Idiopathic Granulomatous Mastitis Associated with Erythema Nodosum in a Pregnant Woman.

A 32-year-old woman at 17 weeks' gestation presented with fever and a 1-week history of an acute nodular eruption involving her legs, along with bilateral ankle and knee pain. She also had had a recurrent right breast abscess for 2 months for which she had been treated with oral antibiotics and surgical drainage, but with slight improvement. Cultures of the abscess showed no bacteria or fungi. She had no history of tuberculosis, sarcoidosis, trauma to the breast, or a family history of breast pathology. Cutaneous examination revealed multiple, tender, erythematous, subcutaneous nodules on her legs (Figure 1) and an ill-defined tender mass involving the inferior quadrant of the right breast without nipple discharge or retraction. There was a scar with drainage on her right breast (Figure 2). There were no regional lymphadenopathies. Left breast and left axilla examination was unremarkable. Significant laboratory findings included an erythrocyte sedimentation rate of 54 mm/hour (normal levels [NL] < 20 mm/hour), an elevated C reactive protein at 148 mg/L (NL < 5 mg/L), and a high level of white blood cells averaging 15,000 elements/mm³ (NL < 10,000/mm³).