To evaluate the histopathological findings in appendectomy materials with E. vermicularis infection. Appendectomy materials with E. vermicularis infection of 24 cases were evaluated for the presence of acute inflammation, congestion, hemorrhage, perforation, lymphoid hyperplasia (LH), necrosis, granuloma, fecalith, obliteration, hyalinization, eosinophilic infiltration and mucosal architectural distortion. The frequency of E. vermicularis among 3222 appendectomies that were scanned for the study was 0.74% (24/3222). Female: male ratio was 1:1 and the median age was 12±9.34 years. The most common findings were LH (100%), and congestion (91.7%) Acute inflammation was found in one third (n=8), with phlegmonous inflammation and/or periappendicitis in 4 of them. The patients with periappendicitis were significantly younger (mean age 4 vs. 14.2 years, p=0.008). Feces was present in the lumen in 79.1% of the patients (fecalith in 25%, soft feces in 29.1% and feces mixed with blood and/or suppuration in 25%). In 6 cases (25%), only E. vermicularis was observed in the lumen, with acute appendicitis in 2 of them. Appendiceal lumen was completely obstructed in 12.5% (n=3), while it seemed narrow due to extensive LH in 3 (12.5%) cases. Fibrous obliteration was seen in 4 patients and it was correlated with age and eosinophil count in lamina propria p<0.05. While E. vermicularis infection appears to be an incidental finding in appendectomies rather than being a cause of appendicitis, it probably stimulates LH which may mimic acute appendicitis clinically.

Bone cysts are benign lesions occurring in any bone, regardless of age. They are often asymptomatic but may cause pain, swelling, fractures, and local recurrence and may be confused with other bone lesions. We retrospectively re-evaluated 143 patients diagnosed with aneurysmal bone cyst (n=98, 68.5%), solitary bone cysts (n=17 11.9%), pseudocyst (n=10.7%), intraosseous ganglion (n=3, 2.1%), hydatid cyst (n=2; 1.4), epidermoid cyst (n=1, 0.7%) and cysts demonstrating "mixed" aneurysmal-solitary bone cyst histology (n=12, 8.4%), and compared them with nonparametric tests. Aneurysmal bone cyst, solitary bone cysts and mixed cysts were frequently seen in the first two decades of life while the others occurred after the fourth decade. Aneurysmal bone cysts, intraosseous ganglion and pseudocysts were more common in women contrary to solitary bone cyst and mixed cysts (the female/male ratio was 1.22, 2 and 1.5 versus 0.7 and 0.5, respectively). Aneurysmal bone cyst, solitary bone cysts and "mixed" cysts were mostly seen in long bones, predominantly the femur, while epidermoid, hydatid and pseudocysts were all seen in flat bones like the vertebra, pelvis and mandible (p=0.001, chi-square). Repeat biopsies were performed in 19 cases (13.3%), 84.2% of which were aneurysmal bone cyst (5 conventional, 9 solid, 1 secondary and 1 subperiosteal) and three (15.8%) were mixed cysts (p=0.02, chi-square). Notably, some of them were located in inaccessible areas of pelvis (n=3), femur (n=3) and maxilla (n=2). The most common and challenging intraosseous cysts are aneurysmal bone cysts, particularly the "solid" variant. The "mixed" aneurysmal-solitary bone cyst "subgroup" requires further research with larger series to be defined more thoroughly.

Follicular cholecystitis (FC) is a poorly characterized entity. To determine its frequency/clinicopathologic associations. A total of 2550 cholecystectomy specimens were examined. Two hundred three of these were consecutive routine cholecystectomies submitted entirely for microscopic examination to determine the relative frequency of incidental pathologies in gallbladders (GBs). The remainder had representative sampling. Underlying conditions were nonobstructive pathologies (1270 nonspecific cholecystitis), obstructive (62 distal biliary tract tumors, 35 primary sclerosing cholangitis, and 31 autoimmune pancreatitis), and neoplastic (n = 949). FC was defined as 3 distinct lymphoid follicles (LFs)/centimeter. In the GBs totally submitted for microscopic examination, the true frequency of FC was found to be 2.5% (5/203), and in the representatively sampled group, it was 1.9%, with similar frequencies in nonobstructive, obstructive, and neoplastic cases (2.3%, 3.1%, and 1.3%, respectively, P = .77). When the 39 FC in nonneoplastic GBs contrasted with ordinary chronic cholecystitis, they were associated with older age (68 vs 49 years, P < .0001), similar gallstone frequency (68 vs 81%), female/male ratio (2.7 vs 2.6), and wall thickness (4 mm for both). None had lymphoma/parasites/Salmonella infection. Of 17 cases who had undergone gastric biopsy, 5 had chronic gastritis (2 with Helicobacter pylori). Microscopically, the LFs were the main inflammatory process often with minimal intervening inflammation. IgG4-positive plasma cell density was low (<10/high-power field) in 21/24(87.5%) cases. Follicular cholecystitis is seen in 2% of cholecystectomies, typically in significantly older patients, suggesting a deranged immune response. A third of the patients reveal biopsy-proven gastritis. FC does not seem to be associated with autoimmunity, lymphoma, or obstructive pathologies.

Gastrointestinal parasitosis is a significant cause of morbidity and mortality. Definitive diagnosis is usually made by stool tests and/or serology but may require tissue evaluation. Although pathologists are usually familiar with common parasites, it is not well established whether the diagnosis could be suspected without seeing the "parasite" itself. Resection or biopsy specimens of 32 cases with Giardia intestinalis (n=20), Enterobius vermicularis (n=5), Entamoeba histolytica (n=4), Fasciola hepatica (n=1), Strongyloides spp. (n=1) and Taenia saginata (n=1) infections were retrospectively re-evaluated for accompanying mucosal changes, and compared with nonparametric tests. The most common changes were congestion (65.6%) and eosinophilic infiltration (50%). Chronic active mucosal inflammation accompanied 37.5% of the cases. More than 10 eosinophils/HPF were present in 43.8%. Only one case of G. intestinalis, E. vermicularis, E. histolytica, and F. hepatica showed more than 50 eosinophils/HPF. Mucosal architectural abnormalities were present in 34.4%. Granulomas, giant cells and Charcot-Leyden crystals were only seen accompanying F. hepatica. No statistically significant difference was found between parasite subspecies regarding presence of inflammation, lymphoid aggregates, architectural distortion, congestion, ulceration and increase of eosinophils. Parasites induce nonspecific inflammation, slight mucosal architectural changes, mild eosinophilic infiltrate or granuloma formation. They may cause ulceration, bowel obstruction or perforation. Parasitosis should also be considered when evaluating cases mimicking inflammatory bowel disease, celiac disease or those that do not fulfill diagnostic criteria.

Background/Aims: The aim of the present study was to demonstrate the histopathological findings in gastrointestinal (GI) biopsies in adults with common variable immunodeficiency (CVID). Materials and Methods: A total of 172 GI biopsies of 26 patients with CVID obtained over a 16-year period were reevaluated. Findings were analyzed using descriptive analyzes and χ2 test. Results: Female-to-male ratio was 1.36. The median age at diagnosis was 36±13.94 (16-72) years. Chronic esophagitis was noted in 3 patients. The absence of plasma cells in the stomach, duodenum, and colon was observed in 16, 14, and 9 patients, respectively. Divergent results for the presence of plasma cells in concurrent stomach and duodenum samples were found in 11 (44%) patients. Nodular lymphoid hyperplasia (NLH) was notable in the duodenum (56%). The mean number of eosinophils in one high-power field was significantly higher in duodenal biopsies with NLH (27.21 vs. 14.37, p=0.002). Active inflammation was more prominent in the colon (91%) than in the stomach (65%) and duodenum (60%). Helicobacter pylori infection was found in 57.6%, including a case with persistent infection by the coccoid form. Celiac-like villous blunting and increased intraepithelial lymphocytes were seen in 40% and 24%, respectively. In addition, 23% had giardiasis associated with acute duodenitis and duodenal NLH (p<0.05). Conclusion: CVID gastroenteropathy is a challenging entity, and due to the heterogeneity in the presence and distribution of plasma cells throughout the GI tract and diverse disease course, multiple concurrent biopsies may be needed for tissue diagnosis. Duodenal CVID may present with villous alterations and giardiasis, and NLH appears to be an important clue in the duodenum. The association between duodenal NLH and eosinophil infiltration deserves further investigation.