Ectopic Acromegaly Arising from a Pituitary Adenoma within the Bony Intersphenoid Septum of a Patient with Empty Sella Syndrome

OBJECTIVE: To describe the work-up and treatment of rare ectopic acromegaly caused by a biopsy-proven somatotroph pituitary adenoma located within the bony intersphenoid septum of a patient with empty sella syndrome (ESS). METHODS: We report the presentation, clinical course, diagnostic work-up, and lesion localization and treatment challenges encountered in a 55-year-old patient, with a brief review of relevant literature. RESULTS: A 55-year-old African-American man presented with acromegaly and ESS. Attempts to definitively localize the causative tumor were unsuccessful, though petrosal sinus sampling supported central growth hormone production and imaging suggested bone-enclosed subsellar pituitary tissue. Endoscopic endonasal transphenoidal exploration was undertaken with resection of a somatotroph pituitary microadenoma, and subsequent clinical improvement and biochemical remission. Retrospective review revealed the patient's pituitary to have been located ectopically within a unique bony intersphenoid septum. CONCLUSION: This report describes the first known case of an ectopic pituitary adenoma located within the midline bony intersphenoid septum, which we postulate to have resulted from anomalous embryological pituitary migration. Intra-intersphenoid septal tumors should be considered in cases of apparent central acromegaly with ESS or absence of tumor tissue within the paranasal sinuses or other peripheral locations. INDEXING: Acromegaly, ESS, pituitary adenoma, sphenoid sinus septum.