Giant pituitary adenoma.

To cite: Leão RN, Baptista JT, Ribeiro JV. BMJ Case Rep Published online: [please include Day Month Year] doi:10.1136/bcr-2013202041 DESCRIPTION A healthy 68-year-old man presented in the emergency room with a sudden episode of headache and vomiting together with disequilibrium and crural paresis. The laboratory evaluation revealed hyponatraemia (Na+115 mEq/L). Head MRI demonstrated a giant 40×25×31 mm pituitary lesion (figures 1 and 2). Laboratory studies revealed growth hormone (GH) 0.1 ng/mL (0.06–5), follicle-stimulating hormone (FSH) 14.5 mUI/mL (0.7–11.1), luteinising hormone (LH) 1.9 mUI/mL (0.8–7.6), prolactin 23.1 ng/mL (2.5–17), low free thyroxine (fT4) 0.4 ng/mL (0.8–1.9), thyroidstimulating hormone (TSH) 7.88 mUI/mL (0.4–4), cortisol 2.4 μg/dL (5–25), adrenocorticotropic hormone (ACTH) 9.26 pg/mL (<46), insulin-like growth factor-1 (IGF1) <25 ng/mL (69–200), testosterone <0.04 ng/mL (5.6–19) and sex hormone binding globulin (SHBG) 30 nmol/L (13–71). The cerebral lesion was surgically removed by a trans-sphenoidal approach and the histopathological evaluation has revealed pituitary adenoma (PA) producing gonadotropic hormones (figures 3–5). Currently, the patient is completely recovered. At the third month postsurgery, laboratory studies revealed GH, FSH, LH, cortisol, ACTH, IGF1, testosterone and SHBG were normal; TSH 4.3 mUI/ mL, fT4 0.6 ng/mL. The patient is currently under medical treatment with levothyroxine (100 mg/day) without other hormonal replacement therapies. Also, due to the risk of removing normal functioning pituitary tissue, he was started on corticosteroid treatment in the preoperative period during the first month. A subsequent head MRI is scheduled for the sixth postsurgical month, to assess any eventual residual adenoma. The PA is a benign tumour diagnosed in 15–20 million individuals a year. It is responsible for 10–15% of intracranial tumours. PA is classified as a macroadenoma if it has a diameter of ≥10 mm and as a giant adenoma if the diameter is ≥40 mm. Symptoms depend on the size, mass effect and hormonal dysfunction. Gonadotropic adenomas comprise 10% of PAs and are generally defined as non-functioning adenomas. Symptoms and signs are usually related with mass effect requiring high clinical suspicion for an early diagnose. The most common symptom is impaired vision (caused by compression of optic chiasm). However, its onset is gradual. In this particular case, despite the size of the adenoma and compression of the optic chiasm, the patient did not have any visual deficit. In some cases, as in ours, endocrine testing reveals hyperprolactinaemia, which is due to compression of the pituitary stalk. The majority of the cases present hypopituitarism caused by the compression of normal pituitary cells. Generally, the levels of gonadotropins are low, ending up in