Morphologic Spectrum Research Articles

Hybrid Epithelioid Schwannoma/Neurofibroma: A Report of 3 Cases.

Peripheral nerve sheath tumors can include neurofibroma, schwannoma, and perineurioma, with hybrid nerve sheath tumor (HNST) being rare. We describe 3 HNST cases with epithelioid schwannoma and neurofibroma features, an uncommon manifestation of hybrid schwannoma/neurofibroma. The 3 cases involved the upper back, forearm, and thigh. Histopathologically, the tumors were located in the subcutis or dermis and subcutis. The epithelioid schwannoma component showed nests/cords of epithelioid cells with round nuclei and abundant cytoplasm. In contrast, the neurofibroma component showed spindle cell proliferation within myxoid stroma. The 3 cases showed variable proportions of both components. Immunohistochemically, the epithelioid schwannoma components were positive for S100 protein and negative for CD34, whereas the neurofibroma component showed partial S100 immunoreactivity and contained abundant CD34-positive cells with a fingerprint pattern. Epithelial membrane antigen and GLUT1 revealed the perineurial capsules. In conclusion, our cases expand the morphologic spectrum of HNST and underscore the importance of recognizing this variant.

Phenotype of vegetations: a retrospective echocardiographic analysis of patients with native valve endocarditis.

Abstract Background Echocardiography plays a central role in the diagnosis of infective endocarditis. Vegetations may present in various phenotypes depending on the bacterium involved and the immune state of the patient. Differentiation from thrombus and particularly non-bacterial thrombotic endocarditis (NBTE) in cancer patients can prove challenging. We sought to perform a retrospective morphologic echocardiographic analysis of vegetations and evaluate its association with the clinical and microbiological data in patients with native valve endocarditis. Methods We retrospectively included all patients from our tertiary referral center who were diagnosed with native valve endocarditis from 01/2019 until 12/2022. Baseline echocardiography was reviewed by two observers, vegetations were classified regarding their morphology. Clinical data was documented from chart analysis. Results A total of n=60 patients were included in this preliminary analysis, 44/60 (73,3%) were male, mean age was 68,2 years (±12,4). Blood cultures were positive in 55/60 (91.7%), the most common microorganisms identified being Staphylococcus aureus in 36.7%, viridans streptococci in 21.7%, enterococci in 20%, and other staphylococci species in 10%. Valves affected were mitral valve in 38.3%, aortic valve in 36.7%, tricuspid valve in 13.3%, and more than one valve in 10%. Cardioembolic events occurred in 24/60 (40%), most commonly cerebral stroke 18/24 (75%), splenic 4/24 (16.6%) and renal infarction 3/24 (12.5%). Charlson comorbidity index was 6.33 (±2.8). A total of 31/60 (51.6%) patients were operated. In-hospital mortality was 28.3%. A total of 14/60 (23%) patients had active malignant disease at the time of diagnosis of endocarditis. Eleven (18.3%) were additionally immunocompromised due to chemotherapy. Median vegetation size area was 0.79 cm² (0,47; 1,26), mean length was 12.4mm. It was classified as raceme in 20 (33%), filiform in 16 (27%), broad-based in 16 (27%), and broad-based with filiform foothills in eight (13%) patients (figure 1). There was no statistically significant association of morphology with outcome or the underlying microorganism (table 1). Discussion: Endocarditis is a detrimental disease with high rates of morbidity and mortality, which was once again documented in this cohort. A quarter of the patients had active malignant disease. With port infection as common entry for bacteremia, and immunosuppression due to cancer itself and due to chemotherapy as predisposition, this group is particularly vulnerable. While NBTE must be on the list of differential diagnoses, probability for infective endocarditis is high if vegetations are present. In this retrospective analysis, we could show a diverse spectrum of echocardiographic morphology of vegetations ranging from broad-based to raceme configuration with no statistical association with underlying microorganism or outcome. Table 1 Figure 1

SMARCB1-deficient Sinonasal Carcinoma

SMARCB1-deficient sinonasal carcinoma (SDSC) is a recently recognized rare malignancy. Despite growing awareness, SDSC remains susceptible to misdiagnosis owing to its rarity and overlapping features with diverse mimics. A retrospective review of the clinical and pathologic features of 32 SDSC including 4 SMARCB-1 deficient adenocarcinoma (SDAC) cases was performed. The patients were aged 19 to 76 years with a male predominance. Most tumors arose in the naso-ethmoid (75%), and advanced stage (93.6%), with frequent multi-sinus (90.5%) involvement. Histologically, tumors exhibited diverse morphologies, including basaloid (50%), rhabdoid (25%), and undifferentiated (12.5%) types. SDAC cases showed glandular differentiation with intraluminal and stromal mucin. Empty vacuoles (62.5%), pagetoid spread (31.3%), eosinophilic-granular bodies (18.8%), hyaline globules (15.2%), and florid glomeruloid neovascularization (15.6%) were additional findings. Yolk sac-like areas were encountered in 18.6%. Immunohistochemically, tumors were defined by a complete loss of SMARCB1 (100%); a variable reactivity for p40 (65.6%), synaptophysin (13.6%), glypican3 (6.1%), and CD34 (6.1%) was present. Notably, >90% of our patients had different initial diagnoses before referral. Lymph node metastasis, locoregional recurrence, and distant metastasis were seen in 23.3%, 24.1%, and 27.6% patients, respectively; 37.9% died of disease. In conclusion, SDSCs are rare and aggressive sinonasal malignancies that display a wide histologic spectrum including glandular differentiation. This study expands on the morphologic spectrum of SDSC by analyzing a large cohort of 32 cases, adding comprehensive clinical, histopathologic, and immunohistochemical data, and highlighting features to improve diagnostic accuracy. The emergence of targeted therapies, such as EZH2 inhibitors, further underscores the importance of accurate diagnosis.

Alternative driver pathways in peripheral nerve sheath tumors - including DICER1 and/or KRAS alterations.

DICER1-associated sarcoma is an emerging entity, defined by either somatic or germline dicer 1, ribonuclease III (DICER1) mutations and sharing characteristic morphologic features irrespective of the site of origin. In addition to the DICER1 driver mutation, concurrent genomic alterations, including tumor protein 53 (TP53) inactivation and RAS pathway activation, are frequently detected. Tumors that morphologically resemble malignant peripheral nerve sheath tumor (MPNST) have rarely been reported among DICER1 sarcomas and often pose diagnostic challenges. This study was prompted by a case involving morphologic features of MPNST, which harbored co-existing DICER1 and hotspot KRAS mutations. Hence, we investigated the incidence of these alterations in PNST from our molecular database compared to the genomic and morphologic spectrum of DICER1-mutant sarcomas. In total, we identified three cases diagnosed as MPNST with co-existing DICER1, ATRX chromatin remodeler (ATRX), and KRAS G12V/A alterations occurring in brain, cerebellopontine angle, and intra-abdominal sites. Two additional cases each of MPNSTs and neurofibromas were identified with hotspot KRAS mutations. All five MPNSTs lacked canonical neurofibromin 1 (NF1)/neurofibromin 2 (NF2) alterations, displaying a classic morphologic appearance with fascicular monomorphic spindle cells and followed a diverse clinical behavior. Among the 38 DICER1-associated sarcomas in our database, eight (21%) had secondary KRAS hotspot mutations, all composed of monomorphic spindle and/or round cells, including three with an MPNST-like histology. In contrast, all 10 (26%) DICER1-mutant sarcomas with TP53 mutations showed a pleomorphic phenotype. The DNA-based methylation profile of our index case clustered within the group of sarcomas with DICER1 alterations. Our results highlight a small subset of MPNST associated with DICER1 and/or KRAS mutations. However, their relationship with conventional MPNST remains to be determined in larger studies. © 2025 The Pathological Society of Great Britain and Ireland.

Cholangioblastic Cholangiocarcinoma (NIPBL::NACC1 cholangiocarcinoma): Expanded Morphologic Spectrum and Further Genetic Characterization.

The cholangioblastic variant of intrahepatic cholangiocarcinoma is a distinctive neoplasm that typically affects young women without underlying liver disease. Morphologically, it demonstrates solid, trabecular, and tubulocystic architecture, biphasic small cell-large cell cytology, and immunoreactivity for inhibin, neuroendocrine markers, and biliary but not hepatocellular markers. In 2021, our group identified a characteristic NIPBL::NACC1 gene fusion in cholangioblastic cholangiocarcinoma, and since then ~20 genetically confirmed cases have been reported in the literature. We report 2 additional cases, both of which caused diagnostic challenges. The first was previously published as a "biliary adenofibroma with malignant features" which we now show recurred as a high-grade adenocarcinoma. Re-review of the original lesion demonstrated the morphologic and immunohistochemical features of highly cystic cholangioblastic cholangiocarcinoma, whereas the high-grade recurrence lacked many of these features. In addition to the characteristic NIPBL::NACC1 gene fusion, the recurrence demonstrated loss of the RB1 and PTEN genes which were found in the highly cystic, bland areas of the original tumor, suggesting that the recurrence was derived from this bland component. The second case was originally misclassified as metastatic well-differentiated neuroendocrine neoplasm and only focally demonstrated the characteristic biphasic small cell-large cell cytology. In addition, a review of 7 cholangioblastic cholangiocarcinomas in our files demonstrates that loss of chromosome 13q14.2 (where the RB1 gene resides) and loss of chromosome 6q15-q16.3 are recurrent secondary changes in these neoplasms. Expression profiling demonstrated alterations in the transforming growth factor receptor beta superfamily, and overexpression of MYC which was validated by immunohistochemistry. Our findings expand the morphologic and genetic spectrum of this neoplasm and provide insight into secondary genetic changes associated with progression.

An investigation of the use of Google Street View for identifying gentrification across diverse United States morphological city types

ABSTRACT Google Street View (GSV) is a tool for measuring characteristics of the built environment and appropriate for analyzing change in neighborhoods longitudinally. We investigate whether using GSV to identify gentrification works across the spectrum of urban morphologies in the U.S. We first use Hirsch and Schinasi’s (2019, A measure of gentrification for use in longitudinal public health studies based in the United States. Drexel University Urban Health Collaborative.) gentrification criteria to identify tracts that underwent gentrification between 2012 and 2019 in Boston, Cincinnati, and Phoenix. We then used Hwang’s (2015, Gentrification, race, and immigration in the changing American city [Unpublished doctoral dissertation] Harvard University.) GSV-based gentrification index, originally used in Chicago, to measure gentrification in the built environment and look for alignment with gentrification using Hirsch & Schinasi’s criteria. Alignment was best in Boston with a population density and built form closest to Chicago’s. The process did not work as well for Cincinnati where gentrification was concentrated in only a few blocks within gentrifying tracts nor in Phoenix with its limited amount of up-scale high-density apartments/condominiums and numerous vacant parcels. We conclude that cities with different urban morphologies need different methods to detect evidence of gentrification in the built environment.

STK11 Adnexal Tumor: Exploring the Association With Peutz-Jeghers Syndrome and its Distinction From Morphologic Mimickers.

STK11 adnexal tumor is a novel malignant neoplasm of uncertain histogenesis frequently arising in a para-adnexal location and associated with Peutz-Jeghers syndrome in ∼50% of patients. Its broad morphologic spectrum and nonspecific immunohistochemical profile has resulted in misclassification in the past as a variety of other neoplasms including those of wolffian, sex cord-stromal, mesothelial, and epithelial derivation. This review focuses on the spectrum of adnexal neoplasms that may develop in Peutz-Jeghers syndrome, with particular emphasis on STK11 adnexal tumor and its differential diagnosis.

Clinicopathological characteristics of invasive stratified mucinous carcinoma of the cervix and the expression and clinical significance of SLC7A11, SLC3A2 and PD-L1.

Invasive Stratified Mucin-producing Carcinoma (ISMC) of the cervix is a newly named cervical adenocarcinoma associated with Human Papilloma virus (HPV). Due to its relative rarity, clinical data, pathological features, and molecular characteristics of ISMC are still under exploration. This study aims to retrospectively analyze the clinical data and pathological features of ISMC patients, summarizing the clinical and pathological morphological characteristics of ISMC. Immunohistochemistry for SLC7A11, SLC3A2, and PD-L1 will be performed on tumor tissues from ISMC patients to preliminarily explore potential therapeutic targets for ISMC. We retrospectively reviewed the electronic medical records and pathological slides of 22 ISMC patients, and performed immunohistochemical staining for solute carrier family 7 member 11 (SLC7A11), solute carrier family 3 member 2 (SLC3A2), and programmed death-ligand 1 (PD-L1). The patients were aged between 31 and 70 years old. The most common symptoms were abnormal vaginal bleeding and unusual vaginal discharge. HPV testing indicated that the infection rate of HPV type 18 was the highest. All patients underwent extensive hysterectomy and pelvic lymph node dissection. The progression-free survival (PFS) ranged from 3 to 112 months, with a postoperative recurrence rate of 22.7% (5/22). ISMC exhibited diverse characteristic microstructures. Immunohistochemistry results showed that the positive rates of SLC7A11 and SLC3A2 were both 91.0% (20/22). The staining intensity of SLC7A11 in frequent ISMC recurrence cases was significantly stronger than in non-recurrent ISMC cases. PD-L1 positivity was observed in 86.4% (19/22) of cases, defined as having a Combined Positive Score(CPS)≥1. ISMC demonstrates a high rate of lymph node metastasis and a high recurrence rate, indicating strong invasiveness. Additionally, ISMC exhibits a wide morphological spectrum. SLC7A11, SLC3A2, and PD-L1 are all highly expressed in ISMC tissues. The high expression of SLC7A11 may indicate a high recurrence rate for ISMC. Immunotherapy with checkpoint inhibitors and iron death-related treatments show potential in the treatment of ISMC, with SLC7A11, SLC3A2, and PD-L1 serving as potential therapeutic targets for ISMC.

A Case of NTRK Fusion Corpus Sarcoma With Pseudobiphasic Growth Pattern and Literature Review.

The incidence of neurotrophic tyrosine kinase receptor (NTRK) fusion uterine sarcoma is extremely low, and reports have been mostly focused on cases localized to the cervix. So far, only 4 cases have been reported of the uterine corpus. In this study, we reported a case of NTRK fusion corpus sarcoma. This study aimed to expand the morphologic spectrum of this tumor, which showed adenosarcoma-like features not previously described. The tumor was confined to the uterine corpus, polypoid growth, comprised predominantly of a fascicular proliferation of spindle cells, entrapping benign endometrial glands, and exhibited a pseudo-biphasic growth pattern. The tumor showed coexpression of S-100, CD34, and pan-Trk by immunohistochemistry, DNA-sequencing identified TPR-NTRK1 gene fusion and AKT1(E17K) mutation. Four cases of NTRK fusion corpus sarcoma were reviewed. The clinicopathologic features, immunohistochemical phenotype, molecular testing, and prognosis of 5 cases including this one were summarized and analyzed. Most cases exhibited an infiltrative g rowth pattern and showed mild or moderate cytologic atypia. The potential for these tumors to be misclassified as uterine adenosarcoma or other uterine mesenchymal tumors. The diagnosis relies on pan-Trk, S-100, CD34 immunohistochemistry, and molecular testing. Surgical resection is the mainstay of treatment for most patients. Distinguishing these tumors from morphologic mimics is significant because patients with advanced-stage disease may be treated with TRK inhibitors.

MorphoGlia, an interactive method to identify and map microglia morphologies, demonstrates differences in hippocampal subregions of an Alzheimer's disease mouse model.

Microglia are dynamic central nervous system cells crucial for maintaining homeostasis and responding to neuroinflammation, as evidenced by their varied morphologies. Existing morphology analysis often fails to detect subtle variations within the full spectrum of microglial morphologies due to their reliance on predefined categories. Here, we present MorphoGlia, an interactive, user-friendly pipeline that objectively characterizes microglial morphologies. MorphoGlia employs a machine learning ensemble to select relevant morphological features of microglia cells, perform dimensionality reduction, cluster these features, and subsequently map the clustered cells back onto the tissue, providing a spatial context for the identified microglial morphologies. We applied this pipeline to compare the responses between saline solution (SS) and scopolamine (SCOP) groups in a SCOP-induced mouse model of Alzheimer's disease, with a specific focus on the hippocampal subregions CA1 and Hilus. Next, we assessed microglial morphologies across four groups: SS-CA1, SCOP-CA1, SS-Hilus, and SCOP-Hilus. The results demonstrated that MorphoGlia effectively differentiated between SS and SCOP-treated groups, identifying distinct clusters of microglial morphologies commonly associated with pro-inflammatory states in the SCOP groups. Additionally, MorphoGlia enabled spatial mapping of these clusters, identifying the most affected hippocampal layers. This study highlights MorphoGlia's capability to provide unbiased analysis and clustering of microglial morphological states, making it a valuable tool for exploring microglial heterogeneity and its implications for central nervous system pathologies.

Muscle-invasive and metastatic urothelial carcinoma from a pathological point of view

Muscle-invasive and metastatic urothelial carcinoma is a heterogeneous disease with a broad morphological and molecular spectrum. The amendment of the WHO classification has resulted in some changes in the nomenclature and classification of muscle-invasive and metastatic urothelial carcinomas. Due to the increasing individualisation of therapeutic options, the correct diagnosis of morphological variants of urothelial carcinoma, which are associated with specific molecular alterations, is becoming more and more important. The morphological variants also correlate with molecular subtypes of urothelial carcinoma. In addition, both morphological and molecular subtypes are associated with immunological and other molecular characteristics that could be relevant for modern immunotherapies or antibody-drug conjugates, e.g. in the form of PD-L1 and NECTIN-4 status. With the pending approval of erdafitinib (FGFR3 inhibitor), molecular tumour boards for patients with metastatic urothelial carcinoma will also become more important in the future.

The Spectrum of Cutaneous Granulomatous Inflammation and Detection of Rubella Virus in Skin Biopsies of Patients With Common Variable Immune Deficiency.

There is a known association between common variable immunodeficiency (CVID) and granulomas in multiple organ systems, including the skin, lung, liver, and spleen. Rubella virus has also been detected within cutaneous granulomas in both immunocompetent and immunocompromised hosts. We present a retrospective case series of patients with CVID and granulomatous skin disease and describe the spectrum of clinical and histopathologic features, including the status of rubella virus in the cutaneous granulomas. We retrospectively reviewed the clinical and histopathological characteristics of patients diagnosed with CVID at our institution, with cutaneous findings and skin biopsies available for review between 1990 and 2023, demonstrating granulomatous inflammation. Eight patients met the inclusion criteria. The most common histopathologic pattern was palisaded granulomatous inflammation, seen in five of eight cases. Three cases showed strictly sarcoidal granulomas. Background inflammation was peri-granulomatous (8/8) and the predominant background inflammatory cell type was lymphocytic (6/8). Rubella virus testing was performed for seven of eight cases and found to be positive in one case. Cutaneous granulomatous disease in CVID can present with a spectrum of clinical morphologies, granulomatous patterns, and variable rubella virus persistence. Dermatopathologists should be aware of the spectrum of findings when considering cutaneous CVID-related granulomatous disease in the differential diagnosis.

Right ventricle-dependent coronary circulation in pulmonary atresia with intact ventricular septum. About three patients without coronary ostium atresia. Is a transient percutaneous decompression maneuver necessary?

Pulmonary atresia with intact ventricular septum (PA-IVS) is a rare congenital heart disease characterized by a wide morphological spectrum that can be associated with abnormalities in the coronary circulation such as sinusoids, fistulas, stenosis or atresia. Some patients do not present ventriculo-coronary fistulas or intramyocardial sinusoids, other patients do present ventriculo-coronary connections, but only some of the latter will have right ventricle-dependent coronary circulation (RVDCC); timely establishment of the diagnosis of RVDCC is essential, since the prognosis of these patients is generally fatal. There are reports of patients with this type of coronary circulation (RVDCC) who were undergone to univentricular physiology, but this treatment option remains controversial, so the purpose of this manuscript is to share three cases with PA-IVS and RVDCC, their outcome and the reflections they provide us. We conducted a cross-sectional, descriptive, observational study of patients with PA-IVS and RVDCC without atresia of the coronary ostium during the study period. Three patients were identified, the clinical and angiographic characteristics and their evolution are described, and a new technique or maneuver for transient percutaneous decompress of the right ventricle is described theoretically for those cases where there is doubt about RVDCC during the angiographic study. An accurate diagnosis regarding the existence of RVDCC is vital. In some cases, the interpretation of angiography for the diagnosis of RVDCC can be difficult to pinpoint and in many cases, it can be operator dependent, however we consider that is necessary to have a technique or maneuver that can objectively and without doubts determine RVDCC in those cases where angiography is not totally conclusive and thus be able to offer the best therapeutic option.

Gastric SMARCA4-Deficient Undifferentiated Carcinoma: A Report of 4 Patients and Literature Review.

SMARCA4-deficient undifferentiated carcinoma (SMARCA4-DUC) of the stomach is a rare gastric tumor that has been receiving increased attention in recent years. With its varied pathological presentations, accurate diagnosis can be challenging. In order to improve our understanding of this aggressive neoplasm, we have carefully documented and analyzed 4 patients with gastric SMARCA4-DUC, adding to the overall knowledge of this uncommon malignancy. The patients were all men, with an average age of 69 years (range 57-76 years). The tumors were located in the gastric antrum (2 patients), the gastric body (1 patient), and the cardia (1 patient). Microscopically, the 3 surgical specimens exhibited similar morphological features: large to medium sized tumor cells, round, irregular to epithelioid undifferentiated cells in solid sheets or discohesive nests, with no obvious stromal reaction. In one patient, short spindle cells arranged in reticular, pseudopapillary, and disorderly patterns were observed amidst extensive interstitial edema. Some areas displayed a lymphoma-like starry sky phenomenon. The biopsy specimens showed large cells diffusely distributed in the submucosa, presenting pale pink cytoplasm, fine chromatin, and prominent large red nucleoli resembling melanoma. All 4 patients demonstrated BRG1 (SMARCA4) loss, INI1 (SMARCB1) retention, and focal positivity for epithelial markers (AE1/AE3 or epithelial membrane antigen). Three patients had clinically advanced (stages IIIC-IV) disease. Follow-up revealed that 1 patient deceased within 4.8 months. This article expands the morphological spectrum of this cancer, providing new insights for accurate cancer diagnosis.

Divergent lineage trajectories and genetic landscapes in human gastric intestinal metaplasia organoids associated with early neoplastic progression

BackgroundGastric intestinal metaplasia (IM) is a precancerous stage spanning a morphological spectrum that is poorly represented by human cell line models.ObjectiveWe aim to establish and characterise human IM cell models...

Aggressive Malignant Ossifying Fibromyxoid Tumor With a Rare PHF1::FOXR2 Fusion: A Case Report and Literature Review

Ossifying fibromyxoid tumor (OFMT) is a rare soft tissue neoplasm of uncertain origin, exhibiting a wide clinical and morphological spectrum. It ranges from benign forms, which typically behave indolently, to malignant lesions with significant recurrence and metastatic potential. The majority of OFMTs harbor PHF1 gene rearrangements, with EP400 being the most common fusion partner. Herein, we present a patient with malignant metastatic OFMT, with the very rare PHF1::FOXR2 fusion, and discuss the potential clinical implications of this genetic alteration.

Neuroendocrine Tumors in Horseshoe Kidneys: A Review of the Literature With Report of a Novel Finding Expanding Their Morphologic Spectrum

Horseshoe kidney is a rare congenital anomaly with an unusually higher frequency of neuroendocrine tumors. Symptoms are rare, and, in most of the cases, are incidentally diagnosed. The clinical behavior of these tumors is heterogeneous and can be difficult to predict based on histology alone. Necrosis and percentage of Ki-67 may have a role in prognosis. Almost all tumors are carcinoids (well-differentiated neuroendocrine tumors) observed at an early age and with no sex dominance. It is not known the reason for the higher frequency of neuroendocrine tumors in horseshoe kidneys and the histogenesis is unknown. One of the hypotheses supports that renal carcinoid tumors may arise from neuroendocrine cells within foci of metaplastic or teratomatous epithelium within the kidney. With consonance with this hypothesis, there are reports of carcinoids in horseshoe kidneys associated with a cystic lesion lined by the intestinal epithelium, with mucinous differentiation and osseous metaplasia, arising in a mature teratoma of the kidney, arising within mature teratoma and clear cell renal cell carcinoma, with a mucinous cystadenoma element, and arising within mature cystic teratoma synchronous with primary adenocarcinoma. There is only one reported large cell neuroendocrine carcinoma of a horseshoe kidney in a 57-year-old Chinese woman. Herein, we report a patient that to the best of our knowledge is the first case of a combined well-differentiated neuroendocrine tumor and large-cell neuroendocrine carcinoma with rhabdoid features in horseshoe kidney. The histologic component of rhabdoid features expands the morphologic spectrum of neuroendocrine tumors in the horseshoe kidney. We provide a comprehensive review of the literature summarizing pertinent key clinical and pathologic aspects.

Expanding the Morphologic Spectrum of ANKRD26-Related Thrombocytopenia-2: A Case Series

Expanding the Morphologic Spectrum of ANKRD26-Related Thrombocytopenia-2: A Case Series

Clinicopathologic features and outcomes of hepatic inflammatory pseudotumour (IPT) and hepatic IPT-like lesions.

Hepatic inflammatory pseudotumours (IPTs) are nonneoplastic hepatic masses characterized by variably fibroblastic stroma and inflammatory infiltrate, hypothesized to arise as part of a response to infection or prior surgery. The aim of this study was to evaluate the clinicopathologic features and outcomes of biopsy-proven hepatic IPT as well as other cases with IPT-like histologic features. A database search at our institution identified cases with a pathologic diagnosis of hepatic IPT (n = 80) between 2000 and 2023. Histologic features (stromal quality, inflammatory cell components, granulomas, and necrosis) were evaluated. Past medical and surgical history, microbiologic studies, and outcomes were reviewed retrospectively. Patients frequently had a past medical history of malignancy (34%), biliary disease (15%), or prior intraabdominal surgery (24%), and often presented with multifocal hepatic lesions (36%). Variable inflammatory backgrounds were present, including histiocytic (36%), lymphoplasmacytic (34%), or neutrophilic (24%). Specific organisms were identified in 15% of cases, most commonly Klebsiella and Staphylococcus species. Most patients with available clinical follow-up demonstrated radiologic resolution and/or had repeat negative biopsy; a minority of patients (8%) were subsequently diagnosed with neoplastic hepatic lesions. No significant association was seen between histologic features and the subsequent clinical or pathologic diagnosis of hepatic neoplastic lesions. Hepatic IPT is a heterogeneous entity that can present in a variety of clinical scenarios and show a wide morphologic spectrum. These lesions often regress spontaneously or with antibiotics. A subset of cases with hepatic IPT-like histologic features were subsequently diagnosed with malignancy, emphasizing the need for continued follow-up and repeat biopsy depending on clinical and radiologic features.

Apocrine variant of intraductal carcinoma of the parotid gland with sebaceous-like differentiation: expanding morphological and molecular spectrum of an enigmatic entity.

Intraductal carcinoma (IDC) is a rare tumor of the salivary glands. Here, we report a unique case of apocrine IDC of the parotid gland of a 60-year-old male, exhibiting a striking sebaceous-like differentiation. Microscopically, the tumor displayed a papillary growth pattern with apocrine cells (AR-positive; S100/SOX10-negative) and distinct areas harboring clear, vacuolated cells resembling sebaceous cells (CK7/S100/SOX10-positive; AR negative). Molecular genetic analysis revealed mutations in AKT1 and BRAF genes. An AKT1 gene mutation has earlier been described in sclerosing polycystic adenoma (SPA), suggesting a possible link between IDC and SPA, while BRAF V600E mutations were reported in an oncocytic subtype of IDC, but not in the apocrine one. Since IDC is an indolent disease, its recognition is a key to prevent unwarranted overtreatment. Further evidence is needed to determine whether apocrine IDC with sebaceous-like differentiation represents a novel morphological variant of the apocrine subtype of IDC or a novel salivary gland entity.