Hyperprolactinemia is a rare entity in the pediatric population. The most common causes of hyperprolactinemia include drug use, hypothyroidism and renal insufficiency, though rarely a pituitary or sellar mass is discovered. We present an immunocompetent pediatric patient who presented with gynecomastia and was found to have hyperprolactinemia. Imaging showed a sphenoid mass and referral was made for a pituitary tumor. The mass was not a pituitary tumor and he was formally diagnosed with allergic fungal sinusitis and treated surgically. There are no previous reports of allergic fungal rhinosinusitis causing pituitary dysfunction in a pediatric patient. We also present a brief review and discussion of the treatment of allergic fungal sinusitis.