Endocrine Abstracts

Background: We report a case of a 35-year-old male presenting with pituitary dysfunction secondary to an optochiasmal cavernoma.

The gentleman was initially referred with gynaecomastia and biochemical tests consistent with secondary hypogonadism. On further questioning he also reported extremely lethargy, difficulties with weight loss and poor libido. Examination was consistent with features of hypogonadism with reduced body hair, bilateral gynaecomastia and microorchidism. Visual fields were full on direct confrontation.

Investigations: Insulin stress test noted sub-optimal responses for both GH and cortisol in the presence of adequate hypoglycaemia. GnRH test showed reduced basal levels of testosterone 0.7 nmol/l (range: 9–40 nmol/l), LH 0.7 U/l (range: 2–10 U/l) and FSH 0.6 U/l (range: 2–8 U/l) with normal LH but blunted FSH response post stimulation. TRH test showed normal TSH response with declining free T4 levels. MRI scan of pituitary showed a 1 cm hypointense mass arising from the chiasm and extending into the suprasellar cistern, suggestive of a optochiasmal cavernoma.

Management: Current treatment involves hormone replacement therapy with hydrocortisone, levothyroxine and testosterone. The patient remains under close follow-up with on-going additional radiological investigations.

Discussion: Optochiasmal cavernoma is a rare variant of cavernous hemangioma with limited cases reported in the literature. Presenting symptoms are usually related to visual field defects. Patients are prone to bleeding and stroke with sudden vision loss. MRI remains diagnostic modality of choice with differential diagnosis including craniopharyngioma and Rathke’s cysts. Total surgical removal involving appropriate approach, based on size, is required for optic nerve decompression.

Our case raises awareness amongst endocrinologists regarding this rare and diagnostically challenging condition that may present with a spectrum of symptoms ranging from acute vision loss to mild pituitary dysfunction.