Endocrine Abstracts

65-year-old lady presents to GP with 3-month history of fatigue, weight loss and nausea with background of stable Chronic Lymphocytic Leukaemia (CLL). GP started Levothyroxine 25 mg OD due to low T4 of 5.9 pmol/l (12-22) and low TSH of 0.25 mU/l (0.27-4.2). As she continued to feel tired, random cortisol was requested which was low at 25nmol/l leading to admission. Admission cortisol was 55nmol/l with an inappropriately normal ACTH of 11.6 ng/l (7.2-63.3). Pituitary profile showed evidence of panhypopituitarism with low LH 0.1IU/l (postmenopausal 15.9 - 54.0 IU/l), low FSH 5.1IU/l (postmenopausal 23.0 - 116.3 IU/l) and modest elevation of prolactin, possibly due to stalk effect, at 944 mU/l (102-496). She was started on IV Hydrocortisone (HC) and levothyroxine was increased to 50 mg OD. Pituitary MRI showed 12.3×12.3×12 mm lesion abutting the optic chiasm. Visual field assessment was normal. After review at pituitary MDT clinic, the outcome was to repeat MRI in 6 months to monitor progression. Repeat MRI revealed slight progression of the lesion and she opted to undergo transsphenoidal surgery. Histology and immunochemistry showed features consistent with CLL and no evidence of superadded pituitary adenoma. MRI at 3-, 6- and 24-months post-op showed no recurrence of CLL in the pituitary. She is under regular haematology follow-up and her CLL is stable. Hereby we report an exceedingly rare case of a patient with symptoms of panhypopituitarism with MRI findings of a pituitary lesion which later transpired to be CLL mimicking a pituitary macroadenoma. Central nervous system infiltration by CLL is unusual and involvement of the pituitary, to our best knowledge, has been reported in only a handful of cases. Our case adds to the limited literature of this extremely unusual occurrence. We conclude in any patient with CLL presenting with symptoms of hypopituitarism, one should consider CLL infiltration of the pituitary as a rare but possible differential diagnosis.