title: Invasive micropapillary component and its clinico-histopathological significance in patients with colorectal cancer.
abstract: Micropapillary components are located in distinct, empty spaces resembling lymphatic vessels and consist of clusters of cancer cells that adhere tightly to one another. These structures do not have a fibrovascular core. Invasive micropapillary components (IMPCs) exhibit reverse polarity, which results in a characteristic 'inside-out' structure. The aim of the present study was to examine the histological significance of the micropapillary component in colorectal carcinoma compared with conventional colorectal adenocarcinoma. Among 115 patients, 5 (4.3%) were diagnosed with a micropapillary colorectal component based on hematoxylin and eosin staining and immunohistochemical analysis. To exclude identification of poorly-differentiated clusters of adenocarcinoma cells in the lymphatic vessels, immunohistochemical analysis with D2-40 was performed, and epithelial membrane antigen was used to confirm the specific 'inside-out' structure of IMPCs. IMPCs were observed to positively correlate with histopathological type (P=0.001) and tumor invasion in venous vessels (P=0.033). Furthermore, the presence and number of lymph node metastases was greater in IMPC cases compared with conventional carcinoma cases; however, these differences were not statistically significant (P=0.087 and P=0.094, respectively). In addition, IMPC cases were not significantly associated with the presence of inflammatory infiltrate in the invasive front of the tumor (P=0.098). Therefore, the present study indicates that the IMPC serves a histopathological and prognostic role in the diagnosis of colorectal cancer due to its aggressive and invasive behavior. IMPC is rare in cases of colorectal cancer and remains a great diagnostic challenge in pathomorphology with further detailed investigation required in the future.
authors.affiliation: Department of General Pathomorphology, Medical University of Białystok, Białystok, 15-269 Podlaskie, Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Jakubowska
authors.affiliation: Department of General Pathomorphology, Medical University of Białystok, Białystok, 15-269 Podlaskie, Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Guzińska-Ustymowicz
authors.affiliation: Department of General Pathomorphology, Medical University of Białystok, Białystok, 15-269 Podlaskie, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Pryczynicz
keywords: colorectal cancer; invasive micropapillary carcinoma; micropapillary component