A Case of Symptomatic Granular Cell Tumor of the Pituitary Treated with Stereotactic Radiosurgery

Treatment modalities and outcomes of granular cell tumors and spindle cell oncocytomas of the pituitary gland: an analysis of two national cancer databases

BACKGROUND

Spindle cell oncocytomas (SCO) and granular cell tumors (GCT) are rare primary pituitary neoplasms; the optimal treatment paradigms for these lesions are unknown and largely unexplored. Thus, using national registries, we analyze the epidemiology, management patterns, and surgical outcomes of SCOs and GCTs.

METHODS

The National Cancer Database (NCDB; years 2003-2017) and the Surveillance, Epidemiology, and End Results Program (SEER; years 2004-2018) were queried for patients with pituitary SCOs or GCTs. Incidence, extent of surgical resection, and rate of postoperative radiation use for subtotally resected lesions comprised the primary outcomes of interest. All-cause mortality was also analyzed via time-to-event Kaplan-Meier curves.

RESULTS

SCOs and GCTs have an annual incidence of 0.017 and 0.023 per 1,000,000, respectively. They comprise 0.1% of the benign pituitary tumors registered in NCDB. A total of 112,241 benign pituitary tumors were identified in NCDB during the study period, of which 83 (0.07%) were SCOs and 59 (0.05%) were GCTs. Median age at diagnosis was 55 years, 44% were females, and median maximal tumor diameter at presentation was 2.1 cm. Gross total resection was achieved in 54% patients. Ten patients (7%) had postoperative radiation. Comparing patients with GCTs versus SCOs, the former were more likely to be younger at diagnosis (48.0 vs. 59.0, respectively; p < 0.01) and female (59% vs. 34%, p = 0.01). GCTs and SCOs did not differ in terms of size at diagnoses (median maximal diameter: 1.9 cm vs. 2.2 cm, respectively; p = 0.59) or gross total resection rates (62% vs. 49%, p = 0.32). After matching SCOs and GCTs with pituitary adenomas on age, sex, and tumor size, the former were less likely to undergo gross total resection (53% vs. 72%; p = 0.03). Patients with SCOs and GCTs had a shorter overall survival when compared to patients with pituitary adenomas (p < 0.01) and a higher rate of thirty-day mortality (3.1% vs 0.0%; p = 0.013).

CONCLUSION

SCOs and GCTs are rare pituitary tumors, and their management entails particular challenges. Gross total resection is often not possible, and adjuvant radiation might be employed following subtotal resection.

Granular cell tumors of the sellar region: what should be done after subtotal resection? A systematic review

PURPOSE

Granular cell tumors (GCT) are highly vascularized and adherent to adjacent structures, and so, complete resection represents a challenge. Adjuvant therapy decisions for residual GCTs currently relies on individual clinician decisions due to a paucity of systematic literature data. We present a comprehensive analysis about the impact of adjuvant therapy in reported cases of patients with incomplete GCT resection.

METHODS

One database (PubMed) and crossed references were queried for GCT with incomplete resection or biopsy from 1962 to 2020. Literature review was performed according to the PRISMA guidelines. Also, two patients with residual GCT from our institutions are added to the analysis. Data regarding clinical presentation, surgical approach, use of adjuvant therapy, Ki-67 labeling, and follow up assessments were extracted and analyzed from selected publications.

RESULTS

Thirty-three studies met the predetermined inclusion criteria and 53 patients were selected (including our two reported cases). The median of age was 49 [IQR, 39-60 years], with a slight male predominance (1.2:1). Among the surgical procedures, seven (13%) were biopsies alone. Adjuvant therapy was used in 18 patients (radiotherapy, 94.5%; chemotherapy, 5.5%) but there is no statistical correlation with adjuvant therapy and the progression of the remnant tumor (p = 0.33). Our institutions' patients did not receive adjuvant therapy and did not show tumor progression on MRI.

CONCLUSION

Our systematic literature review suggests there is a limited role for chemo and/or radiotherapy in the management of incomplete GCT resection. It may be reasonable recommending close clinical follow up in patients with incomplete resection.

Surgical resection of granular cell tumor of the sellar region: three indications

PURPOSE

This case series evaluates the surgical management of granular cell tumor (GCT) of the sellar region. This rare entity presents a unique diagnostic and surgical challenge.

METHODS

Institutional neuropathology databases at Brigham and Women's Hospital and Massachusetts General Hospital were searched for cases with a tissue diagnosis of GCT, and with a location in the sellar region. Patient, treatment, tumor, and follow-up data were extracted.

RESULTS

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.

CONCLUSION

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.