Microsatellite Instability in Medullary Carcinoma of the Colon

Abstract

Medullary carcinoma (MC) of the large intestine is a relatively new histological type of adenocarcinoma characterized by poor glandular differentiation and an intraepithelial lymphocytic infiltrate. MC can be associated to a defective mechanism for DNA mismatch repair, caused by the so-called microsatellite instability (MSI). We present the case of a 44 years old Caucasian woman, who referred to the Emergency Room with symptoms mimicking an acute appendicitis. Computed tomography and colonoscopy demonstrated an ulcerated and stenotic lesion of the caecum without signs of metastasis and peritoneal carcinosis. Patient underwent a laparoscopic right colectomy. The final pathologic findings provided the diagnosis of medullary carcinoma with MSI. Patient then underwent adjuvant chemotherapy according to the FOLFOX-4 protocol (association of 5-Fluorouracil, Leucovorin, and Oxaliplatin) for twelve cycles. At two-years follow-up, patient is disease free. MC in association with MSI is a non-frequent tumor of the colon characterized by a better prognosis compared to other types of poorly differentiated adenocarcinoma. In the observed case, 24 months after the surgical operation, the patient is in good health and there is no evidence of metastasis or relapse.

Diagnostic problems and immune contexture in a case of cecal medullary carcinoma

“…However, this could not be concluded from a single case and it could be of value to compare MC cases with different FOXP3 positive cell counts. In a recent published analogous to this case report [18] the clinical and histological findings were equivalent to those presented herein, having similar free of disease period (24 and 28 months, respectively) despite there being no post-surgical treatment in our case. However, the T-cell subgroups of the microenvironment were not mentioned in that case.…”

A case of poorly differentiated adenocarcinoma with lymphoid stroma originated in the ascending colon diagnosed as lymphoepithelioma-like carcinoma

“…The other type of the colorectal cancer with dense lymphoid stroma is medullary carcinoma (MC). Colorectal MC is a rare disease, only 10 cases reported in the literature to date; colorectal MC is almost always associated with a microsatellites instability-high (MSI-H) status [25][26][27][28][29][30][31][32][33] ( Table 2). Thirunavukarasu et al [34] reported that MC was a rare tumor, accounting for approximately 5-8 of every 10,000 colon cancers diagnosed.…”

Medullary Carcinoma of the Colon: A Histopathologic Challenge

“…MC is twice as prevalent in middle-aged women, favors the right side of the colon, and has a lower risk of lymph node metastasis than colon adenocarcinoma. MC can be poorly differentiated (72%) or undifferentiated (22%) with solid sheets of cells and excessive intraepithelial lymphocytic infiltration [ 2 ]. It does not have the glandular structure seen in adenocarcinoma [ 2 ].…”

“…MC can be poorly differentiated (72%) or undifferentiated (22%) with solid sheets of cells and excessive intraepithelial lymphocytic infiltration [ 2 ]. It does not have the glandular structure seen in adenocarcinoma [ 2 ]. Only a few cases of metastatic MC have been published in the literature [ 2 , 3 ].…”

“…It does not have the glandular structure seen in adenocarcinoma [ 2 ]. Only a few cases of metastatic MC have been published in the literature [ 2 , 3 ]. We present a rare case of MC, which was metastatic at presentation, and the diagnostic challenge it posed as the tumor cells lacked the usual markers for intestinal differentiation, such as cytokeratin (CK)20 and special AT-rich sequence binding protein 2 (SATB2).…”