[Immunohistochemical analysis of mismatch repair proteins in colorectal adenomas]

The deficiency of mismatch repair system is one of the main pathways in colorectal cancer. This system consists mainly of four proteins: MLH1, MSH2, MSH6 and PMS2. Colorectal cancer develops in the majority of cases from precancerous lesions called adenomas. Only few studies have reported on the deficiencies of these proteins in adenomas. In this study we used immunohistochemistry staining in colorectal adenomas to assay functional status of MLH1, MSH2, MSH6, and PMS2 proteins. 102 adenomas from 93 patients were collected in our institution during six years [2007-2012]. The immunohistochemical technique was performed with 4 antibodies: MLH1, MSH2, MSH6 and PMS2. The loss of expression was retained if adenomatous cells were not stained with positive internal control. Staining was considered as abnormal if nucleus of adenomatous cells showed low nuclear staining and / or heterogeneous one, while positive internal control had normal staining. Loss of expression of MSH2 and MSH6 in adenomatous cells was found in only 1 case which was a tubular adenoma 3mm high-grade dysplasia. Abnormal staining of the adenomatous cells was noted in 23 cases [22.5%] for MSH2 and in 8 cases [7.8%] for MSH6. No cases showed loss of expression of MLH1 and PMS2. Abnormal expression of MSH2 and MSH6 was not correlated with sex of patients, the location of the adenoma, its grade of dysplasia and its histological type. Loss of Mismatch repair proteins expression is a rare event in adenomas. However, the abnormal expression levels are higher in our study compared to those reported in the literature. This could reflect a higher rate of microsatellite instability in our patients. Multicenter and larger studies with molecular biology techniques are needed

aggressive course of de novo ulcerative colitis after renal transplantation: colonic adenocarcinoma with choriocarcinomatous differentation

A rare case of colonic carcinoma arising in de novo ulcerative colitis after renal transplantation in a 42-year-old woman is reported. Clinically, the patient presented ulcerative colitis 8 years after renal transplantation, developed colonic cancer with liver metastasis 2 years later and died one month post operatively. Histologically, the removed tumor was composed of two distinctive elements consisting of adenocarcinoma and choriocarcinoma. The metastatic foci in the liver were composed exclusively of choriocarcinoma. Identification as choriocarcinoma was made on the basis, of typical histological appearance, immunohistochemical demonstration of human chorionic gonadotropin [hCG] in the tumor cells and the high serum hCG level, unrelated to trophoblastic disease. In this report, pathogenesis is briefly discussed and clinical conditions are reviewed. In conclusion, the issue of de novo UC after organ transplantation is still a matter of debate. Further investigations are necessary to understand the tumorogenesis of colorectal cancer in de novo UC after renal transplantation

[Infantile desmoplastic fibroma of the maxilla]

Infantile desmoplastic fibromatoses are benign fibrous tissue tumours, non -metastasizing but locally aggressive and with high likelihood of recurrence. Many cases occur in young children between 18 months and 3 years and commonly present as painless mass of the submandibular region. The maxilla is rarely involved. Through this report and a review of literature, we are going to study clinical, pathological and prognostic characteristics of this affection. We report here a case of an aggressive desmoplastic fibroma arising in a 20-months-old infant originating in the left anterior maxillary wall. Clinical examination of the face revealed a non tender, firm, expansion of the left maxilla of 2.5 cm of diameter. The diagnosis of DF of the maxilla was made on the basis of histological features on biopsy specimen. No other location of the fibromatosis was found. The child had a favourable course. DF is an intraosseous, non metastasizing and locally aggressive fibrous tumour. Although its benignity it could engage vital prognosis since it can extend into vital organs