Introduction: Giant prolactinomas represent 2–3% of prolactin-secreting pituitary adenomas and show a male predominance. They present with mass effect symptoms and hypogonadism, but may be overlooked, leading to delayed diagnosis. Although dopamine agonists are first-line therapy, management remains challenging due to the large size and invasive behavior. This study aims to describe the clinical and radiological features, treatment modalities, and outcomes of three cases of giant prolactinomas. We retrospectively reviewed three men with giant prolactinomas, including their clinical, biochemical, and radiological features, along with treatment and outcomes. Cases: Three male patients aged 35–59 years with giant prolactinomas were included. Two patients presented with visual disturbances, headache, and features of hypogonadism, while one patient had acute confusion and visual loss secondary to obstructive hydrocephalus requiring ventriculoperitoneal shunt insertion. Imaging in all cases demonstrated large invasive pituitary macroadenomas with extensive local extension. Baseline serum prolactin levels were markedly elevated, ranging from 86,568 to 441,116 uIU/mL (86–324 uIU/mL). All patients had secondary hypogonadism, while secondary hypothyroidism and hypocortisolism were each identified in two patients. One patient also had poorly controlled diabetes mellitus at presentation. Dopamine agonist therapy was initiated as the primary therapy for all the patients. Two patients developed cerebrospinal fluid leak following initiation of low-dose dopamine agonist therapy (one patient received cabergoline 0.25 mg weekly, while another received 0.5 mg weekly), which resolved spontaneously with conservative management. Serum prolactin levels decreased markedly, with significant improvement in symptoms related to mass effect following treatment. Conclusion Giant prolactinomas may present with significant mass effect and multiple pituitary hormone deficiencies. Dopamine agonists remain the cornerstone of management and can result in substantial biochemical and clinical improvement even in large invasive tumors. However, rapid tumor shrinkage may lead to complications such as cerebrospinal fluid leak, highlighting the importance of close monitoring during treatment initiation.
Prolactinoma