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Background. Appendiceal well-differentiated neuroendocrine tumor is the most common histological type of appendiceal tumor. The majority of tumors are found incidentally at the tip of the appendix, with few exceptions. Due to its primarily indolent nature, this entity presents unique pathological challenges, particularly in the appropriate use of immunohistochemistry which this study aims to clarify. Patients and methods. Patients diagnosed at University Health Network (Canada) between 2005–2019 were selected and reviewed. Results. We identified 70 patients and sex distribution was female 60%; median age 36.5 years. Among them, 63 patients underwent appendectomy, and seven had initial right hemicolectomy for non-appendix lesions. Mean tumor size was 5.0 mm. Tumor extent was submucosa (15%); muscularis propria (34%); subserosa or mesoappendix (42%); visceral peritoneum (8%). All were clinically non-functional and negative for nodal and distant metastasis. Ninety percent of tumors were WHO Grade 1; 10% were WHO Grade 2. Immunohistochemically, an average of six stains were performed per patient. Nearly all tumors were positive for chromogranin A, synaptophysin, CAM5.2, and CDX2. MIB-1 staining was < 3% in 58/63 tumors. Other immunohistochemical stainings performed were hormonal markers (serotonin, glucagon, pancreatic peptide, peptide YY). Subsequent right hemicolectomy was performed on five patients. All were followed up (median 4 years 8 months), and all were alive without recurrence except for one patient who died of another comorbidity. Conclusion. Tumors that are small, localized, and of low grade can be reasonably exempt from an extensive immunohistochemical panel in the absence of non-typical clinical and morphological features. [ABSTRACT FROM AUTHOR]

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The hernia sac is a common surgical pathology specimen which can occasionally yield unexpected diagnoses. The College of American Pathologists recommends microscopic examination of abdominal hernias, but leaves submission of inguinal hernias for histology to the discretion of the pathologist. To validate this approach at a tertiary care centre, we retrospectively reviewed 1426 hernia sacs derived from inguinal, femoral and abdominal wall hernias. The majority of pathologies noted were known to the clinician, including herniated bowel, lipomas and omentum. A malignancy was noted in three of 800 inguinal hernias and seven of 576 abdominal wall hernias; five of these lesions were not seen on gross examination. Other interesting findings in hernia sacs included appendices, endometriosis, a perivascular epithelioid cell tumour, and pseudomyxoma peritoneii. All hernia sacs should be examined grossly as most pathologies are grossly visible. The decision to submit inguinal hernias for histology may be left to the discretion of the pathologist, but abdominal and femoral hernias should be submitted for histology. [ABSTRACT FROM AUTHOR]

The article presents a case study of a 25-year-old male with cystic fibrosis (CF) who developed acute abdominal pain with peritoneal signs.

OBJECTIVE. The purpose of this study was to determine whether a novel morphologic characteristic of appendiceal mucoceles at CT-focal distal appendiceal dilatation with a segment of morphologically normal appendix proximally-could predict an underlying neoplastic pathologic abnormality before surgery and histopathologic assessment. MATERIALS AND METHODS. A retrospective study was performed that assessed CT cases from 2012 through 2014. Cases showing morphologic features of a mucocele were identified and categorized into two subgroups: focal distal dilatation with a segment of normal appendix proximally and generalized appendiceal dilatation. The underlying histopathologic diagnosis for each case was assessed and categorized as neoplastic or nonneoplastic. Several additional morphologic findings were also assessed. RESULTS. Forty-nine cases with confirmed histopathologic diagnoses were identified. Of those, 20 of 23 (87.0%) cases with the finding of focal distal dilatation had an underlying neoplastic cause, whereas 14 of 26 (53.8%) cases with generalized dilatation had an underlying neoplastic cause ( p = 0.012). The findings of periappendiceal fat stranding ( p = 0.004), mural calcification ( p = 0.006), and degree of luminal dilatation ( p = 0.002) also reached statistical significance. When seen in combination with focal distal dilatation, the positive predictive value for underlying neoplasm approached or reached 100%. CONCLUSION. Our study shows that isolated focal distal appendiceal dilatation with a segment of morphologically normal appendix proximally is significantly associated with an underlying neoplastic histopathologic cause. When seen in combination with mural calcification, a diameter of more than 2 cm, and absence of periappendiceal stranding, an underlying neoplastic cause is strongly suggested.

Background: Many consider histology to be the gold standard for Helicobacter pylori detection. Because the number and distribution of H pylori organisms vary, particularly in patients taking proton pump inhibitors (PPIs), the American Gastroenterological Association recommends discontinuing PPIs two weeks before endoscopy, and taking biopsies from both the body and antrum., Objective: To assess the influence of clinical practice on the histopathological detection of H pylori infection., Methods: Electronic patient records were evaluated for the sites of gastric sampling and PPI use at endoscopy. One hundred fifty cases with biopsies taken from both antrum and body were randomly selected for pathological re-review with special stains. The gastric regions sampled, H pylori distribution and influence of clinical factors on pathological interpretation were assessed., Results: Between 2005 and 2010, 10,268 biopsies were taken to detect H pylori. Only one region was sampled in 60% of patients (antrum 47%, body 13%). Re-review of biopsies taken from both antrum and body indicated that the correct regions were sampled in only 85 (57%) patients. Of these, 54 were H pylori positive and 96 were H pylori negative. H pylori was present in the antrum in only 15% of the patients and body only in 21%. Of 96 H pylori-negative patients, two were reinterpreted as positive. Forty-seven per cent of patients were taking PPIs at endoscopy, contributing to both false-negative and false-positive diagnoses., Conclusion: Despite national and international guidelines for managing H pylori infection, the American Gastroenterological Association guidelines are infrequently adhered to, with PPIs frequently contributing to false diagnosis; sampling one region only increases the likelihood of missing active infection by at least 15%.

Perivascular epithelioid tumors (PEComa) are uncommon mesenchymal neoplasms demonstrating positivity for muscular and melanocytic immuno-markers. Included in this category are angiomyolipoma, lymphangioleiomyomatosis, and clear cell sugar tumors. Lesions which do not fit into these categories are classified as "not otherwise specified". We present a case of an incidentally discovered PEComa within inguinal hernia sac contents in a 70-year-old woman. It consisted of spindled and epithelioid cells with bland oval nuclei, small nucleoli and clear to light eosinophilic cytoplasm. There was no atypia or mitoses. The lesion was strongly positive for HMB45 and smooth muscle actin. Pelvic soft tissue and peritoneal PEComas are rarely reported in literature and very little is known about their prognosis. We discuss the immunohistochemistry, differential diagnosis, and pathogenesis of PEComas., (Copyright © 2013 Elsevier GmbH. All rights reserved.)