Endocrine Abstracts

Background: FSH-secreting pituitary adenomas (FSHomas) are rare gonadotroph adenomas accounting for less than 3% of all pituitary adenomas. These tumors typically present with mass effects such as visual disturbances or symptoms of hypopituitarism, with minimal clinical manifestations of hormone excess. Their rarity and subtle presentation often delay diagnosis.

Case Presentation: A 48-year-old male presented with progressive visual impairment and decreased libido over the course of two years. Ophthalmologic evaluation revealed bitemporal hemianopia. Magnetic resonance imaging (MRI) identified a 25 mm pituitary macroadenoma impinging on the optic chiasm. Endocrine workup revealed hypogonadotropic hypogonadism, elevated serum follicle-stimulating hormone (FSH) levels (28 IU/l), and mildly elevated prolactin due to the stalk effect.

Management: Transsphenoidal surgery was performed to relieve optic chiasm compression and achieve tumor debulking. Postoperatively, the patient exhibited partial recovery of visual function. Histopathology confirmed the diagnosis of an FSHoma. Further immunohistochemical analysis of the resected tumor confirmed FSH secretion. Due to incomplete tumor resection, the patient was referred for adjuvant radiotherapy.

Discussion: This case highlights the diagnostic challenge of FSHomas, which often present with non-specific symptoms due to their relatively silent hormonal activity. Surgery remains the cornerstone of treatment, with adjuvant radiotherapy considered in cases of incomplete resection. This report contributes to the limited literature on FSHomas and underscores the importance of considering pituitary adenomas in patients with unexplained hypogonadism and visual field defects.

Conclusion: FSHomas are rare, and early identification is crucial to prevent irreversible visual damage. This case underscores the importance of a multidisciplinary approach in managing complex pituitary adenomas.