CSF Rhinorrhea: An Early Complication of Dopamine-Sensitive Macroprolactinoma

ABSTRACT Objective: Cerebral spinal fluid (CSF) leak is a known surgical complication of invasive macroprolactinomas. Case reports suggest this complication can occur with dopamine agonist treatment alone. Methods: We present clinical features, imaging, and biochemical characteristics of one such case of an invasive macroprolactinoma complicated with early CSF leak. Results: A 35-year-old obese male presented with weight gain of over 100 pounds within the last year and absent morning tumescence. Laboratory evaluation was notable for elevated total prolactin (PRL) (4,655 ng/mL) and low total testosterone (24 ng/dL). Magnetic resonance imaging (MRI) revealed a large pituitary adenoma (4.2 × 2.5 × 3.5 cm) extending into the cavernous and sphenoid sinuses, partially eroding the sphenoid bone. Dopamine agonist, cabergoline 250 μg twice/week was started. After two doses, the patient developed CSF rhinorrhea and was hospitalized. Adenoma was smaller in size (4.1 × 1.9 × 3.3 cm), and total PRL declined to 824 ng/mL. An endoscopic subtotal resection of adenoma with CSF leak repair was performed. Treatment with cabergoline was continued, resulting in complete resolution of CSF leak within a few days. Two months later, cabergoline dose was increased to 500 μg twice a week as adenoma size remained unchanged. One month later, MRI showed regression of the pituitary tumor with cystic changes. Serum PRL level substantially declined (total PRL, 102 ng/mL). Conclusion: Clinicians should be highly observant of and educate patients about CSF rhinorrhea as potential early consequence of medical therapy of macroprolactinoma to avoid misdiagnosis and fatal sequelae of this complication. Abbreviations: CSF cerebral spinal fluid; DA dopamine agonist; MRI magnetic resonance imaging; PRL prolactin