Granular cell tumour of the neurohypophysis: an unusual cause of hypopituitarism

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.

Supra-sellar granular cell tumor: Report of a case with literature review

INTRODUCTION AND IMPORTANCE

Granular cell tumor (GCT) originating from the sellar and suprasellar regions, specifically from the neurohypophysis, is a rare neoplasm. Distinguishing GCT from other pituitary tumors, including pituitary adenoma, pituicytoma, and spindle cell oncocytoma, poses significant challenges. Here, we present a rare case of GCT originating from the posterior pituitary in the supra-sellar region.

CASE PRESENTATION

A 41-year-old woman, with no past medical history, presented to neurology department with decreased visual acuity and peripheral facial paralysis since 3 months. The MRI showed a well-defined supra-sellar, retrochiasmatic, oblong, hypothalamic expansive process. It was isointense T1-weighted, discretely hypotensive T2-weighted, measuring 19x17x16 mm, suggesting pituicytoma or craniopharyngioma. An endoscopic transsphenoidal surgical resection was performed. Microscopic examination showed a proliferation of diffuse architecture made up of rounded polyhedral cells with granular eosinophilic cytoplasm. On immunohistochemistry, tumor cells expressed diffusely TTF1, S-100 protein and SOX-10 confirming the diagnosis of supra-sellar GCT.

DISCUSSION AND CONCLUSION

GCTs are rare neoplasms that predominantly exhibit benign behavior, while the malignancy rate remains at 2 %. Histopathology serves as the definitive diagnostic approach for GCTs. These tumors are resistant to radiotherapy and chemotherapy, necessitating surgical resection as the primary treatment modality. Due to the potential absence of distinct tumor masses and local tissue infiltration by tumor cells, complete excision is crucial, with resection extent extending beyond areas of infiltration.

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.

Primary tumors of the posterior pituitary: A systematic review

In 2017, the World Health Organization established that pituicytoma, granular cell tumor (GCT), spindle cell oncocytoma (SCO) and sellar ependymomas (SE) are posterior pituitary tumors (PPT). They probably arise from the pituicytes and may constitute a unique histopathological entity. We carried out a systematic review using PubMed's database. A total of 266 patients with pathological diagnosis of PPT (135 pituicytomas, 69 GCT, 47 SCO, 8 SE and 7 mixed histology tumors) were analyzed. Gender distribution was identical and median age at diagnosis was 48 ± 21.8 years. Main presentation symptoms were visual disorders (n = 142; 58.1%), headache (n = 99; 40.5%), hypopituitarism (n = 84; 34.4%), hypercortisolism (n = 10; 4.1%), polyuriapolydipsia (n = 6; 2.4%) and acromegaly features (n = 5; 2.0%). On MRI, 122 (47.6%) patients showed sellar with suprasellar extension masses, 67 (23.1%) were suprasellar and 63 (24.6%) exclusively sellar. Median tumor size was 22.0 ± 14.2 mm. Two hundred sixty four patients underwent surgery, transphenoidal access was selected in 132 (64.4%) and craniotomy in 58 (28.3%). Complications were hypopituitarism (n = 70; 42.1%), diabetes insipidus (n = 55; 33.1%) and hemorrhage (n = 50; 30.1%). Tumor persisted in 93 patients (45.6%) and recurred in 13 (6.4%). Regarding comparison between main types of PPT, SCO patients were diagnosed later (60.0 vs 47.0 vs 47.0 years, p = 0.023), the tumor was larger 25.0 mm [10.8] vs 20.0 mm [14.2] vs 2.0 mm [15.0] and they were frequently sellar with suprasellar extension tumors (71.7% vs 46.2% vs 32.8%, p = 0.003) compared to pituicytoma and GCT. In conclusion, PPT are rare tumors and have been misdiagnosed mainly as non-functioning pituitary adenomas. Different types of PPT share similar epidemiology, clinical manifestations and surgical outcomes. Surgery is the only curative option but complications and subtotal resection are common.