A Novel Artificial Intelligence-Based Parameterization Approach of the Stromal Landscape in Merkel Cell Carcinoma: A Multi-Institutional Study.

Tumor-stroma ratio (TSR) has been recognized as a valuable prognostic indicator in various solid tumors. This study aimed to examine the clinicopathologic relevance of TSR in Merkel cell carcinoma (MCC) using artificial intelligence (AI)-based parameterization of the stromal landscape and validate TSR scores generated by our AI model against those assessed by humans. One hundred twelve MCC cases with whole-slide images were collected from 4 different institutions. Whole-slide images were first partitioned into 128 × 128-pixel "mini-patches," then classified using a novel framework, termed pre-tumor and stroma (Pre-TOAST) and TOAST, whose output equaled the probability of the minipatch representing tumor cells rather than stroma. Hierarchical random samplings of 50 minipatches per region were performed throughout 50 regions per slide. TSR and tumor-stroma landscape (TSL) parameters were estimated using the maximum-likelihood algorithm. Receiver operating characteristic curves showed that the area under the curve value of Pre-TOAST in discriminating classes of interest including tumor cells, collagenous stroma, and lymphocytes from nonclasses of interest including hemorrhage, space, and necrosis was 1.00. The area under the curve value of TOAST in differentiating tumor cells from related stroma was 0.93. MCC stroma was categorized into TSR high (TSR ≥ 50%) and TSR low (TSR < 50%) using both AI- and human pathology-based methods. The AI-based TSR-high subgroup exhibited notably shorter metastasis-free survival (MFS) with a statistical significance of P = .029. Interestingly, pathologist-determined TSR subgroups lacked statistical significance in recurrence-free survival, MFS, and overall survival (P > .05). Density-based spatial clustering of applications with noise analysis identified the following 2 distinct TSL clusters: TSL1 and TSL2. TSL2 showed significantly shorter recurrence-free survival (P = .045) and markedly reduced MFS (P < .001) compared with TSL1. TSL classification appears to offer better prognostic discrimination than traditional TSR evaluation in MCC. TSL can be reliably calculated using an AI-based classification framework and predict various prognostic features of MCC.

Stromal p16 and SATB2 Expression Does Not Distinguish Atypical Polypoid Adenomyoma (APA) From its Benign Mimics.

Atypical polypoid adenomyoma (APA) is a polypoid biphasic lesion of low malignant potential that arises in the lower uterine segment and uterine corpus. The diagnosis of APA is often challenging on biopsy and curettage specimens, and both benign and malignant processes need to be considered in the differential. Stromal expression of p16 and SATB2 have recently been shown to distinguish APA from myoinvasive endometrioid carcinoma. The authors hypothesized that p16 and SATB2 immunohistochemistry could also aid in the distinction of APA from benign adenomyomatous polyp and endometrioid adenomyoma. The study comprised 10 APAs, 7 adenomyomatous polyps, 11 endometrioid adenomyomas, and 10 myoinvasive endometrioid carcinomas. The majority of APAs showed moderate to strong, diffuse p16 and stromal expression. However, most adenomyomatous polyps and endometrioid adenomyomas also exhibited moderate to strong, focal to diffuse p16 stromal expression. SATB2 showed weak to moderate, focal to diffuse expression in the majority of APAs, adenomyomatous polyps and endometrioid adenomyomas. In contrast, p16 and SATB2 were negative to weak and focal in 90% of myoinvasive endometrioid carcinomas. Our findings demonstrate that p16 and SATB2 may be helpful in the differential diagnosis of myoinvasive endometrioid carcinoma and APA while not useful in separating APA from adenomyomatous polyp and endometrioid adenomyoma.

PD-L1 Expression in HPV-associated Versus HPV-independent Invasive Vulvar Squamous Cell Carcinoma.

Two etiological pathways have been implicated in the pathogenesis of vulvar squamous cell carcinoma (VSCC): a high-risk human papillomavirus (HPV)-associated route and an HPV-independent pathway characterized by TP53 mutations. Programmed cell death ligand 1 (PD-L1) has become increasingly useful in predicting the response to checkpoint inhibitor therapy in squamous cell carcinomas at various anatomical sites. This study aimed to assess the association between PD-L1 expression and the VSCC subtype to evaluate the utility of PD-L1 in prognostication and therapeutic selection based on HPV status. PD-L1 status was assessed using 3 separate metrics for the extent of PD-L1 staining in various cell types: immune cell score, tumor proportion score (TPS), and combined positive score. The study group consisted of 25 HPV-associated and 28 HPV-independent VSCCs. PD-L1 expression was positive in the majority of VSCCs according to all 3 scoring metrics (84.9% by immune cell score, 77.3% by TPS, and 90.6% by combined positive score). PD-L1 expression was observed in the majority of cases in both groups (60%-96.4%). PD-L1 expression using the TPS method was greater in HPV-independent tumors than in HPV-associated tumors ( P = 0.004), and high PD-L1 expression was also more common in the HPV-independent subtype ( P = 0.016 using the TPS method and P = 0.013 using the combined positive score method). Our findings contribute to the growing evidence that PD-L1 is expressed in the majority of invasive VSCCs, and thus may serve as an attractive therapeutic target. PD-L1 expression is higher in HPV-independent tumors, suggesting that this subtype may be more responsive to PD-L1 inhibitor therapy.

Clinical implication of PRAME immunohistochemistry in differentiating melanoma in situ and dysplastic nevus in non-acral nevus-associated melanoma in situ: An institutional experience and meta-analysis.

INTRODUCTION: PReferentially expressed Antigen in MElanoma (PRAME) has shown utility in differentiating benign from malignant melanocytic neoplasms. In this study, we investigated the clinical significance of PRAME expression in dysplastic nevi (DN) and nevus-associated melanoma in situ (MIS). METHODS: We included 172 DN and 38 nevus-associated MIS from our institutional archive. PRAME positive expression was defined as nuclear staining in at least 75% of melanocytes. In addition, relevant studies from PubMed and Web of Science were incorporated into a meta-analysis using the random-effects model to assess PRAME expression in MIS and DN. RESULTS: Our institutional data revealed that 71.1% of nevus-associated MIS cases exhibited positive PRAME expression in the MIS components, whereas all DN components were negative for PRAME. 5.7% of cases diagnosed as DN in our cohort demonstrated diffuse positivity for PRAME. Notably, MIS associated with DN displaying epidermal and dermal components displayed a higher likelihood of PRAME positivity compared to those arising on a background of DN with solely epidermal (junctional) components (84% vs. 46%, p = 0.024). The meta-analysis indicated that the pooled PRAME positivity in MIS and DN was 54.5% and 1.9%, respectively. CONCLUSION: PRAME is a valuable immunohistochemical marker for differentiating MIS from DN, particularly in the context of nevus-associated MIS.

Rapidly Progressive Primary Cutaneous Gamma Delta T-Cell Lymphoma With FYN Gene Alteration.

ABSTRACT: Primary cutaneous gamma delta T-cell lymphoma (PCGDTCL) is a rare type of non-Hodgkin lymphoma accounting for <1% of primary cutaneous T-cell lymphomas. The exact cause of PCGDTCL is not known, however, it is thought that chronic antigen exposure in the skin may lead to immune dysregulation at the site, resulting in abnormal proliferation of mature, post-thymic cytotoxic gamma delta T cells. Mutations are the most common genetic alteration seen in PCGDTCL, while structural abnormalities such as gene fusions are not common. We report a case of PCGDTCL with atypical immunophenotypic features, including expression of CD5 with lack of cytotoxic marker expression, and a structural alteration leading to FYN deletion at exon 8. Recently, it was described that a deletion of the area between FYN exon 8 and TRAF3IP2 intron 2 results in a novel FYN::TRAF3IP2 fusion in peripheral T-cell lymphoma, not otherwise specified. We describe our patient's clinical course, differential diagnosis, and potential implications of FYN deletion on disease pathogenesis. To our knowledge, this is the first report of an FYN structural alteration to be described in PCGDTCL.

Two distinct pathogenic pathways of digital papillary adenocarcinoma - BRAF mutation or low-risk HPV infection.

Digital papillary adenocarcinoma (DPA) is a rare neoplasm that can exhibit local recurrence and distant metastasis. We present a series of eight cases of DPA showing two distinct clinical presentations, morphologies, immunophenotypes, and molecular features. Four cases were characterized by painless, slow-growing nodules located on the digits. The lesions were small, well-defined, and confined in the dermis. Histopathologically, these tumors were composed of glandular structures lined by cuboidal epithelium with luminal papillary infoldings. Only rare mitotic figures and minimal squamoid differentiation were present, and cellular necrosis was absent. All four cases were positive for the BRAF V600E immunohistochemistry but negative for p16, low-risk and high-risk HPV in situ hybridization (ISH). In contrast, the remaining four cases were characterized by painful, rapidly growing masses on the digits. These four lesions were located in the deep dermis and consisted of a solid, tightly packed papillary architecture lined by atypical epithelioid cells with inconspicuous nucleoli. Cellular necrosis, numerous mitotic figures, and prominent squamoid differentiation were seen. All cases were negative for the BRAF V600E IHC. However, they showed strong, patchy to diffuse reactivity for p16 and were positive for low-risk HPV ISH and negative for high-risk HPV ISH. Our findings suggest that the current classification of DPA encompasses tumors that show two discrete pathogenic pathways - BRAF mutation or low-risk HPV infection. DPAs with low-risk HPV infection exhibit aggressive clinical features, high-grade morphology, marked squamoid differentiation, and wild-type BRAF. DPAs with BRAF V600E have less aggressive clinical features, low-grade morphologic findings, mild to absent squamoid differentiation, and negative HPV infection.

Feminising hormone therapy reduces testicular ACE-2 receptor expression: Implications for treatment or prevention of COVID-19 infection in men.

It has been proposed that men hospitalised with COVID-19 be treated with oestrogen or progesterone to improve COVID-19 outcomes. Transgender women (male-to-female) are routinely treated with oestrogen or oestrogen +progesterone for feminisation which provides a model for the effect of feminising hormones on testicular tissue. Our goal was to analyse differences in ACE-2 expression in testicles of trans-women taking oestrogen or oestrogen +progesterone. Orchiectomy specimens were collected from trans-women undergoing gender-affirming surgery, who were taking oestrogen or oestrogen+progesterone preoperatively. For controls, we used benign orchiectomy specimens from cis-gender men. All specimens were stained with H&E, Trichrome (fibrosis), insulin-like 3 antibody (Leydig cell) and ACE-2 IHC. Cells per high-powered field were counted by cell type (Leydig, Sertoli and Germ). Stain intensity was rated on a 0-2 scale. On immunohistochemistry staining for Leydig cells and ACE-2 staining, the oestrogen+progesterone cohort had fewer Leydig cells compared with controls. The oestrogen+progesterone cohort also had greater degree of tissue fibrosis compared with controls and the oestrogen cohort. This work supports the hopeful possibility that a short course of progesterone (or oestrogen+progesterone) could downregulate ACE-2 to protect men from COVID-19 infection.

Assessing a modified-AJCC TNM staging system in the New South Wales Cancer Registry, Australia.

BACKGROUND: In 2017, the New South Wales Cancer Registry (NSWCR) participated in a project, supported by Cancer Australia, aiming to provide national stage data for melanoma, prostate, colorectal, breast, and lung cancers diagnosed in 2011. Simplified business rules based on the American Joint Committee for Cancer (AJCC) Tumour-Node-Metastasis (TNM) stage were applied to obtain Registry-Derived (RD) stage, defined as the best estimate of TNM stage at diagnosis using routine notifications available within cancer registries. RD-stage was compared with Degree of Spread (DoS), which has been recorded for all applicable cancers in NSWCR at a population-based level since 1972, and a summary AJCC-TNM stage group, which has been collected variably since 2006. For each of the five high incidence cancers, we compared the level of improvements RD-staging provided in terms of completeness and accuracy (alignment to more clinically relevant AJCC-TNM) over DoS. METHODS: For each of the five cancers, stage data were extracted from NSWCR pre- and post- RD-staging to compare data completeness across all three staging systems. The alignment between DoS/RD-stage and AJCC-TNM was compared, as were the expected and observed cross-tabulated frequency distributions using a subset of NSWCR data. To determine differences between use of DoS, RD-stage, and AJCC-TNM in an epidemiological analysis, we compared survival models developed from each of the three stage variables. RESULTS: We found RD-staging provided greatest stage data completeness and alignment to AJCC-TNM for prostate cancers, followed by breast, then melanoma and lung cancers. For colorectal cancer, summary stage from DoS was confirmed as an equivalent surrogate staging system to both AJCC-TNM and RD-stage. CONCLUSIONS: This analysis provides an evidence-based approach that can be used to inform decision-making for resource planning and potential implementation of a new stage data field in population-based cancer registries.

aPCC vs. rFVIIa for the treatment of bleeding in patients with acquired haemophilia - a cost-effectiveness model.

BACKGROUND: Acquired haemophilia A (AHA) is an autoimmune bleeding disorder with significant morbidity and mortality. Bleeding AHA patients with high titre inhibitors can be treated with either activated prothrombin complex concentrate (aPCC) or recombinant activated factor VII (rFVIIa). Given that both replacement therapies have inherent benefits and limitations, a cost-effectiveness analysis (CEA) was performed in this population to compare rFVIIa with aPCC. METHODS: In high-titered AHA patients with bleeding treated with either aPCC or rFVIIa, during a 5-day study period, a Markov model was developed such that these patients were transitioned into four different health states: (1) continuous bleeding, (2) thrombosis, (3) stop bleeding and (4) death, with states (2), (3) and (4) modelled as absorbing states. Model parameters, including probabilities, health utility index and costs, were gathered from the medical literature, except for the costs of aPCC and rFVIIa, which were obtained from our institutional data. RESULTS: During the 5-day period, the total treatment cost of rFVIIa was substantially more than the cost of aPCC ($13 635 vs. $1741). The average quality-adjusted life days (QALDs) gained for rFVIIa were slightly lower compared to aPCC (4·08 vs. 4·09). Overall, aPCC prevailed over rFVIIa. Sensitivity analysis confirmed the robustness of the model across tested ranges of all input variables. CONCLUSION: In high-titered AHA patients with bleeding, aPCC is a cost-effective treatment option when compared to rFVIIa. Thus, aPCC may be considered in these patients, if available, and provided there is no clinical contraindication.

Thymol and Carvacrol Affect Hybrid Tilapia through the Combination of Direct Stimulation and an Intestinal Microbiota-Mediated Effect: Insights from a Germ-Free Zebrafish Model.

BACKGROUND: Essential oils (EOs) are commonly used as animal feed additives. Information is lacking on the mechanisms driving the beneficial effects of EOs in animals, especially the role played by the intestinal microbiota of the host. OBJECTIVE: The purpose of this study was to clarify the relative contribution of direct effects of EOs on the physiology and immune system of tilapia and indirect effects mediated by the intestinal microbiota by using a germ-free zebrafish model. METHODS: Juvenile hybrid tilapia were fed a control diet or 1 of 4 treatment diets containing 60-800 mg Next Enhance 150 (NE) (an EO product containing equal levels of thymol and carvacrol)/kg for 6 wk. The key humoral and cellular innate immune parameters were evaluated after the feeding period. In another experiment, the gut microbiota of tilapia fed a control or an NE diet (200 mg/kg) for 2 wk were transferred to 3-d postfertilization (dpf) germ-free (GF) zebrafish, and the expression of genes involved in innate immunity and tight junctions was evaluated in zebrafish at 6 dpf. Lastly, NE was directly applied to 3-dpf GF zebrafish at 3 doses ranging from 0.2 to 20 mg/L, and the direct effect of NE on zebrafish was evaluated after 1 and 3 d. RESULTS: NE supplementation at 200 mg/kg enhanced phagocytosis activity of head kidney macrophages (×1.36) (P < 0.05) and plasma lysozyme activity (×1.69) of tilapia compared with the control (P < 0.001), indicating an immunostimulatory effect. Compared with those colonized with control microbiota, GF zebrafish colonized with NE microbiota showed attenuated induction of immune response marker genes serum amyloid a (Saa; ×0.62), interleukin 1ß (Il1ß; ×0.29), and interleukin 8 (Il8; ×0.62) (P < 0.05). NE treatment of GF zebrafish at 2 and 20 mg/L for 1 d upregulated the expression of Il1ß (×2.44) and Claudin1 (×1.38), respectively (P < 0.05), whereas at day 3 the expression of Occludin2 was higher (×3.30) in the 0.2-mg NE/L group compared with the GF control (P < 0.05). CONCLUSION: NE may affect the immunity of tilapia through a combination of factors, i.e., primarily through a direct effect on host tissue (immune-stimulating) but also an indirect effect mediated by microbial changes (immune-relieving).

Human Epidermal Growth Factor Receptor 2 Overexpression/Amplification in Primary Ovarian Endometrioid Carcinoma.

Human epidermal growth factor receptor 2 (HER2) expression has become increasingly helpful in predicting responses to anti-HER2 agents in gynecological cancers. This study retrospectively analyzed HER2 expression in 48 primary ovarian endometrioid carcinomas. HER2 immunohistochemistry was performed using the Ventana platform (Clone 4B5 monoclonal predilute) following the manufacturer's protocol. HER2 expression was equivocal (score 2+) by image analysis in 2 cases (4.17%) based on the breast cancer criteria. Fluorescence in situ hybridization was negative for HER2 amplification in one case (International Federation of Gynecology and Obstetrics, grade 1) and positive in the other (International Federation of Gynecology and Obstetrics, grade 3). Our findings contribute to the growing evidence that HER2 is overexpressed in a small proportion of ovarian endometrioid carcinoma, and thus may serve as a potential therapeutic target in selected cases.

Multiply Recurrent Composite Hemangioendothelioma of Penis with Histologic Progression to High-Grade Features.

Composite hemangioendothelioma (CHE) is a very rare low-grade malignant vascular neoplasm. Here, we present the first case of it occurring on a penis with two local recurrences over a 9 year span and its progression to a high-grade morphology.

TRPS1 Is Differentially Expressed in a Variety of Malignant and Benign Cutaneous Sweat Gland Neoplasms.

Neoplasms of sweat glands and the breast may be morphologically and immunophenotypically similar. A recent study showed that TRPS1 staining is a highly sensitive and specific marker for breast carcinoma. In this study, we analyzed TRPS1 expression in a spectrum of cutaneous sweat gland tumors. We stained five microcystic adnexal carcinomas (MACs), three eccrine adenocarcinomas, two syringoid eccrine carcinomas, four hidradenocarcinomas, six porocarcinomas, one eccrine carcinoma-NOS, 11 hidradenomas, nine poromas, seven cylindromas, three spiradenomas, and 10 syringomas with TRPS1 antibodies. All of the MACs and syringomas were negative. Every cylindroma and two of the three spiradenomas demonstrated intense staining in cells lining the ductular spaces, with negative to relatively weak expression in surrounding cells. Of the 16 remaining malignant entities, 13 were intermediate to high positive, one was low positive, and two were negative. From the 20 hidradenomas and poromas, intermediate to high positivity was revealed in 14 cases, low positivity in three cases, and negative staining in three cases. Our study demonstrates a very high (86%) expression of TRPS1 in malignant and benign adnexal tumors that are mainly composed of islands or nodules with polygonal cells, e.g., hidradenomas. On the other hand, tumors with small ducts or strands of cells, such as MACs, appear to be completely negative. This differential staining among types of sweat gland tumors may represent either differential cells of origin or divergent differentiation and has the potential to be used as a diagnostic tool in the future.

Claudin-4 Upregulation in Acantholytic and Autoimmune-Mediated Bullous Disorders.

Claudin-4 is a key component of tight junctions, which play an important role in the formation of the epidermal barrier by forming a circumferential network in the granular layer that serves as a gatekeeper of the paracellular pathway. The aim of this study is to illustrate claudin-4 immunohistochemical staining patterns of different blistering disorders. We collected 35 cases, including two Hailey-Hailey disease, one Darier disease, three Grover disease, one acantholytic acanthoma, two warty dyskeratoma, 11 pemphigus vulgaris (PV) including six mucosal PV, and two pemphigus foliaceus. For comparison, we included five cases of normal skin, five eczema, and three bullous pemphigoid cases. Claudin-4 demonstrated weak-to-moderate expression in keratinocytes located in the stratum granulosum, keratinocytes surrounding hair follicles, and adnexal glands. Further, claudin-4 exhibited moderate-to-strong membranous staining in disrupted keratinocytes surrounding and within the acantholytic and bullous areas in 16/22 of the acantholytic cases (not seen in the six cases of mucosal PV) and all three bullous pemphigoids. This finding suggests that claudin-4 is upregulated in these conditions, which may be a compensatory response to the disrupted barrier function. This finding could shed light on the molecular mechanisms underlying disrupted barrier function in blistering disorders, independent of the specific underlying disease mechanism.

Diet-Independent Positive Effects of a Multi-Species Probiotic on the Growth Performance and Resistance against Vibrio parahaemolyticus in White Leg Shrimp.

Probiotic feed additives can support the gut health of shrimp and thereby improve performance, production efficiency and disease resistance. Two experiments in white leg shrimp aimed to investigate the effects of a multi-species probiotic feed supplement (AquaStar®, 3 g/kg feed, Biomin GmbH, Getzersdorf, Austria) in feed formulations with different marine meal levels (32% and 15%) on growth performance and resistance against Vibrio parahaemolyticus. Juvenile shrimp were stocked in a recirculating aquaculture tank system at a density of 20 shrimp/46.8 L and were fed diets with and without the probiotic supplementation for 8 weeks. Afterwards, a bath immersion with V. parahaemolyticus was performed and mortality was observed over a period of 14 days. Independent of the diet formulation, probiotic supplementation significantly improved the survival rate of the shrimp and the specific growth rate while decreasing feed consumption and feed conversion ratio when compared to the control (p ≤ 0.042). After the Vibrio immersion challenge, mortality was significantly decreased by 13.33% with probiotic supplementation in the high marine meal diet experiment (p = 0.042) and numerically decreased by 11.67% in the low marine meal diet experiment (p = 0.133). Overall, the results suggest that the beneficial effects of the probiotic can occur independently of the diet formulation.

Evaluation of the Electronic Clinical Dementia Rating for Dementia Screening.

Importance: The Clinical Dementia Rating (CDR) is a well-validated instrument widely used to detect and stage dementia due to Alzheimer disease. The digital Electronic Clinical Dementia Rating (eCDR) can be remotely self-administered and automatically scored, with potential to facilitate efficient dementia screening and staging. Objective: To evaluate the association of the eCDR with the CDR and other in-clinic assessments for screening older adults for cognitive impairment. Design, Setting, and Participants: This multisite, cross-sectional study used baseline data from a longitudinal, observational study from 2020 to 2023, including up to 3 years of follow-up. Participants were enrolled from 3 Alzheimer Disease Research Centers and the Brain Health Registry. Participants (aged ≥55 years, with a study partner, and no acute or unstable major medical conditions) were recruited during in-clinic visits or by automated emails. Exposures: Participants completed the Uniform Data Set Version 3 (UDS; including the CDR) in supervised clinical research settings, and then completed the eCDR remotely, online and unsupervised, using their own device. Main Outcomes and Measures: The primary outcomes were eCDR scores (item; categorical box and global; continuous box and global), CDR scores (item; categorical box and global), and UDS assessment scores. Associations were evaluated using linear and logistic regressions. Results: A total of 3565 participants were contacted, and 288 were enrolled. Among 173 participants with item-level data (mean [SD] age, 70.84 [7.65] years; 76 women [43.9%]), eCDR to CDR concordance was 90% or higher for 33 items (63%) and 70% to 89% for 13 items (25%). Box (domain) level concordance ranged from 80% (memory) to 99% (personal care). The global score concordance rate was 81%. κ statistics were fair to moderate. Among 206 participants with box and global scores (mean [SD] age, 71.34 [7.68] years; 95 women [46.1%]), eCDR continuous global score was associated with CDR global (categorical) score with an area under the receiver operating characteristic curve of 0.79 (95% CI, 0.70-0.87). Correlations between eCDR and in-clinic UDS assessments were similar to those between CDR sum of box scores and the same in-clinic assessments. Conclusions and Relevance: These findings suggest that the eCDR is valid and has potential use for screening and assessment of older adults for cognitive and functional decline related to Alzheimer disease. Instrument optimization and validation in diverse cohorts in remote settings are crucial for evaluating scalability and eCDR utility in clinical research, trials, and health care settings.

Primary mucoepidermoid carcinoma of the breast arising in adenomyoepithelioma.

Mucoepidermoid carcinoma (MEC) and adenomyoepithelioma (AME) are uncommon neoplasms of the breast that are more commonly noted in the salivary glands. AMEs are benign tumours that are known to undergo malignant transformation. This report describes the first case of a MEC arising in AME in a woman in her 50s.

A Case of Digital Cutaneous Melanocytic Tumor With CRTC1::TRIM11 Fusion.

A cutaneous melanocytic tumor with CRTC1::TRIM11 fusion (CMTCT) was recently described as a novel superficial tumor with melanocytic differentiation and harboring a unique in-frame translocation, CRTC1::TRIM11. This emerging entity can occur at any age and is known to be a low-grade malignant neoplasm with limited follow-up data. There are no available guidelines for the management and treatment of this tumor. This neoplasm has been found in the extremities, head and neck, and trunk. Here, we present the first case occurring on acral digital skin. This case contributes to the growing knowledge surrounding this newly described entity.

Pseudomyogenic Hemangioendothelioma: A Case of a Solitary Lesion With a Very Indolent Clinical Course.

Pseudomyogenic hemangioendothelioma (PMH), also known as epithelioid sarcoma-like hemangioendothelioma, is a rare epithelioid vascular neoplasm predominantly affecting young adult males at an average age of approximately 30 years. This tumor is rare; therefore, detailed information regarding this tumor is still lacking. Here, we report a case of a man in his 20s presenting with left foot pain for about one year. Imaging showed a 2-cm ovoid, cortically based lesion with a lytic defect of the cortex at the fifth metatarsal proximal shaft. Histologically, the lesion presented as an infiltrating proliferation of distinctly myoid-appearing spindled cells with eosinophilic cytoplasm and mildly atypical vesicular nuclei. Scant mitoses were identified with no areas of necrosis. Tumor cells exhibited strong, diffuse cytokeratin expression as well as CD31 and ERG. CD34 was positive in a few tumor cells, and integrase interactor 1 (INI1) retained nuclear expression. No reactivity for S100, desmin, smooth muscle actin (SMA), epithelial membrane antigen (EMA), and CD1a was present. Over half of the patients with PMH develop multifocal lesions, often involving several tissue planes; however, distant metastasis is very infrequent. This patient underwent curettage and internal fixation of the left fifth metatarsal and had no evidence of recurrence or distant metastasis after seven years of follow-up. Our case contributes to the growing knowledge of PMH and sheds light on the prognosis of these lesions.