Introduction: Benign spindle cell neoplasms, notably granular cell tumors, spindle cell oncocytomas, and pituicytomas, comprise a rare subset of intrinsic pituitary lesions with unclear etiology and management.
Methods: Patients diagnosed with a benign spindle cell tumor of the pituitary gland at Partners Healthcare hospitals from 1982-2015 were retrospectively reviewed for patient characteristics, presenting symptoms, radiographic and pathologic features, treatment, and outcomes; as approved by the PHS IRB.
Results: 27 patients with benign spindle cell tumors were identified, including 8 granular cell tumors (GCT), 7 spindle cell oncocytomas (SCOs), and 6 pituicytomas (PCs). The median age at diagnosis was 61.1 years (range: 22.1-80.4) with 48% females. Visual field deficits (56%) and headaches (28%) were the most common presenting symptoms. Abnormally elevated prolactin (44%), low TSH (44%), low LH (43%), and low FSH (38%) were the most common hormonal alterations upon presentation. Pre-operative radiology showed a median lesion size of 1.7 cm (range: 1.4-2.4 cm) with diverse radiographic features. Gross total resection was achieved in 29% of cases, and subtotal resection in 59%. Symptoms and pituitary functions improved post-operatively in 72% of cases.
Conclusions: Benign spindle cell tumors of the pituitary are rare, slow-growing lesions that can present with symptoms of pituitary hormone insufficiency, compression of the optic chiasm, or cavernous sinus cranial nerve palsies. Maximal resection often provides durable symptomatic relief. Our clinical findings contribute to the growing histological and molecular evidence that granular cell tumors, spindle cell oncocytomas, and pituicytomas share a common lineage of differentiation.
Patient Care: Better understanding of the etiology of these rare pituitary lesions will improve their surgical management and outcomes.
Learning Objectives: The audience should better understand the presenting characteristics, radiology, pathology, and management of benign spindle cell tumors of the pituitary.