SAT-064 - The Great Sellar Masquerader: Pituitary Tuberculosis Presenting As Lymphocytic Hypophysitis

Introduction: Primary pituitary tuberculosis is exceptionally rare, with approximately 110 cases reported in the literature. Sellar tuberculous lesions account for less than 1% of extrapulmonary tuberculosis and represent a small fraction of sellar masses. Patients typically present with headache, visual disturbances, and hypopituitarism, closely mimicking autoimmune hypophysitis. Precise diagnosis is essential, as management strategies differ substantially, and immunosuppression in the setting of unrecognized infection may precipitate life-threatening deterioration.

Case Description: A 24-year-old female presented with secondary amenorrhea, fatigue, and low mood. Hormonal evaluation revealed panhypopituitarism. MRI demonstrated a homogeneously enhancing sellar lesion with stalk thickening, prompting a diagnosis of lymphocytic hypophysitis. Prednisone 30 mg daily and hormone replacement were initiated. On day 33, she developed fever, dyspnea, and hypotension. CT imaging revealed mediastinal and mesenteric lymphadenopathy. Bronchial biopsy demonstrated granulomatous inflammation with Langhans giant cells; acid-fast bacilli staining was negative. History disclosed contact with a family member with extrapulmonary tuberculosis and occupational exposures to tuberculosis patients. Mantoux testing was delayed positive, and QuantiFERON-TB Gold was positive. Disseminated tuberculosis with pituitary involvement was diagnosed. Four-drug antitubercular therapy (isoniazid, rifampicin, ethambutol, pyrazinamide) was initiated alongside steroid and hormone replacement. Following the intensive phase, continuation therapy was maintained. Spontaneous resumption of menses indicated recovery of the hypothalamic-pituitary-gonadal axis, and steroid taper was completed without complication. Follow-up MRI at two years demonstrated complete radiologic resolution.

Conclusion: This case underscores that lymphocytic hypophysitis is a diagnosis of exclusion; infectious etiologies must be excluded before immunosuppressive therapy. Clinical deterioration following corticosteroids warrants urgent reassessment in patients with epidemiologic risk factors. Pituitary tuberculosis may be indistinguishable from autoimmune hypophysitis radiographically, yet therapeutic implications are fundamentally distinct. Timely antitubercular therapy can produce complete resolution and functional recovery, whereas unrecognized infection risks progression under immunosuppression.

Learning Points: Lymphocytic hypophysitis is a diagnosis of exclusion; infectious causes, including tuberculosis, must be excluded before initiating immunosuppressive therapy. Pituitary tuberculosis is potentially reversible, with antitubercular therapy leading to radiologic resolution and possible restoration of hypothalamic-pituitary function.

*Unless otherwise noted, all abstracts presented at ENDO must not be released to the press or the public until the date and time of presentation. For oral presentations, the abstracts are embargoed until the session begins. The Endocrine Society reserves the right to lift the embargo on specific abstracts that are selected for promotion prior to or during ENDO.*