An ALK Immunohistochemical Pitfall: -Positive Histiocytosis Versus Angiomatoid Fibrous Histiocytoma.

The proliferation of recognized neoplasms related to related to rearrangements involving kinase genes, arising in diverse somatic tissue lineages, poses an increasing challenge in surgical pathology. For instance, ALK rearrangements have been observed in diverse neoplasms of epithelial, connective tissue, and hematolymphoid lineages, many of which are associated with overexpression of ALK by immunohistochemistry as a useful biomarker. An even higher order challenge and pitfall would be the scenario where a tumor an ALK rearrangement nonetheless overexpresses the protein, thereby simulating an ALK-defined neoplasm.

Urothelial carcinoma in situ with "early papillary formation" vs "lateral spread/shoulder lesion" of prior high-grade noninvasive papillary urothelial carcinoma: A survey of pathologist and urologist interpretations.

Objectives: Urothelial carcinoma in situ (CIS) with early papillary formation is terminology sometimes used to suggest incipient high-grade papillary urothelial carcinoma (PUC) but may lead to confusion between true CIS and lateral flat spread of PUC.

Methods: It remains unclear how pathologists and urologists interpret this scenario, so a survey was circulated to 68 pathologists (group 1 = 28 academic genitourinary pathologists; group 2 = 17 pathologists with a self-reported genitourinary focus; group 3 = 23 pathologists self-reported as not genitourinary specialists) and 32 urologists.

Results: Regarding atypical urothelial lesions that appear mainly flat but contain possible papillae, group 3 was more likely to label this as CIS compared with groups 1 and 2 (35% for group 3 vs 13% for groups 1 and 2), while groups 1 and 2 more often adopted another descriptive diagnosis, such as "CIS with early papillary features" (38% for groups 1 and 2 vs 13% for group 3).

Intraductal Carcinoma of the Prostate versus Simulants: A Differential Diagnosis Growing in Clinical Impact.

Despite its first recognition even longer ago, in the past nearly 20 years, intraductal carcinoma of the prostate has become a standard histopathologic reporting parameter conveying a strong negative prognostic factor for prostatic adenocarcinoma. When seen at biopsy, intraductal carcinoma of the prostate is associated with risk for aggressive prostatectomy outcomes, including frequently high-grade, high-stage, high-volume disease, with increased risk for recurrence and progression. Multiple organizations, including the uropathology subspecialty societies to the World Health Organization, recognize and recommend reporting the presence of intraductal carcinoma, whether sampled in "pure" form or present with concomitant invasive adenocarcinoma.

Contemporary Diagnostic Reporting for Prostatic Adenocarcinoma: Morphologic Aspects, Molecular Correlates, and Management Perspectives.

The diagnosis and reporting of prostatic adenocarcinoma have evolved from the classic framework promulgated by Dr Donald Gleason in the 1960s into a complex and nuanced system of grading and reporting that nonetheless retains the essence of his remarkable observations. The criteria for the "Gleason patterns" originally proposed have been continually refined by consensuses in the field, and Gleason scores have been stratified into a patient-friendly set of prognostically validated and widely adopted Grade Groups. One product of this successful grading approach has been the opportunity for pathologists to report diagnoses that signal carefully personalized management, placing the surgical pathologist's interpretation at the center of patient care.

The New WHO Category of "Molecularly Defined Renal Carcinomas": Clinical and Diagnostic Features and Management Implications.

The evolution of classification of renal tumors has been impacted since the turn of the millennium by rapid progress in histopathology, immunohistochemistry, and molecular genetics. Together, these features have enabled firm recognition of specific, classic types of renal cell carcinomas, such as clear cell renal cell carcinoma, that in current practice trigger histologic-type specific management and treatment protocols. Now, the fifth Edition World Health Classification's new category of "Molecularly defined renal carcinomas" changes the paradigm, defining a total of seven entities based specifically on their fundamental molecular underpinnings.

Unexpected Clinical Outcome for Myxoinflammatory Fibroblastic Sarcoma, When Should They Be Considered High Grade?

Myxoinflammatory fibroblastic sarcoma (MIFS) is a rare tumor of soft tissue. It typically presents as a low-grade sarcoma with myxoid stroma, has a predilection for distal extremities, and displays a high propensity for local recurrence, but low metastatic potential. The risk factors associated with high-risk lesions metastasizing are poorly defined.

Application of ChatGPT in Routine Diagnostic Pathology: Promises, Pitfalls, and Potential Future Directions.

Large Language Models are forms of artificial intelligence that use deep learning algorithms to decipher large amounts of text and exhibit strong capabilities like question answering and translation. Recently, an influx of Large Language Models has emerged in the medical and academic discussion, given their potential widespread application to improve patient care and provider workflow. One application that has gained notable recognition in the literature is ChatGPT, which is a natural language processing "chatbot" technology developed by the artificial intelligence development software company OpenAI.

A -Amplified Renal Cell Carcinoma with Long-Term, Complete Immunotherapy Response: Retrospective Support for the Value of Molecular Classification.

Recent years have seen the recognition and establishment of numerous subtypes of renal cell carcinoma (RCC), including adoption of an entire category of "molecularly defined renal carcinomas" in the fifth Edition of World Health Organization Classification. To add value, new diagnostic entities should be clinicopathologically distinct, or better, imply specific management and treatment angles, especially if adjunctive testing is needed for diagnosis. One such promising future treatment angle for a molecularly defined subtype, -amplified RCC, is immunotherapy, for which recent scholarship has demonstrated frequent expression of PD-L1.

Renal Neoplasia Occurring in Patients With PTEN Hamartoma Tumor Syndrome : Clinicopathologic Study of 12 Renal Cell Carcinomas From 9 Patients and Association With Intrarenal "Lipomas".

The aim of this study was to assess the histopathologic spectrum of renal tumors in patients with PTEN hamartoma tumor syndrome (PHTS), with a specific focus on potential features predictive of the underlying syndrome. A multi-institutional study was conducted to obtain clinical and pathologic data on renal tumors arising in patients with PHTS, either diagnosed by germline mutational analysis or clinical criteria for Cowden syndrome. Histologic sections of the renal tumors were re-reviewed for classification.

Uncoupled nitric oxide synthase activity promotes colorectal cancer progression.

Increased levels of reactive oxygen/nitrogen species are one hallmark of chronic inflammation contributing to the activation of pro-inflammatory/proliferative pathways. In the cancers analyzed, the tetrahydrobiopterin:dihydrobiopterin ratio is lower than that of the corresponding normal tissue, leading to an uncoupled nitric oxide synthase activity and increased generation of reactive oxygen/nitrogen species. Previously, we demonstrated that prophylactic treatment with sepiapterin, a salvage pathway precursor of tetrahydrobiopterin, prevents dextran sodium sulfate-induced colitis in mice and associated azoxymethane-induced colorectal cancer.

POU2AF3-rearranged sarcomas: A novel tumor defined by fusions of EWSR1 or FUS to a gene formerly designated COLCA2.

Gene fusions involving EWSR1 or FUS as the 5' partner have been reported in a diverse array of sarcomas. Here, we characterize the histopathology and genomics of six tumors harboring a gene fusion between EWSR1 or FUS and POU2AF3, an understudied, putative colorectal cancer predisposition gene. Striking morphologic features reminiscent of synovial sarcoma were observed including a biphasic appearance with variable fusiform to epithelioid cytomorphology and staghorn-type vasculature.

Myoepithelial carcinoma of the bladder: Case report and review of the literature.

Myoepithelial carcinoma is a neoplasm that classically arises in the parotid glands, nasopharynx, paranasal sinus, and nasal cavity of the head and neck. It rarely arises in other organs or soft tissues and involvement of genitourinary organs is distinctly rare. We describe a case of a 21-year-old male, presenting with nausea, weight loss, and worsening suprapubic pain over 3 months, found to have a large mass at the dome of the bladder.

Antagonism between Prdm16 and Smad4 specifies the trajectory and progression of pancreatic cancer.

The transcription factor Prdm16 functions as a potent suppressor of transforming growth factor-beta (TGF-β) signaling, whose inactivation is deemed essential to the progression of pancreatic ductal adenocarcinoma (PDAC). Using the KrasG12D-based mouse model of human PDAC, we surprisingly found that ablating Prdm16 did not block but instead accelerated PDAC formation and progression, suggesting that Prdm16 might function as a tumor suppressor in this malignancy. Subsequent genetic experiments showed that ablating Prdm16 along with Smad4 resulted in a shift from a well-differentiated and confined neoplasm to a highly aggressive and metastatic disease, which was associated with a striking deviation in the trajectory of the premalignant lesions.

Clear cell renal cell carcinoma with focal psammomatous calcifications: a rare occurrence mimicking translocation carcinoma.

Aims: Renal cell carcinoma (RCC) with clear cells and psammoma-like calcifications would often raise suspicion for MITF family translocation RCC. However, we have rarely encountered tumours consistent with clear cell RCC that contain focal psammomatous calcifications.

Methods And Results: We identified clear cell RCCs with psammomatous calcifications from multiple institutions and performed immunohistochemistry and fluorescence and RNA in-situ hybridisation (FISH and RNA ISH).

Influence of intermolecular interactions on the infrared complex indices of refraction for binary liquid mixtures.

This paper investigates the accuracy of deriving the composite optical constants of binary mixtures from only the complex indices of refraction of the neat materials. These optical constants enable the reflectance spectra of the binary mixtures to be modeled for multiple scenarios (, different substrates, thicknesses, volume ratios), which is important for contact and standoff chemical detection. Using volume fractions, each mixture's complex index of refraction was approximated three different mixing rules.

Immunohistochemical expression of renin and GATA3 help distinguish juxtaglomerular cell tumors from renal glomus tumors.

Juxtaglomerular cell tumors and glomus tumors both arise from perivascular mesenchymal cells. Juxtaglomerular cells are specialized renin-secreting myoendocrine cells in the afferent arterioles adjacent to glomeruli, and juxtaglomerular tumors derived from these cells are therefore unique to the kidney. In contrast, glomus tumors have been described at numerous anatomic sites and may show significant morphologic and immunophenotypic overlap with juxtaglomerular tumors when occurring in the kidney.

Too Sensitive or Just Right?

Objectives: To compare the performance of the rabbit monoclonal antihuman CD246 antibody (D5F3 clone) with the established ALK1 clone for immunohistochemical assessment of anaplastic large cell lymphoma (ALCL).

Methods: Archival cases of ALCL (n = 27) were assessed immunohistochemically by use of ALK1 and D5F3 clones under standard Clinical Laboratory Improvement Amendments-compliant conditions. The intensity of cytoplasmic staining (0 = none; 1 = faint; 2 = moderate; 3+ = strong) and proportion of neoplastic cells (0%, <5%, 5%-50%, >50%) were evaluated and compared with clinical ALK break-apart fluorescence in situ hybridization (FISH) assays.

Flat intraurothelial lesions of the urinary bladder-do hyperplasia, dysplasia, and atypia of unknown significance need to exist as diagnostic entities? and how to handle in routine clinical practice.

Classification of the putative flat preneoplastic and neoplastic lesions of the urothelium with features subthreshold for urothelial carcinoma in situ remains a challenging, indeed, vexing problem in diagnostic surgical pathology. This area, subtending lesions including flat urothelial hyperplasia, urothelial dysplasia, and atypia of unknown significance, has struggled under evolving classifications, changing criteria, and limited clinical actionability, all confounded by the recognized lack of diagnostic reproducibility. Herein, we review the state of the literature around these lesions, reviewing contemporary criteria and definitions, assessing the arguments in favor and against of retaining hyperplasia, dysplasia, and atypia of unknown significance as diagnostic entities.