Charcoal granuloma mimicking breast cancer: an emerging diagnosis

BACKGROUND: Image-guided charcoal injection in suspicious breast lesions for preoperative localization is a procedure that has been increasing over the years because it is safer, faster, and more affordable when compared to needle-wire preoperative localization. To date, no complications have been associated with the method. However, in recent years there have been some reports about charcoal granulomas mimicking malignant lesions in some postoperative patients or in a conservative follow-up. PURPOSE: To report a series of 11 cases which had suspicious imaging findings for malignancy and resulted in charcoal granulomas on histopathological analysis. MATERIAL AND METHODS: A database of 1650 patients that attended our center from January 2007 to June 2018 was reviewed and detected 495 patients who had been previously submitted to ultrasound-guided charcoal marking in a breast lesion. Then, patients whose imaging studies were compatible with new suspicious lesions on mammography, breast ultrasound, and/or magnetic resonance imaging and biopsy of this new lesion indicating charcoal granuloma were selected. RESULTS: From 495 patients who had undergone charcoal localization injections in previous biopsies, we selected 11 who had new lesions with malignant characteristics on imaging studies but histopathological analysis resulted in charcoal granuloma. CONCLUSION: Charcoal granuloma should be considered in patients with previous preoperative injection localization, since the residual charcoal in the breast tissue may form granulomas and mimic malignant lesions on follow-up imaging studies.