Granulomatous mastitis masking ductal carcinoma in situ: A case report with literature review

Granulomatous mastitis (GM) is a rare inflammatory disorder that infrequently occurs with synchronous breast carcinoma. The present study reports the case of a patient who was initially diagnosed with recurrent GM, which eventually proved to be masking an underlying ductal carcinoma in situ (DCIS). A 30-year-old female presented with left breast pain. On clinical examination, there was a large, palpable and painful lump in the left breast, with axillary lymphadenopathy. Initially, the diagnosis was GM and conservative treatment was applied. Surgical resection was decided upon for the condition after it became recurrent, and the histopathological examination revealed extensive DCIS with GM. Later on, the patient underwent a mastectomy with an axillary sentinel lymph node biopsy. The postoperative follow-up was uneventful. In conclusion, tissue diagnosis has a key role in detecting DCIS masked by GM, especially in young females who are not undergoing regular mammogram screening. The present study shows the challenge that the specialists in this field may face when dealing with recurrent GM of the breast, and warns them to search for a second pathology such as the DCIS presented in the current case.