Erythema nodosum and granulomatous mastitis: Case study and discussion

Introduction: Erythema nodosum (EN) presents as tender, erythematous subcutaneous nodules generally located on the anterior aspect of the lower limbs. The most common identifiable cause for EN is streptococcal throat infection, but it can be a rare systemic manifestation of granulomatous mastitis (GM)1.
Case Study: An otherwise well 32 year old nulliparous women presented with a 1-month history of a spontaneous left breast mass. She had no family history of breast cancer or rheumatologic conditions, and was not on any medications. The patient went on to develop fevers, malaise, polyarthralgia and erythematous nodules on both her shins, which were biopsy proven to be EN. She was eventually diagnosed with GM secondary to tuberculosis (TB).
Discussion: The first case of EN associated with GM was described in literature in 1987, in which a patient presented with GM, EN, and monoarthritis simultaneously. Since this time, infrequent cases have been published in medical literature. In cases where EN and GM occur together, sarcoidosis and TB are reported to be the most common causative aetiology. However, EN can occur with idiopathic GN2.
Conclusion: EN may be associated with a wide variety of diseases, including those that are rarer such as GM. As such, diagnosis of EN must always be followed up by search for the underlying cause, which in some cases may be more sinister such as TB and sarcoidosis.
1. Requena L, Requena C. Erythema nodosum. Dermatology Online Journall. 2002[cited 8(1).
2. Adams DH, Hubscher SG, Scott DG. Granulomatous mastitis--a rare cause of erythema nodosum. Postgraduate Medical Journall. 1987[cited 63(741):581-2.

Dr. Sarath Bodapati