Idiopathic Granulomatous Mastitis, Erythema Nodosum, and Polyarthritis

Abstract

Idiopathic granulomatous mastitis (IGM) is an inflammatory-mediated rare disease that can be linked to rare manifestations. Erythema nodosum (EN) and polyarthritis, seen in a multitude of autoinflammatory and autoimmune diseases, have been rarely linked to IGM. Despite the cause of IGM being unclear, Corynebacterium infections are thought to play a role in the pathophysiology of IGM. Unusually, IGM has a relapsing and remitting course, which also applies to its systemic manifestations. As such, we present a case of IGM in a middle-aged lady who was initially thought to have Corynebacterium-containing unilateral abscesses for which drainage was performed. However, several abscesses devoid of bacterial growth started recurring, and the disease course was complicated by EN and polyarthritis. IGM, EN, and polyarthritis eventually resolved and were managed with symptomatic treatment.

Keywords: Corynebacterium; Idiopathic granulomatous mastitis; erythema nodosum; polyarthritis.

Figure 1.

Craniocaudal (A) and mediolateral oblique views (B) of the right breast show an area of increased density along the outer slightly lower quadrant of the right breast. Ultrasound (C) of this region showed an area of decreased echogenicity with areas of low-level internal echoes. Aspiration of the areas with low-level internal echoes revealed pus, which was sent for cytology and culture. Ultrasound of the right axillary region (D) showed a borderline 2 × 1 cm lymph node with 5 mm cortical thickening.

Figure 2.

Acute inflammation consisting of neutrophils with prominent vessels. Scattered eosinophils and lymphocytes are also seen. (Hematoxylin and Eosin stain, original magnification 40×).

Figure 3.

Raised erythematous spots on the anterior shins bilaterally.