Granular cell tumor of the sellar region

Granular cell tumor of the sellar region

AKA (infundibular) granular cell tumor (GCT). WHO grade I. Obsolete terms: choristoma1) granular cell myoblastomapituicytoma (this term is now reserved for a circumscribed glial neoplasm). A circumscribed tumor with nests of large cells has granular, eosinophilic cytoplasm due to copious lysosomes in the cytoplasm.

Epidemiology

While rare, GCTs are the most common primary tumor of the neurohypophysis and pituitary stalk/infundibulum 2) with a predilection for the stalk (these result in suprasellar extension). GCTs have been identified in the gastrointestinal tractgenitourinary tract, the orbital region as well as in other locations of the central nervous system with no connection to the pituitary gland or hypothalamus (e.g. spinal meninges 3)). Female: male ratio ≥ 2:1.

Pathology

Asymptomatic microscopic clusters of granular cells (tumorettes) are more common, with an incidence of up to 17% 4).

Clinical

They usually follow a slow progression with benign behavior. The most common presentation is with visual field deficits due to optic chiasm compression 5). However, any symptom typical of a hormonally inactive sellar mass may occur.

Diagnosis

Imaging: may appear radiographically identical to adenomas. Rarely considered in the differential diagnosis pre-op. Isodense on CT and isointense on T1WI MRI, dense homogeneous enhancement on CT & MRI.

Treatment

If GTC is suspected pre-op, a transcranial approach is preferred over transsphenoidal because of the vascularity which has prevented total resection in 60–70% of reported cases 6)XRT may be considered for subtotal resection 7).

Surgical resection is the standard treatment, more recently with transsphenoidal surgery when indicated. Surgical resection results in optimal outcome for patients 8).

Case reports

Three patients had a diagnosis of GCT of the sellar region occurring over an 18-year period. All three patients were followed postoperatively at our multidisciplinary pituitary center (median follow-up = 30 months; range 12-30 months). Hormonal disturbances, an incidental lesion requiring diagnosis, and neurological symptoms were indications for surgery in these patients. Two patients underwent a craniotomy and one underwent endoscopic transsphenoidal surgery. All three patients were free of tumor recurrence at last follow-up. In one case tested, positive thyroid transcription factor-1 (TTF-1) immunohistochemistry was observed.

GCT is generally a benign tumor of the sellar region. Surgical resection is the standard treatment, more recently with transsphenoidal surgery when indicated. Surgical resection results in optimal outcome for patients 9).


A 70-year-old female presented with progressive vision impairment found to have bitemporal visual field defects. Subsequent magnetic resonance imaging (MRI) revealed a 2.9 cm × 2.5 cm × 2.5 cm parasellar mass with extension into the third ventricle and causing optic tract edema (OTE). Right frontotemporal orbital craniotomy was performed and the tumor was partially removed to decompress optic nerves. Pathology identified the tumor as granular tumor of the sellar region. The patient’s vision improved minimally after the surgery. Follow-up MRI after 3 months and 11 months showed stable left OTE.

GCTs were thought to be benign tumors with slow growth, but they could potentially possess aggressive features and invade into surrounding structures as described in this case. OTE can be a rare MRI finding of GCTs. Only one case of GCT-related OTE has been reported in literature to our best knowledge 10).


A 36-year-old neurologically normal woman with known MEN-1 underwent a screening magnetic resonance imaging (MRI) scan which revealed a 10 mm x 6 mm x 7 mm sellar/suprasellar lesion. She underwent endoscopic endonasal transsphenoidal resection. The subsequent neuropathological analysis was consistent with GCT of the pituitary gland. This is the first report of a GCT of the pituitary gland occurring in a patient with MEN-1 11).

References

1) , 5)

Cohen-Gadol AA, Pichelmann MA, Link MJ, et al. Granular cell tumor of the sellar and suprasellar region: clinicopathologic study of 11 cases and literature review. Mayo Clin Proc. 2003; 78:567–573
2) , 7)

Schaller B, Kirsch E, Tolnay M, et al. Symptomatic granular cell tumor of the pituitary gland: case report and review of the literature. Neurosurgery. 1998; 42:166–70; discussion 170-1
3)

Markesbery WR, Duffy PE, Cowen D. Granular cell tumors of the central nervous system. J Neuropathol Exp Neurol. 1973; 32:92–1093
4)

Fuller GN, Wesseling P, Louis DN, et al. Granular cell tumors of the neurohypophysis. In: WHO classification of tumors of the central nervous system. 4th ed. Lyon: International Agency for Research on Cancer; 2007:241–242
6)

Gueguen B, Merland JJ, Riche MC, et al. Vascular Malformations of the Spinal Cord: Intrathecal Perimedullary Arteriovenous Fistulas Fed by Medullary Arteries. Neurology. 1987; 37:969–979
8) , 9)

Ahmed AK, Dawood HY, Cote DJ, Bale TA, De Girolami U, Laws ER Jr, Smith TR. Surgical resection of granular cell tumor of the sellar region: three indications. Pituitary. 2019 Dec;22(6):633-639. doi: 10.1007/s11102-019-00999-z. PubMed PMID: 31620953.
10)

Dai Y, Hagen M, Andaluz N, Bhabhra R. Aggressive granular cell tumor of the neurohypophysis with optic tract edema and invasion into third ventricle. Surg Neurol Int. 2019 Nov 15;10:217. doi: 10.25259/SNI_356_2019. eCollection 2019. PubMed PMID: 31819811; PubMed Central PMCID: PMC6884947.
11)

Pendharkar AV, Lin CY, Born DE, Hoffman AR, Dodd RL. Granular Cell Pituitary Tumor in a Patient with Multiple Endocrine Neoplasia-1. Cureus. 2019 Apr 25;11(4):e4541. doi: 10.7759/cureus.4541. PubMed PMID: 31275768; PubMed Central PMCID: PMC6592835.

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