A 61-year-old woman was hospitalized with a 5-week history of abdominal discomfort, change in bowel habits, and weight loss. Colonoscopy showed a protruded tumor of the sigmoid colon first diagnosed as undifferentiated carcinoma. Surgical resection of the sigmoid colon was performed. Histological examination of the surgical specimen showed a proliferation of basaloid cells arranged in tumor clusters with central comedonecrosis and peripheral palisading of the nuclei. The tumor invaded the subserosa and presented liver metastasis without lymph node metastases. The tumor cells were marked by keratin AE1/AE3, keratin 5/6, epithelial membrane antigen, bcl-2, vascular endothelial growth factor, CD105, neuron-specific enolase, MLH-1, MSH-2, and p53, and were negative for keratin 7/20, chromogranin, synaptophysin, carcinoembryonic antigen, p63, c-KIT, and maspin. A high p53 nuclear index was also detected. On the basis of these characteristics and molecular examinations, the final diagnosis was microsatellite stable/human papilloma virus-negative/K-ras mutated/BRAF wild-type basaloid carcinoma (BC). Only seven BCs of the colon were reported in the literature, this being the eighth one and the first case that reports new molecular findings about microsatellite instability, K-ras/BRAF mutations, angiogenesis, and maspin expression in BC, with direct involvement in targeted therapy.
Departments of aPathology
bSurgery, University of Medicine and Pharmacy of Tirgu-Mures, Tirgu Mures
cDepartment of Pathology, County Hospital of Miercurea-Ciuc, Miercurea Ciuc, Romania
dCenter of Tumors, National Institute of Oncology, Budapest, Hungary
Correspondence to Simona Gurzu, MD, PhD, Department of Pathology, University of Medicine and Pharmacy of Tirgu-Mures, 38 Ghe Marinescu Street, 540139 Tirgu Mures, Romania Tel: +40 745 673 550; fax: +40 265 210 407; e-mail: firstname.lastname@example.org
Received December 19, 2013
Accepted January 21, 2014