compartment. We describe the first case of pituicytoma that is associated with other endocrine neoplasms. The relevant literature is reviewed and discussed. Accepted for publication September 12, 2000. From the Departments of Pathology (Drs Schultz, Brat, and Hunter) and Neurosurgery (Dr Oyesiku), Emory University School of Medicine, Atlanta, Ga. Reprints: Daniel J. Brat, MD, PhD, Department of Pathology, H190 Emory University Hospital, 1364 Clifton Rd NE, Atlanta, GA 30322 (e- mail: dbrat@emory.edu). REPORT OF A CASE A 66-year-old man presented with lassitude, weakness, poor balance, impaired vision, and headache. This prompted a mag- netic resonance image of the brain, which showed a 1.5  1.5- cm mass in the pituitary fossa with mild effacement of the chi- asm, most consistent with a pituitary adenoma. The pituitary mass was isointense on T1-weighted noncontrast images, en- hanced moderately with gadolinium (Figure 1), and had in- creased signal intensity on proton-density weighted images. A left temporal field deficit was noted on visual field examination. The results of neurological examination were otherwise unre- markable. Medical history was significant for parathyroid ade- nomas removed in 1975. During the neck exploration for his para- thyroidectomies, he was found to have an incidental follicular carcinoma that was treated with total thyroidectomy and post- operative radioactive iodine. He experienced no recurrence of the thyroid carcinoma. Transsphenoidal surgery was performed for diagnosis, resection of the mass, and decompression of the optic chiasm. Visual deficits and other symptoms resolved. No recur- rence of the neoplasm was present 26 months following surgery. PATHOLOGIC FINDINGS The transsphenoidal resection specimen consisted of a soft, yellow, well-circumscribed mass that measured 1.5 cm. Microscopic examination showed a benign, spindle cell neoplasm associated with a rich capillary network. The spindle cells were characterized by oval to elongated, mildly irregular nuclei, and syncytial fibrillary cytoplasm. A single mitotic figure was seen. The spindle cells often radiated around blood vessels (Figure 2). In some areas, spindle cells were arranged in short, curvilinear fascicles that focally formed a storiform-like pattern. Rare swirls were also present. No Verocay bodies, thick-walled blood vessels, Rosenthal fibers, granular bodies, calcifications, or psammoma bodies were present. An immunoperoxidase panel was performed, including glial fibrillary acid pro- tein (GFAP), S100, MIB-1, factor XIIIa, epithelial mem- brane antigen, CD34, chromogranin, neurofilament, syn- aptophysin, type IV collagen, and progesterone receptor. S100 showed strong and diffuse cytoplasmic and nuclear positivity. Collagen type IV showed a perivascular stain- ing pattern but was absent between tumor cells. All other immunostains were negative within the neoplastic cells. The MIB-1 proliferative rate was low, quantitated at 1.5%. COMMENT Pituicytomas are uncommon neoplasms of the neuro- hypophysis. A literature search reveals only 12 examples of this type of neoplasm. 3–6 The pathologic and clinical features of these cases, including our case report, are sum- marized in the Table. Invariably, these tumors are com-