Granulomatous mastitis co‑existing with breast cancer: A case report and mini‑review of the literature

Granulomatous mastitis (GM) is a rare inflammation of the breast marked by non‑caseating granulomatous lesions near the breast ducts and lobules. Reports of GM coinciding with breast cancer are rare. The present study describes the case of a patient with GM, high‑grade high‑grade ductal carcinoma <em>in situ</em> (DCIS), and invasive ductal carcinoma were present in the same breast. A 36‑year‑old woman with a 2‑week history of left breast pain was found to have a large, firm lump. A core needle biopsy led to the diagnosis of DCIS and suppurative GM. The patient was initially treated with analgesics and antibiotics for 20 days. Eventually, the patient underwent a complete mastectomy with immediate reconstruction using a TRAM flap. A subsequent histopathological examination revealed invasive ductal carcinoma of no specific type, poorly differentiated, with extensive DCIS and suppurative GM. Upon the last follow‑up, the patient was monitored and remained stable with no post‑operative complications. Furthermore, in a literature review conducted utilizing Google Scholar and PubMed, only 13 cases of the simultaneous presence of GM and breast cancer were found. The average age of these patients was 43.07&plusmn;12.10 years. Of note, 7 (53.85%) of these patients had both GM and breast cancer in the left breast, while only 2 cases (15.38%) involved the conditions in contralateral breasts. In conclusion, distinguishing between breast cancer and GM is challenging. Although the simultaneous presence of GM and breast cancer is rare, it remains essential to consider this possibility. However, further research is required to clarify the association between GM and breast cancer.