Defined morphological criteria allow reliable diagnosis of colorectal serrated polyps and predict polyp genetics

Criteria for the diagnosis of serrated colorectal lesions (hyperplastic polyp, sessile serrated adenoma without or with dysplasia—which we called mixed polyp—and traditional serrated adenoma) for which consensus has been reached should be validated for applicability in daily practice in terms of inter-observer reproducibility and their association with clinical features and (epi)genetic events. A study set was created from a consecutive series of colorectal polyps (n?=?1,926) by selecting all sessile serrated adenomas, traditional serrated adenomas and mixed polyps. We added consecutive series of hyperplastic polyps, classical adenomas and normal mucosa samples for a total of 200 specimens. With this series, we conducted an inter-observer study, encompassing ten pathologists with gastrointestinal pathology experience from five European countries, in three rounds in which all cases were microscopically evaluated. An assessment of single morphological criteria was included, and these were correlated with clinical parameters and the mutation status of KRAS, BRAF and PIK3CA and the methylation status of MLH1. Gender, age and localisation were significantly associated with certain types of lesions. Kappa statistics revealed moderate to good inter-observer agreement for polyp classification (κ = 0.56 to 0.63), but for single criteria, this varied considerably (κ = 0.06 to 0.82). BRAF mutations were frequently found in hyperplastic polyps (86 %, 62/72) and sessile serrated adenomas (80 %, 41/51). KRAS mutations occurred more frequently in traditional serrated adenomas (78 %, 7/9) and less so in classical adenomas (20 %, 10/51). Single morphological criteria for sessile serrated adenomas showed significant correlation with BRAF mutation (all p?≤?0.001), and those for classical adenomas or traditional serrated adenoma correlated significantly with KRAS mutation (all p?<?0.001). Therefore, single well-defined morphological criteria are predictive for genetic alterations in colorectal polyps.     

Risk assessment and pathological reporting of gastrointestinal stromal tumour

Gastrointestinal stromal tumour (GIST) is the most common mesenchymal neoplasm of the GI tract. GISTs form a biological continuum ranging from benign incidentally detected minute lesions (stromal tumourlets) of no clinical significance to large and highly malignant sarcomatous neoplasms. The disease is characterized by indistinct borders between biologically different subsets within its spectrum leading to unpredictable course of the disease in the majority of cases. Availability of effective tyrosine kinase inhibitors underlined the urgent need for a reliable risk assessment system to reliably identify those patients who are at a significant risk for disease relapse and would thus profit from currently available effective targeted molecular therapy. While several risk systems have been established for GIST over the last decade, evidence is growing that no single system is optimal for all patients. Accordingly, an individualized risk system integrating classical parameters (site, size, mitotic index), status of serosal mechanical barrier covering the tumour (presence of tumour rupture or serosal penetration) as well as several other still debatable histological (coagulative necrosis, venous invasion, mucosal infiltration), biomarkers (proliferative index, p16 expression, etc.), and molecular (specific mutation types, adverse chromosomal aberrations, etc.) prognosticators would be of superb value for selecting the most appropriate patient treatment.     

Deep-seated huge hibernoma of soft tissue: a rare differential diagnosis of atypical lipomatous tumor/well differentiated liposarcoma

Background: Hibernoma is a rare benign fat-forming soft tissue tumor that differentiates similar to brown fat, hence an origin from remnants of fetal brown adipose tissue has been proposed. Mainly young adults are affected, usually without significant clinical symptoms. Material and methods: We report on four patients with hibernomas, who were treated at our hospital during the last 10 years. The clinicopathologic and immunohistochemical features are presented and treatment and follow-up data discussed. Results: Patients were 2 women and 2 men aged 21-67 years (mean: 45 yrs) who presented with a slowly growing, painless mass. The anatomic location was the thigh, upper arm, lateral thoracic wall and paravertebral soft tissue. Two of them were diagnosed preoperatively through a percutaneous core needle biopsy and the other two underwent surgery because of high clinical and radiological suspicion of liposarcoma. The tumor’s size ranged from 7 cm to 15.5 cm (mean: 11 cm). All were deep-seated subfascial intramuscular masses. Histologically, all four tumors were of the typical variant. All patients underwent a R0-surgical resection of the tumor and they were recurrence-free at last follow-up (mean: 47 months; range: 25-87). Conclusion: Hibernoma may present as huge deep intramuscular soft tissue mass in adults, closely mimicking well differentiated liposarcoma and should be considered in the differential diagnosis of fatty soft tissue tumors in any location. Surgical excision is the treatment of choice. The tumor has no malignant or recurrence potential.     

Histopathological changes of gastric mucosa following oral administration of fumonisin B1 in mice

Fumonisin B1 is a common secondary metabolite produced by Fusarium moniliforme that occurs in corn and corn-based foods. This mycotoxin is toxic to many species of laboratory and domestic animals and is known to induce a variety of diseases such as hepatic cancer and renal and hepatic dysfunction. The structure of fumonisin B1 (FB1) resembles sphingolipids so it can inhibit synthesis of ceramide, an enzyme in the sphingolipid biosynthetic pathway. This inhibition leads to the disruption of sphingolipid metabolism and increased levels of sphinganine and sphingosine (sphingoid bases) in the serum of treated animals. It is believed that the toxicity effect of fumonisin B1 is the result of these sphingoid bases. In the present research, mice were treated with FB1 to determine its pathological effects on gastric gland and gastric mucosa in the treated mice. For this purpose, the mice were randomly assigned into two groups, namely, control (n?=?14) and treatment (n?=?15). The treatment group was fed with prepared food containing FB1 (150 mg/kg) for a period of 4 months. One day after the last treatment, all animals in both groups were euthanized and their stomach were sampled and prepared for microscopic analysis. Histopathological analysis revealed a significant decrease in parietal cell number and a significant increase in the number of inflammatory cells in gastric mucosa. Also, atrophy of gastric glands was observed. The study confirmed that FB1 poisoning can have toxicopathological effects such as gastric gland atrophy and gastritis on mice gastric tissue.     

Narasin poisoning in the dromedary camel (Camelus dromedarius)

Narasin poisoning was reported in 15 camels, 7 adults and 8 young, after accidental access to poultry feed medicated with 60 g narasin per ton. Fourteen camels died between 3 and 20 days, and one young animal survived the dose after developing a chronic course of a disease. The main clinical signs of narasin toxicity in the dromedary include: weakness of hind limbs, lack of coordination, oedema of dependent parts, inappetence, ruminal atony, myoglobinuria, profound depression, tachycardia, sternal recumbency and death. The lesions were mainly in the heart and skeletal muscles and consisted of multifocal degeneration and necrosis of heart and skeletal muscle fibres with areas of regeneration and lung oedema. There was high enzyme activity for creatine kinase (CK), lactate dehydrogenase, aspartate aminotransferase and alanine aminotransferase and an increase in urea concentration and white blood cells, neutrophil and platelet counts. Cardiac markers, troponin T, CK-MB and C-reactive protein, showed slight or no changes terminally.