Re-evaluating if observation continues to be the best management of idiopathic granulomatous mastitis

The presentation of idiopathic granulomatous mastitis can mimic breast cancer. Therefore, awareness of the condition is important for surgeons. The current series is the largest in a US population.

Retrospective chart review of patients treated at a county, safety-net hospital in Arizona. Cases were identified from January 2006 to January 2019. Sociodemographic information, clinical history, management, and outcomes were collected.

There were 145 occurrences of idiopathic granulomatous mastitis among 120 women. Most of the patients (92%) were of Hispanic ethnicity and born outside (87%) of the United States. The average age was 35 years. Nearly all patients (95%) were parous, with an average of 3 pregnancies. Most (88%) presented with a palpable mass, and more than half (54%) of these masses were painful. Six patients had prolactinomas or hyperprolactinemia, 11 patients were pregnant, and 5 were postpartum. Early in the time period studied, 6 patients underwent excision of the masses. The remaining 114 underwent planned observation after biopsy confirmation of the diagnosis. Two patients were lost to follow-up, and the other 112 patients with idiopathic granulomatous mastitis resolved spontaneously. Nineteen had more than 1 episode. Average time to resolution was 5 months (range 0-20). Adjusted log-normal regression analysis found that later age of first live birth was associated with greater time to resolution (P < .01).

Idiopathic granulomatous mastitis is a self-limited, benign condition that waxes and wanes and eventually resolves without resection. After diagnosis, medications are unnecessary, and operations can be limited to drainage procedures for fluid collections.