IntroductionColorectal medullary carcinoma (MC) is a rare subtype of poorly differentiated adenocarcinoma (PDA) with unclear prognostic significance. Microsatellite instable (MSI) colorectal carcinomas have demonstrated better prognosis in clinical stage II.AimTo analyze the survival and clinicopathological characteristics of MCs versus PDAs with MSI in clinical stage III.Material and methodsWe studied 22 cases of PDAs with MSI versus 10 MCs.ResultsOf the 10 MCs, 7 patients were men; the mean age was 57.8 ±5.6 years. The mean tumor size was 9.6 ±4.1 cm, and the primary site was the right colon in 9; 7 patients showed lymph node metastases (LNM) and lymphovascular invasion (LVI). Of the 22 PDA cases, 12 (54.5%) were women with a mean age of 75 ±16.1 years. The mean tumor size was 6.4 ±3.2 cm. Twelve (54.5%) presented in the right colon, 21 (95.5%) showed LNM and 7 (31.8%) LVI. Follow-up was 32 ±8 months, with a 5-year overall survival of 42.9% for MCs and 76.6% for PDAs (p = 0.048). Univariate analysis found local recurrence (p = 0.001) and medullary subtype (p = 0.043) associated with lower survival.ConclusionsMedullary carcinomas were of greater tumor size and associated with more LVI and worse survival versus PDAs with MSI in stage III.

Colorectal carcinoma is one of the most common cancers in the human body. Colorectal carcinoma is a heterogeneous disease with variegated morphological patterns; some have shown themselves to have prognostic value. The World Health Organization classification recognizes many histological variants associated with adverse prognostic factors, one is the cribriform colonic carcinoma (CCC). In this work, we analyzed 18 cases of CCC compared with 228 conventional adenocarcinomas of colon, with the hypotheses that CCC compared with non-CCC have worse prognosis and decreased overall survival. CCC represent 7.3% of all colonic adenocarcinomas in this series, it presents in a median age of 56.3 years, all cases are in clinical stage III and IV, all invade subserosal adipose tissues or serosa, 90% have >5 positive lymph nodes and 89% have lymphovascular invasion. These known adverse prognostic factors reflect a lower 5-year survival, stage by stage, than conventional intestinal-type adenocarcinoma (56.8% vs 83.3%, P = .035). Cribriform carcinoma is a morphologic pattern that is underrecognized; in this work, we demonstrate its association with low survival, extensive lymphovascular invasion, and extensive lymph node metastasis, strong indicators of aggressive disease. Their proper recognition is mandatory to increase the number of cases and series to support our findings and include it in the current classifications.

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A critical review of recent international literature related to the use of intradialytic parenteral nutrition is given. The role of intradialytic parenteral nutrition as a therapy in malnourished hemodialysis patients is established and the need for systematic monitoring of this population at high risk of malnutrition is emphasized.

HighlightsThere are only two cases reported in the literature Merkel cell carcinoma in the retroperitoneum.The most plausible theory is the retroperitoneal mass could be a massively enlarged lymph node where precursor cells became neoplastic.The less probable theory is the non-described “regression” phenomena of a cutaneous MCC, but we are not found a primary skin lesion.Preoperative chemotherapy and excision of the primary tumor is the surgical treatment of choice for retroperitoneal MCC.