Endocrine Abstracts

JOINT2394

Introduction: Giant prolactinomas, defined as prolactin-secreting adenomas larger than 4 cm, are rare and often present with significant compressive symptoms due to their invasive nature. They pose major diagnostic and therapeutic challenges, particularly in male patients, where late presentation is common. This case illustrates the aggressive evolution and management difficulties associated with giant prolactinomas.

Observation: We report the case of a 31-year-old male with no prior medical history, admitted for the management of a large pituitary adenoma. His symptoms began two months before hospitalization, with progressive headaches and bilateral visual impairment leading to complete blindness. Initial brain imaging (CT and MRI) revealed an invasive sellar and suprasellar mass (50 mm), extending into the cavernous sinuses, sphenoid, ethmoid, and nasal cavities, with compression of the optic pathways. The prolactin level was 138.5 ng/ml. On clinical examination, the patient was overweight (BMI = 26.53 kg/m²) with normal blood pressure (110/80 mmHg). Neurological assessment revealed bilateral areflexic mydriasis due to oculomotor nerve (CN III) involvement, along with bilateral optic atrophy confirmed by ophthalmologic evaluation. Visual field testing showed light perception in the right eye and complete blindness in the left. There were no motor or sensory deficits. Endocrine evaluation revealed signs of thyrotropic insufficiency (fatigue, psychomotor slowing, constipation) and corticotropic insufficiency (asthenia, anorexia). The patient was initially treated with cabergoline (0.5 mg/week for three months); however, no clinical or radiological improvement was observed. He subsequently underwent transsphenoidal endoscopic surgery, with histopathology confirming an invasive prolactin-secreting adenoma. The Ki-67 proliferation index was 2%. Despite surgical intervention, his condition worsened, with a rapid increase in tumor size (80 × 70 × 60 mm) and extensive skull base destruction noted on follow-up MRI. Biochemical evaluation confirmed corticotropic and thyrotropic insufficiencies, requiring hormonal replacement therapy. Cabergoline was continued with dose escalation up to 2 mg/week, but prolactin levels continued to rise, reaching 850.8 ng/ml at 12 months. Radiotherapy was indicated but could not be initiated due to the patient’s deterioration. Unfortunately, he passed away 18 months after diagnosis.

Discussion: Giant prolactinomas in men often exhibit an aggressive course with significant resistance to dopamine agonists, particularly in invasive forms. This case highlights the challenges of managing such tumors, including the need for multimodal therapy involving high-dose dopamine agonists, surgery, and potentially radiotherapy. Delayed diagnosis contributes to poor prognosis, emphasizing the need for early detection and long-term follow-up.