41 Unexpected While Expecting: Rare Case of Pregnancy Associated Xanthogranulomatous Mastitis Masquerading as Malignancy

Background

Xanthogranulomatous inflammation is a rare inflammatory process in which lipid-laden macrophages aggregate in tissues. Data are limited to case reports, and there are no consensus guidelines on management. Here we report the first case of xanthogranulomatous mastitis (XGM) in a pregnant patient and present a literature review on presentation and management of XGM.

Materials and Methods

We conducted a retrospective chart review of a case of XGM in a pregnant patient and queried the English language literature database PubMed to identify studies on XGM. The search included the keywords and combinations: xanthogranulomatous or xanthogranuloma and breast or mastitis. Articles discussing breast implants were excluded.

Results

A 38-year-old female at 37-weeks’ gestation presented with right breast swelling and pain. Ultrasound suggested an abscess, which was treated with drainage and antibiotics. Repeat ultrasound showed a Breast Imaging Reporting and Data System (BI-RADS)–4 lesion with a 2.7 × 1.8–cm lesion. Biopsy revealed xanthogranulomatous inflammation, negative for malignancy. She was able to continue with lactation. The patient had recurrence 3 months later with a persistent 2.5-cm mass on ultrasound and proceeded with surgical excision. Pathology demonstrated fragmented abscess cavity with no evidence of malignancy. There was no recurrence at 6 months follow-up.

We found 8 PubMed indexed articles discussing XGM, excluding cases associated with breast implants. Twenty-four cases were reported across 8 articles. Six patients presented with a palpable mass, of which 4 reported tenderness (Table). BIRADS-3 lesions were reported in 9 patients, BIRADS-4 in 7, BIRADS-2 in 2, BIRADS-5 in 1. Twenty patients were treated with excision; 1 patient was treated with conservative management with antibiotics and follow-up biopsies. Three patients were found to have malignant or premalignant lesions, of whom 2 patients had invasive ductal carcinoma and 1 had ductal carcinoma in situ.

Conclusion

This is the first reported case of XGM in a pregnant patient. Avoiding up-front excision allowed the patient to avoid surgery while pregnant and breastfeed for 3 months. There was no malignancy on pathology, in line with the low co-incidence of malignancy in the literature reviewed. Initial conservative management with biopsy plus close clinical and imaging follow-up may help avoid unnecessary surgical intervention. This is critical in patients for whom excision poses additional risk, such as the pregnant patient. The paucity of PubMed-indexed literature on this topic shows that this is a promising topic for future study.