Acromegaly

A 48-year-old woman presented with an 18-year history of amenorrhea, headaches, and, during the past 5 years, increasing ring and shoe sizes associated with coarsening facial features. Preoperative laboratory test results revealed a normal prolactin level, a growth hormone level of 1.3 ng/mL (57.2 pmol/L) (reference range,

Transsphenoidal surgery was performed, and gross total resection obtained. Pathologic examination revealed a tumor composed of uniform small cells (Figure, B) and scattered foci of binucleated cells (arrows) that stained for growth hormone (Figure, C and D). The patient's postoperative course was uneventful.

What is your diagnosis?

Pathologie Diagnosis: lntrasellar Gangliocytoma

Gangliocytomas, also known as choristomas, are unusual tumors composed of neural cells with rare intervening glial elements. In the central nervous system, gangliocytomas are most often found in the floor of the third ventricle or hypothalamus and in the temporal and frontal lobes. Unlike hypothalamic gangliocytomas, also known as neuronal hamartomas, pituitary gangliocytomas are not attached to the infundibulum or hypothalamus and tend to be endocrinologically active. Lhermitte-Duclos dis ease (dysplastic gangliocytoma of the cerebellum) is a cerebellar gangliocytoma that often presents in the third to fourth decades of life and is possibly associated with other pathologic conditions, such as heterotopia, hydromyelia, megalencephaly, and Cowden disease. Gangliocytomas are rarely found in the sella, and fewer than 50 cases have been reported in the literature.1-5

Rarely, sellar tumors composed of both adenohypophyseal cells and ganglion cells are encountered, as in this case. Most commonly, gangliocytomas or these mixed gangliocytoma-adenomas are associated with increased growth hormone production; less commonly, the gangliocytomatous neurons can produce growth hormone-releasing hormone or corticotropin-releasing hormone, leading to somatomammotroph or corticotroph adenomas, respectively. Geddes et al1 and Weil et al6 hypothesized that gangliocytomas represent neuronal differentiation of pituitary adenoma cells, which may possess some developmental plasticity, as has been shown in adenomas in patients with multiple endocrine neoplasia type 1. Others suggest that gangliocytomas represent growth of ectopic hypothalamic neurons.2,4,5 Another hypothesis suggests that both neuronal and adenohypophyseal cellular elements in these tumors arise from embryonic rests that contain cells with features intermediate between neurons and adenohypophyseal cells.5 Finally, as noted herein, the term sellar ganglion tumors can be confusing, and tumors that arise within the sella are best described as intrasellar gangliocytomas or, when composed of both elements, mixed gangliocytomaadenoma.5 Outside the sellar region, these ganglion cell neoplasms may be more likely to show neoplastic growth patterns or, on rare occasions, to invade adjacent structures.5

At 2 years postoperatively, the patient's growth hormone level is 1.0 ng/mL (44 pmol/L) and her insulin growth factor 1 level is 265 ng/mL (reference range,

References

1. Geddes JF, Jansen CH, Robinson SFD, elal. Cangliocytomas of the pituitary: a hcterogenous group of lesions with differing histogenesis. Am J Surg Pathot. 2000:24:607-613.

2. Horvath E, Kovacs K, Scheithauer BW, et al. Pituitary adenoma with neuronal choristoma (RANCH): composite lesion or lineage infidelity? Ulfrasfrucf Pathol. 1994:18:565-574.

3. McCowen KC, Glickman JN, Black PM, Zervas NT, Lidov HG, Garber JR. Gangliocytoma masquerading as a prolactinoma. J Neurosurg. 1999;91:490-495.

4. Serebrin R, Robertson DM. Ganglioneuroma arising in the pituitary fossa: a twenty year follow-up. J Neurol Neurosurg Psychiatry. 1984;47:97-98.

5. Towfighi J, Salam MM, McLendon RE, Powers S, Page RB. Ganglion cell-containing tumors of the pituitary gland. Arch Lib Pathol Mcd. 1996; 120:369-377.

6. Weil RJ, Huang S, Pack S, et al. Pluripotent tumor cells in benign pituitary adenomas associated with multiple endocrine neoplasia type 1. Cancer Res. 1998;58:4715-4720.

John K. Song, MD; Robert J. Weil, MD

Accepted for publication September 7, 2004.

From the Department of Neurosurgery, Vanderbilt University School of Medicine, Nashville, Tenn (Drs Song and Weil); and Brain Tumor Institute, Cleveland Clinic Foundation, Cleveland, Ohio (Dr Weil). Dr Song is currently with Department of Neurosurgery, University of Chicago, Chicago, Ill.

The authors have no relevant financial interest in the products or companies described in this article.

Corresponding author: Robert ). Weil, MD, Brain Tumor Institute, Cleveland Clinic Foundation, Taussig Cancer Center/Desk R-20, 9500 Euclid Ave, Cleveland, OH 44195 (e-mail: weilr@ccf.org).

Reprints not available from the authors.

Copyright College of American Pathologists Mar 2005
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