Background: Granulomatous lobular mastitis (GM) is a rare inflammatory breast disease. Reports focusing on GM caused by antipsychotic-induced hyperprolactinemia (HPRL) are very rare. Aim: To report a study of GM associated with antipsychotic-induced HPRL and discuss the mechanism and management. Materials and Methods: A retrospective review of patients with GM and psychiatric disorders were carried out. The clinical characteristics, management and outcome were collected and analyzed. The relationship between antipsychotics and GM was evaluated using the Naranjo Adverse Drug Reaction Probability Scale (Naranjo scale). Results: Nineteen female GM patients with psychiatric diseases, aged 21-39 years, who had received antipsychotics for 0.5-10.2 years were included. Most patients took multiple antipsychotics, and 10 (52.6%) took risperidone-containing regimens. Increased prolactin (PRL) was detected in all patients (range 35.15-200 ng/mL). The scores of Naranjo scale were 7-8, indicated the antipsychotics probably induced GM. All patients received systemic therapy, and were prescribed bromocriptine. Seven patients (36.8%) decreased the dose of antipsychotics, six (31.6%) switched antipsychotics, three (15.8%) continued the primary antipsychotics, and three (15.8%) discontinued antipsychotics. In addition, 14 patients (73.7%) received corticosteroid, 4 (21.1%) received antimycobacterials. PRL decreased to normal in 1 month. Seven patients (36.8%) received excisional surgery. After 12 months' follow-up (range 9-56 months), only three patients (15.8%) had a recurrence. Conclusion: Long-term use of antipsychotics may increase PRL levels, and lead to GM. It is vital to assess PRL level and reduce PRL to normal in patients with GM.
Keywords: Naranjo Adverse Drug Reaction Probability Scale; antipsychotic agents; granulomatous lobular mastitis; hyperprolactinemia; prolactin.