Endocrine Abstracts

Background: Pituitary abscess is a rare but potentially life-threatening cause of a sellar mass accounting for around 1% of pituitary lesions. Presenting features may be nonspecific with absent systemic infection signs. Cutibacterium acnes is an uncommon cause of pituitary abscess.

Case Presentation: A 16-year-old previously healthy female presented with seven months of severe headaches. She experienced spots of visual loss in the left eye, which progressed at six months to complete visual loss in the left eye. Secondary amenorrhea was noted. MRI revealed a 17 mm sellar lesion with necrotic centre compressing the left optic chiasm. Biochemistry confirmed panhypopituitarism (cortisol 85 nmol/l, fT4 5.0 pmol/l, oestradiol <98 pmol/l, prolactin 269 mIU/l), with normal inflammatory markers (WBC 5.7x10^9/l, CRP 3 mg/l). After initiation of hydrocortisone and levothyroxine, she underwent urgent endoscopic transsphenoidal resection of the sellar lesion. Thick yellow purulent material was encountered, and culture grew Cutibacterium acnes. Histopathology demonstrated granulomatous hypophysitis with mixed lymphohistiocytic infiltration. She received six weeks of intravenous ceftriaxone and oral metronidazole. Postoperatively, she developed transient diabetes insipidus requiring desmopressin. Her headaches improved, vision normalised, and follow-up MRI showed no residual lesion. She remains hypopituitary on treatment.

Discussion: Cutibacterium acnes infections are typically indolent and may provoke only minimal inflammatory response, obscuring diagnosis. Diagnosis of pituitary abscess was based on positive culture and antibiotic response. The histological finding of granulomatous hypophysitis does not directly support a diagnosis of C. acnes abscess. There was no evidence of additional systemic illness such as TB or sarcoidosis. Idiopathic granulomatous hypophysitis remains a possible differential diagnosis.

Conclusion: This case demonstrates an acute presentation of an inflammatory pituitary mass in a teenager treated as Cutibacterium acnes pituitary abscess with good clinical outcome. Idiopathic granulomatous hypophysitis remains a differential, warranting further evaluation if recurrence occurs.