Endocrine Abstracts

Giant prolactinomas are very rare and constitute 2-3% of all lactotroph PitNETs with male preponderance. We present a case series of five male patients with giant prolactinomas with various clinical presentation.

Case 1: A 66-year-old male hospitalized due to left peripheral facial palsy. In computer tomography (CT) pituitary mass (41 x 43 x 64 mm) invading cavernous/sphenoid sinuses/carotid arteries/optic chiasm was visualized. Bitemporal hemianopia/headaches/decreased libido were observed. Prolactin level was 22083 uIU/ml (N: 86-324 uIU/ml). Cabergoline up to 1 mg/week was implemented. After 3 months, regression of pituitary tumor by 14 mm and normal range prolactin level were observed. Milder headaches and improvement of visual field were reported.

Case 2: A 62-year-old male presented with life-threatening panhypopituitarism/diabetes insipidus at the age of 52. In MRI pituitary tumor 36 x 62 x 35 mm with extrasellar extension/optic chiasm compression/invading third ventricle was found. Prolactin level was 223549 uIU/ml. Despite dopamine agonist treatment (bromocriptine 22.5 mg/day and cabergoline 1.5 mg/week) progression of pituitary tumor/high prolactin level were observed. In 2016 patient did not consent to neurosurgery. Short-acting somatostatin analogues was introduced. In 2019, significant visual filed deterioration was observed- patient consent to craniotomy. Histopathology revealed lactotroph-PitNET with Ki67>3%. After 6 months, tumor progression was noted. Patient was disqualified from radiotherapy. Temozolomide (200 mg/m² per 5 days every 28 days) was introduced. After 9 cycles, regression of pituitary tumor was observed and decrease of prolactin level by 2600%.

Case 3: A 56-year-old male was hospitalized due to syncope. In CT pituitary tumor 40 x 30 mm was diagnosed with bitemporal hemianopsia. Prolactin level was 10446 uIU/ml. Cabergoline(1 mg/week) was implemented. After 3 months, regression of pituitary tumor (21 x 26 x 19 mm)/normal prolactin level/improvement of vision were noted.

Case 4: A 23-year-old male presented with severe headaches and visual impairment at the age of 21. In MRI pituitary mass 52 x 52 x 41 mm with extrasellar extension was found. Prolactin level was 21522uIU/ml. Insufficiency of thyroid and gonadal axis was diagnosed. Cabergoline was implemented (4 mg/week) with regression of the tumor (25 x 13 x 23 mm), decrease of prolactin level (8400uIU/ml) and complete remission of headaches. Cabergoline was decreased to 2 mg/week.

Case 5: A 67-year-old male diagnosed with a pituitary tumor (65 x 35 x 40 mm) at the age of 50 years. Due to hyperprolactinemia, cabergoline was implemented (7 mg/week). After few weeks, pituitary apoplexy occurred. Patient underwent emergency neurosurgery. Insufficiency of thyroid, adrenal and gonadal-axis appeared. MRI over next 20 years demonstrated stable residual tumor(22 x 28 x 11 mm). Patient is now treated with 0.25 mg of cabergoline/week. The management of giant prolactionomas in men is challenging. Studies on prognostic factors of the efficient treatment in prolactinomas are needed.