Prolactinoma is a rare tumor of childhood. Clinical presentations of prolactinoma include amenorrhea, delayed puberty, and galactorrhea. For the first time, in this case, elevated prolactin levels were associated with unexpected premature pubarche. We describe an 8-year, 7-month-old boy with acne and gradual appearance of pubic hair, corresponding to tanner stage 2. Hormonal tests showed severe hyperprolactinemia (prolactin = 246.8 μg/L and pooled prolactin = 175 μg/L and macroprolactin = 5 μg/L) and mildly elevated level of dehdroepiandrostenedion sulfate (DHEAS) and testosterone. Magnetic resonance imaging (MRI) findings confirmed the presence of a pituitary macroprolactinoma, measuring 14 mm × 12 mm × 8 mm on the right side of the pituitary gland. Cabergoline therapy was commenced (0.5 mg/week) and after 3 months, no evidence of pubarche progression was observed. Prolactin level and tumor size markedly reduced. At the 9-month follow-up visit, a normal MRI was reported. This case highlights that even when facing premature pubarche, careful examination is mandatory, and if no obvious etiology is found for premature pubarche, clinicians should consider prolactinoma.