Invasive cystic hypersecretory ductal carcinoma of breast: a case report and review of the literature.

c Few individual cases of invasive cystic hypersecretory ductal carcinoma of the breast have been described. Review of 33 cases of cystic hypersecretory carcinoma, including the current case, indicate that only 6 cases presented with invasive disease. Two of these cases had positive nodes and 2 had distal metastases. The case presented here is unique in an additional aspect: the contralateral breast harbored lobular breast carcinoma 10 years after mastectomy of the first malignancy. Bilateral breast disease resulting in bilateral mastectomies over long-term followup, as in the case presented here, was reported in 3 of 33 cases. (Arch Pathol Lab Med. 1999;123:1108‐1110) C ystic hypersecretory carcinoma of the breast is a rare breast lesion. The characteristic histologic features are cystic dilatation of ducts and acini filled with thyroid colloid‐like eosinophilic material. Micropapillary protrusions with cytologic atypia are required for the diagnosis of cystic hypersecretory carcinoma, and invasion of surrounding stroma, not merely spilling of cyst contents, is needed for diagnosis of invasion. Of the 32 cases reported to date, only 5 belonged to the invasive group. We report an additional case of invasive cystic hypersecretory carcinoma, in which lobular carcinoma appeared in the contralateral breast 10 years after mastectomy for hypersecretory carcinoma. The relevant literature is reviewed and discussed.