Mannan, Abul A S R

AimsWe compiled two cohorts of colorectal adenosquamous carcinoma (ASC) to describe its histologic and molecular aspects using modern parameters to compare them with literature reports using meta‐analysis of cohorts and individual case series.Methods and ResultsWe identified 53 colorectal ASC from 19 North American academic medical centres, in addition to national database reports on 94 Dutch cases. We analysed available clinical, histologic, and immunohistochemical features and patient outcome. ASC comprised 0.02% of colorectal cancers in the Dutch database. The median cohort patient ages at resection were 65 and 69 years (North American and Dutch cohorts, respectively), with a roughly equal male:female ratio. The squamous component represented between 5% and 95% of each tumour, with a median of 50%. Tumour‐infiltrating lymphocytes (TILs) were generally low (66%), and tumour budding was often Bd1 (64%). Most cases were pT3 (55%) or pT4 (40%), with nodal metastases in more than half (58%). Twenty‐three cases (43%) metastasized distantly, most commonly to the liver. Mismatch repair (MMR) deficiency was identified in 34% of the cases. Follow‐up was available for 48 patients; 13 (27%) had recurrent disease and 29 (60%) died. A total of 31 patients progressed, with median time to progression of 18 months. Available data for the Dutch cohort revealed largely similar findings, as did review of cases in the literature.ConclusionColorectal ASC usually presents at an advanced stage. Despite high rates of MMR deficiency and low tumour budding, TILs were generally low, and there is a high recurrence rate and poor prognosis.

AimsGastric heterotopia (GH) has been described throughout the gastrointestinal tract. However, the colorectal region is an extremely rare location for it. We describe the clinicopathological features of GH of the colon, rectum and anus.Methods and resultsWe identified 33 cases in 20 males and 13 females (median age = 54 years; range = 4 months–73 years). Sites included the rectum (n = 26), anus (n = 4), ileocaecal junction (n = 1), ascending colon (n = 1) and descending colon (n = 1). Presenting symptoms (n = 27) included haematochezia (41%) and altered bowel habits (4%); 15 patients (55%) were asymptomatic. On colonoscopy (n = 31), all appeared as solitary lesions (median size = 6.5 mm, range = 2–55 mm), either as polyps (61%), raised erythematous patches (23%), an ulcer (10%), within a rectal diverticulum (3%) or a haemorrhoid (3%). Patients were managed by polypectomy. One with an associated carcinoma in the area of GH underwent resection. No morbidity related to GH itself was reported following excision. Histologically, heterotopic gastric mucosa was oxyntic (85%), mixed oxyntic and non‐oxyntic (12%) and not specified (3%) types. In five patients a pyloric gland adenoma (PGA) arose from heterotopic gastric mucosa, two of which contained a focus of invasive adenocarcinoma. One case had associated surface foveolar‐type low‐grade dysplasia. Another had associated adenocarcinoma arising from the heterotopic mucosa. One example harboured Helicobacter pylori organisms.ConclusionsWe highlight the features of GH in the distal GIT – the ‘outlet patch’. Association with PGA, surface dysplasia and adenocarcinoma suggests that lower tract GH can undergo neoplastic transformation.