Interval appendicitis shows histological differences from acute appendicitis and may mimic Crohn disease and other forms of granulomatous appendicitis.

AIMS: While patients presenting with clinical signs and symptoms of acute appendicitis (AA) often receive surgical intervention shortly after presentation, certain patients may instead receive non-operative management initially, with appendectomy later. The histology of such interval appendicitis (IA) has only been described in small series. Also, we have noticed a recent increase in the incidence of IA specimens at our institution. METHODS AND RESULTS: We identified appendectomy specimens in our department during 2018 with available haematoxylin and eosin slides and electronic clinical data, and evaluated multiple histological findings. Cases were then divided into AA and IA, based on clinical history (AA if the patient presented to the hospital within 1 week of symptom onset and underwent appendectomy within 48 h; IA if appendectomy was delayed at least 1 week). Changes between groups were compared. The cohort included 165 cases (125 AA, 40 IA). Findings significantly more common in AA included mucosal acute inflammation, mural acute inflammation and acute serositis. Findings significantly more common in IA included Crohn-like mural inflammation, mural fibrosis, goblet cell hyperplasia, granulomas, xanthogranulomatous inflammation, haemosiderin-laden macrophages and granulation tissue. The rate of IA in 2018 (24%) was noticeably higher than in previous years. CONCLUSION: Acute inflammatory changes are more common in AA but can remain present in IA. Mural fibrosis, serosal adhesions, haemosiderin-laden macrophages and granulation tissue suggest IA. Granulomas and xanthogranulomatous inflammation can also be seen in IA, and Crohn-like mural inflammation is not uncommon. These histological patterns can guide signout and prevent diagnostic errors, particularly when clinical information is unavailable.

Primary Adrenal Epithelioid Angiosarcoma: A Case Report.

Primary adrenal angiosarcomas are exceedingly rare with a rapidly progressive clinical course and a poor outcome. Establishing the diagnosis can be challenging, and it is complicated by the fact that there are no characteristic clinical or imaging features that are pathognomonic for angiosarcoma. Histologically, they can overlap with other more commonly encountered adrenal tumors. Herein, we present an otherwise healthy 41-year-old woman diagnosed with a primary adrenal epithelioid angiosarcoma. We aim to expand the knowledge of the sparse literature existing on primary adrenal angiosarcomas to help better understand the diagnostic features, clinical behavior, and management of these rare tumors.

Comparative histologic features among liver biopsies with biliary-pattern injury and confirmed clinical diagnoses.

Biliary-pattern injury in the liver (eg, duct injury, ductular reaction, cholestasis) can occur in several conditions, including primary biliary cholangitis (PBC), primary sclerosing cholangitis (PSC), large duct obstruction (LDO), and drug-induced liver injury (DILI). While the histologic changes in these conditions have been individually well described, distinguishing among them remains often challenging, particularly when biopsy samples are limited in size, robust clinical information is unavailable, and/or the pathologist does not feel confident in evaluating liver disease. This study evaluated histologic features that could aid the diagnosis of biliary-pattern injury on biopsy. We reviewed 121 liver biopsies from clinically confirmed cases of PBC, PSC, chronic LDO, or DILI for multiple clinical and histologic parameters. The rates of these histologic findings were then compared among different entities. Onion-skin fibrosis was seen in 14% of PSC in comparison to 0%, 5%, and 0% of PBC, DILI, and chronic LDO (P = 0.031). Florid duct lesions were identified in 21% of PBC compared to 2% of PSC and 0% of DILI and LDO (P = 0.0065). Similarly, 42% of PBC showed lobular granulomas, compared to 7% of PSC, 11% of DILI, and 33% of chronic LDO (P = 0.0001). Cholestasis was more commonly seen in DILI (42%) and chronic LDO (83%) than in PBC (4%) and PSC (16%) (P < 0.0001). Lobular chronic inflammation was found in a significantly higher percentage of PBC and LDO than of PSC and DILI (P = 0.0009). There were significantly fewer cases of PBC showing neutrophils in ductular reaction than PSC, DILI, and LDO (P = 0.0063). Histologic findings that can help suggest a diagnosis in liver biopsies with biliary-pattern injury include florid duct lesions, lobular granulomas, lack of neutrophils in ductular reaction, and lobular chronic inflammation in PBC; onion-skin fibrosis in PSC; cholestasis and feathery degeneration in DILI; and lobular granulomas, lobular chronic inflammation, cholestasis, and feathery degeneration in chronic LDO. These findings are likely most helpful when complicating factors interfere with biopsy interpretation.

Erroneous Patient Tissue Contaminants in 1574 Surgical Pathology Slides: Impact on Diagnostic Error and a Novel Framework for Floater Management.

CONTEXT.­: Tissue contaminants on histology slides represent a serious risk of diagnostic error. Despite their pervasive presence, published peer-reviewed criteria defining contaminants are lacking. The absence of a standardized diagnostic workup algorithm for contaminants contributes to variation in management, including investigation and reporting by pathologists. OBJECTIVE.­: To study the frequency and type of tissue contaminants on microscopic slides using standardized criteria. Using these data, we propose a taxonomy and algorithm for pathologists on "floater" management, including identification, workup, and reporting, with an eye on patient safety. DESIGN.­: A retrospective study arm of 1574 histologic glass slides as well as a prospective study arm of 50 slide contamination events was performed. Using these data we propose a structured classification taxonomy and guidelines for the workup and resolution of tissue contamination events. RESULTS.­: In the retrospective arm of the study, we identified reasonably sized benign tissue contaminants on 52 of 1574 slides (3.3%). We found size to be an important parameter for evaluation, among other visual features including location on the slide, folding, ink, and tissue of origin. The prospective arm of the study suggested that overall, pathologists tend to use similar features when determining management of potentially actionable contaminants. We also report successfully used case-based ancillary testing strategies, including fluorescence in situ hybridization analysis of chromosomes and DNA fingerprinting. CONCLUSIONS.­: Tissue contamination events are underreported and represent a patient safety risk. Use of a reproducible classification taxonomy and a standardized algorithm for contaminant workup, management, and reporting may aid pathologists in understanding and reducing risk.