1Department of Pathology, Gangneung Asan Hospital, University of Ulsan College of Medicine, Gangneung, Korea. firstname.lastname@example.org 2Department of Surgery, Gangneung Asan Hospital, University of Ulsan College of Medicine, Gangneung, Korea.
Micropapillary carcinoma (MPC) is a rare variant of carcinoma, and it is composed of small papillary neoplastic cell clusters lying within clear lacunar spaces that simulate lymphovascular channels. This tumor has been described in the several organs such as the breast, lung, urinary bladder and salivary gland and it is known to be frequently associated with a high incidence of lymphatic invasion and metastasis in lymph nodes, resulting in poor clinical outcome. We present here a case of MPC in the gall bladder, and this type of case has not been previously described. Histologically, the tumor was composed of micropapillary carcinoma with tight clusters of micropapillary aggregates in the background of tubular adenoma. Focal invasive micropapillary components were also noted in the submuscular connective tissue. A metastatic lesion in a regional lymph node also showed an entirely micropapillary pattern.