The needle core biopsy is a technique applied to remove small cylinders of breast tissue. The development of accurate radiological techniques for location of breast lesions has spread the use of core biopsy as the first histological approach to non-palpable lesions. The differential diagnosis of mucinous carcinoma and benign mucinous lesions by core biopsy may be challenging, mainly when the lesion shows mucin extravasation. The accuracy of diagnosis in these cases is extremely important to determine the type of procedure to be performed, as well as the treatment choice. This study shows a review and an update of the literature as to invasive mucinous carcinoma of the breast and its differential diagnosis, with emphasis on the challenges of diagnosis by core biopsy. Among the differential diagnoses are fibrocystic changes with luminal mucin, mucinous papillary lesions, mucocele-like lesions that range from benign to those associated with atypical ductal hyperplasia and ductal carcinoma in situ. Mucinous changes may also be found in a variety of lesions such as fibroadenoma, phyllodes tumor, pleomorphic adenoma and nodular mucinosis. In conclusion, core biopsy is a reliable technique for the diagnosis of mucinous carcinoma of the breast and its differential diagnosis, however, in doubtful cases or when the sample is scarce, it is advisable to perform an excisional biopsy to clarify the diagnosis.
Breast; Core biopsy; Mucinous carcinoma; Mucinous lesions; Differential diagnosis
