Broad clinical spectrum and diverse outcomes of prolactinoma with pediatric onset: medication-resistant and recurrent cases.

Prolactinoma is a benign tumor of the pituitary gland that rarely occurs in children and adolescents; thus, the clinical spectrum and long-term prognosis in these patients remain unknown. This study was performed to investigate the long-term outcomes of medical treatment and the prognostic factors for remission and relapse in children and adolescents with prolactinoma. Three male subjects and four female subjects between the ages of 7- and 17-years-old were included in this study. The mean initial serum prolactin level was 443 ± 251.8 ng/mL (range, 152-946 ng/mL). During the follow-up period (range, 0.6-20 years), a dopamine agonist was administered, and surgery or radiotherapy was performed in cases of resistance to medical treatment or relapse. Unlike female subjects with macroadenoma who often exhibit a good clinical course, two male subjects with early onset macroadenoma presented with visual disturbances. These subjects showed resistance to medical therapy and relapsed, eventually requiring surgical removal and radiotherapy; one of the subjects manifested a metastatic thrombus in the internal jugular vein. In conclusion, pediatric prolactinoma exhibits a broad clinical spectrum, a relatively high incidence of macroadenoma, resistance to medical therapy, and frequent tumor relapses. In addition, a poor prognosis appears to be correlated with male sex, age at disease onset, and histopathological characteristics.