Invasive giant pituitary macroadenoma causing Cushing disease; a case report

Abstract

Introduction: Cushing disease is a rare entity, and among them, giant pituitary adenomas causing Cushing disease is rarer. Here we present a case of Cushing disease secondary to a giant pituitary macroadenoma. Case report: A 41-year-old female with poorly controlled diabetes mellitus and hypertension diagnosed for six months presented with a history of unintentional weight loss, polyuria and polydipsia for the same duration. There was change in her facial appearance with increased pigmentation, frontal balding and she also noted increase in the size of her abdomen. There were features of proximal muscle weakness. Symptoms of hypothyroidism, hypoadrenalism or hyperprolactinemia were absent, and she was amenorrhoeic following hysterectomy done a year back. Visual impairment, headache, abdominal pain, features suggestive of internal malignancy, especially lung and renal, including features of pheochromocytoma were absent. She denied a family history of similar illness. Her BMI was 20.44 kg/m–2. She had a prominent abdomen, round facies, hirsutism, male pattern hair loss, facial plethora and generalized pigmentation and thinning of skin. She also had hypertension and proximal muscle weakness. Rest of the examination was normal. Investigations revealed hypokalaemia, poorly controlled hyperglycaemia and, non-suppressed overnight dexamethasone suppression test. She had a elevated ACTH level, and a high dose dexamethasone suppression test showed suppression. Pituitary imaging with MRI revealed a 51x 62x 41 mm size sellar and a para sellar mass with heterogeneous echogenicity extending to the right temporal lobe. Further imaging for ectopic ACTH secretion was negative.She underwent transcranial surgery which was unsuccessful due to intraoperative bleeding, and radiotherapy was given postoperatively. Conclusion: Cushing disease due to giant pituitary macroadenomas are rare and may require secondary therapeutic measures in controlling the disease in case of failed surgery.