Endocrine Abstracts

Anterior pituitary hyperplasia is known to occur with primary hypothyroidism mimicing a pituitary tumour. Massive ovarian enlargement is sometimes associated with juvenile primary hypothyroidism but rarely reported in adults. We report a case of a 23-year-old female who presented with features of a pituitary macroadenoma and bilateral ovarian enlargement which regressed completely with thyroxine therapy.

A 23-year-old woman presented with nipple discharge, irregular menstruation, weight gain and progressive abdominal distension. On examination she had galactorrhoea, coarse dry skin and a firm pelvic mass. Visual fields were normal. Serum prolactin was 227 ng/dl (1.9–25), TSH >100 mIU/l (0.3–4.2) and free T4 2.9 ng/dl (5.1–14.1). MRI pituitary showed a lobulated intrasellar mass with suprasellar extension suggestive of a pituitary macroadenoma. Ultrasound pelvis revealed multiloculated thin septal cystic lesions in both adenexial regions with no separate ovarian tissue identified.

Profound hypothyroidism accounting for the above findings was considered and she was commenced on levo thyroxine 100 mic/dl. Her symptoms progressively resolved with time. Thyroid function tests were normalized after 3 months and prolactin after 8 months. MRI scan pituitary returned to normal within 8 months and ultrasound pelvis within 6 months.

Pituitary hyperplasia is known to occur in primary hypothyroidism due to hyperplasia of both thyrotropes and lactotropes caused by TRH stimulation. This may appear as a ‘pitiutary pseudotumour’. Massive cystic ovarian enlargement with primary hypothyroidism is commoner in longstanding juvenile hypothyroidism, due to unusually high levels of TSH which have weak FSH like activity.

This case illustrates how pituitary enlargement mimicking a macroadenoma and massive ovarian enlargement can occur with profound hypothyroidism with complete regression following thyroxine therapy. Awareness that ovarian and pituitary enlargement can be caused by severe hypothyroidism may spare patients from unnecessary surgical interventions.