A case report of Mucocele-like Lesion (MLL) of the breast

The Rosen report states that the Mucocele-like Lesion (MLL) of the mammary gland is a benign little known condition analogous to mucocele of a minor salivary gland. Recently we had an opportunity to investigate and report on the cytological structure of MLL in a 27-year-old female patient. As a result we found that it is relatively difficult to distinguish MLL from mucinous carcinoma using breast aspiration cytology and, in the early stage of mucinous carcinoma, we came to believe that it would be relatively difficult to make an unequivocal diagnosis using histological examination. Though it has often been reported that mucinous background with relatively bland cells is an aid to the diagnosis of mucinous carcinoma, we believe that the cytologist must bear in mind the existence of benign MLL and use extreme caution when observing the cytological evidence. Clinically speaking, MLL tends to occur in pre-menopausal women younger than the age with which the occurance of mucinous carcinoma is usually associated. This clinical factor may be helpful in the actual diagnosis and subseqent treatment of MLL.