Cutaneous Sites Research Articles

Mpox mRNA-1769 Vaccine Inhibits Orthopoxvirus Replication at Intranasal, Intrarectal, and Cutaneous Sites of Inoculation.

The increasing incidence of mpox in Africa and the recent global outbreak with evidence of sexual transmission have stimulated interest in new vaccines and therapeutics. Our previous study demonstrated that mice immunized twice with a quadrivalent lipid nanoparticle vaccine comprising four monkeypox virus mRNAs raised neutralizing antibodies and antigen-specific T cells and were protected against a lethal intranasal challenge with vaccinia virus. Here we extended these findings by using live animal imaging to demonstrate that the mRNA vaccine greatly reduced virus replication and spread from an intranasal site of inoculation and prevented detectable replication at intrarectal and cutaneous inoculation sites. Moreover, considerable protection was achieved with a single vaccination and a booster vaccination enhanced protection for at least 4 months. Protection was related to the amount of mRNA inoculated, which correlated with neutralizing antibody levels. The role of antibody in protection was demonstrated by passive transfer of immune serum pre- or post-challenge to immunocompetent and immunodeficient mice lacking mature B and T cells and therefore unable to mount an adaptive response. These findings provide insights into the mechanism and extent of mRNA vaccine induced protection of orthopoxviruses and support clinical testing.

Patterns of forearm lymphatic drainage to the epitrochlear lymph nodes in 1400 cutaneous melanoma patients.

Variations of hand and forearm lymphatic drainage to upper-arm lymphatic pathways may impact the route of melanoma metastasis. This study compared rates of lymphatic drainage to epitrochlear nodes between anatomic divisions of the hand and forearm to determine whether the anatomic distribution of hand and forearm melanomas affects the likelihood of drainage to epitrochlear lymph nodes. Using a single-institution lymphoscintigraphy database, we identified all patients with cutaneous melanoma on the hand and forearm. A body-map two-dimensional coordinate system was used to classify cutaneous melanoma sites between radial-ulnar and dorsal-volar divisions. Sentinel lymph nodes (SLNs) visualized on lymphoscintigraphy were recorded. Proportions of patients with epitrochlear SLNs were compared between anatomic divisions using χ2 analysis. Of 3628 upper extremity cutaneous melanoma patients who underwent lymphatic mapping with lymphoscintigraphy, 1400 met inclusion criteria. Twenty-one percent of patients demonstrated epitrochlear SLNs. Epitrochlear SLNs were observed in 27% of dorsal forearm melanomas and 15% of volar forearm melanomas (p < 0.001). Epitrochlear SLNs were observed in 31% of ulnar forearm melanomas and 17% of radial forearm melanomas (p < 0.001). Higher proportions of dorsal and ulnar forearm melanomas have epitrochlear SLNs. Metastasis to epitrochlear SLNs may be more likely from melanomas in these respective forearm regions.

A Case of Polyserositis, Chylous Ascites and Hepatitis Induced by Immune Checkpoint Inhibitors.

Oncological therapy with immune checkpoint inhibitors (ICPIs) is frequently associated with immune-related adverse events (irAEs) most involving cutaneous, gastrointestinal and pulmonary sites.

Congenital Disseminated Pyogenic Granuloma: A Case With Numerous Mucocutaneous and Visceral Lesions

Abstract Congenital disseminated pyogenic granuloma (CDPG) is characterized by eruptive disseminated or localized lesions, which may arise spontaneously or secondary to predisposing factors. Even rarer is the occurrence of CDPG with numerous lesions affecting variable organs, which develop during the fetal period. This report describes the case of a 32-week-old fetus presenting with severe hydrocephalus and vascular intracranial and right lung masses on magnetic resonance imaging. Preterm labor occurred at the 32nd week due to preterm premature rupture of membranes, and the newborn died due to cardiac dysfunction within 2 hours postpartum. The subsequent autopsy revealed multiple violaceous to dark red papules, nodules, pedunculated and un-pedunculated mucocutaneous masses, as well as two brain lesions, a lung lesion, a thoracic wall intramuscular mass, and a pyloric mass. Microscopic examination and immunohistochemical evaluation for glucose transporter 1 (GLUT1) confirmed the diagnosis of CDPG. CDPG represents a rare condition with an elusive etiology and limited reports in the literature. Differential diagnosis from multifocal infantile hemangioma, based on GLUT1 negativity of CDPG, is imperative due to differing clinical course and treatment modalities. This report underscores a severe case of CDPG characterized by preterm labor and demise shortly after delivery, notable for its extensive involvement across multiple organs, including the brain, lung, intestine, musculoskeletal system, mucosal, and numerous cutaneous sites.

Therapeutic potential of gelatine methacrylate hydrogels loaded with macrophage-derived exosomes for accelerating angiogenesis and cutaneous wound healing

Extensive studies demonstrate that macrophage response plays an important role in regulating angiogenesis via a paracrine way, which is crucial for skin wound repair. This study isolated and characterized nanosized exosomes from differently polarized macrophages (MΦ), including M0 (naïve), M1 (pro-inflammatory), and M2 (anti-inflammatory) macrophages, and further assessed their impacts on angiogenesis and skin regeneration. Our results indicated that compared to M0 and M1 counterparts, M2 macrophage-derived exosomes (M2-Exos) exhibited a pronounced ability to promote angiogenic ability of of human umbilical vein endothelial cells (HUVECs) by enhancing expression of angiogenic genes and proteins, increasing cell migration, and improving tubulogenesis. Bioinformatics analyses suggested that the distinct angiogenic potentials of three MΦ-Exos might be attributed to the differentially expressed angiogenesis-related miRNAs and their target genes such as Stat3, Smad 2, and Smad4. Moreover, these isolated MΦ-Exos were integrated with gelatine methacrylate (GelMA) hydrogels to achieve the sustained delivery at murine full-thickness cutaneous wound sites. In vivo results showed that Gel/M2-Exos significantly augmented angiogenesis, accelerated re-epithelialization, promoted collagen maturity, thereby promoting wound healing. In contrary, Gel/M1-Exos showed the opposite effects. Our findings provided compelling evidence that the polarization status of macrophages significantly affected angiogenesis and wound healing via the miRNA cargos of their derived exosomes. Moreover, this study opens a new avenue for developing nano-scale, cell-free exosome-based therapies in treating cutaneous wounds.Graphical abstract

SOX-10 and TRP-1 expression in feline ocular and nonocular melanomas.

In felines, ocular and nonocular melanomas are uncommon tumors that represent a diagnostic challenge for pathologists, especially when amelanotic. To date, the immunohistochemical diagnostic panel in cats is based on specific melanocytic markers (Melan-A and PNL2) and a nonspecific but sensitive marker (S100). In human medicine, SOX-10 is reported to be a sensitive antibody for the detection of melanoma micrometastasis in the lymph node. TRP-1, an enzyme involved in melanogenesis, has recently been used in humans and dogs as a specific melanocyte marker. The aim of this study was to evaluate the cross-reactivity and the expression of SOX-10 and TRP-1 antibodies in feline normal tissue and melanocytic tumors. Thirty-one cases of ocular, cutaneous, and oral melanomas were retrospectively evaluated and confirmed by histopathological examination and by immunolabeling with Melan-A and/or PNL2. SOX-10 nuclear expression in normal tissues was localized in epidermal, subepidermal, hair bulb, and iridal stromal melanocytes and dermal nerves. In melanomas, nuclear expression of SOX-10 was detected in ocular (11/12; 92%), oral (6/7; 86%), and cutaneous sites (12/12; 100%). TRP-1 cytoplasmic immunolabeling in normal tissue was observed in epidermal and bulbar melanocytes and in the lining pigmented epithelium of the iris and in its stroma. Its expression was positively correlated to the degree of pigmentation in the tumor and was observed in 75% of ocular (9/12), 43% of oral (3/7), and 33% of cutaneous melanomas (4/12). This study demonstrated the cross-reactivity of SOX-10 and TRP-1 antibodies in feline non-neoplastic melanocytes and their expression in ocular and nonocular melanomas.

Abstract 3833: Primary cutaneous diffuse large B-cell lymphoma-leg type and clinicopathologic determinants of survival: Analysis of a pooled database

Abstract Background: Primary Cutaneous Diffuse Large B-cell Lymphoma-Leg Type (PCDLBCL-LT) is a rare but non-indolent subtype of B-cell lymphoma. While most PCDLBCL-LT starts over the lower extremities, some cases may present at other cutaneous sites. The determinants of survival outcomes in this disease are not very well defined. Therefore, we conducted this pooled database analysis to identify the prognostic factors, clinicopathological characteristics, and therapeutic strategies that influence survival in this disease. Methods: To study the demographic characteristics, molecular and immunohistochemical signatures, therapeutic interventions, survival, and prognostic factors, we compiled a pooled database of 122 cases that fit the diagnostic criteria for PCDLBCL-LT. Kaplan-Meier survival curves were constructed. Cox proportional hazards model and Log-rank tests were used to assess the influence of demographic and clinicopathologic factors on overall survival (OS) and disease-free survival (DFS). Results: A total of 122 patients with confirmed PCDLBCL-LT were identified. The median age was 76. There was a male preponderance with M:F of 2.4. Seventy-three percent involved the extremities. The median duration of symptoms before diagnosis was 3.5 months. Involvement of lymph nodes, bone marrow, bone, and CNS occurred in 11%, 3%, 4%, and 3%, respectively. Constitutional symptoms were reported in 5%. The median OS and DFS of the whole group were 39 and 32 months, respectively. Patients younger than 70 had better median DFS (NR vs. 24 months, p=0.02) with a non-significant better median OS. Lymphadenopathy (45 vs. 18 months, p=0.006) and stage T3 compared to T1/T2 (16 vs 41 months, p=0.006) were associated with worse OS. Sex, constitutional symptoms, IHC phenotype, extra-lymphatic/extra-cutaneous organ involvement, and histologic cutaneous patterns did not impact OS. Compared to no treatment, chemotherapy, XRT+/-surgery, and stem cell transplant had numerically better OS without reaching statistical significance (5 vs. 39 vs. 41 vs. NR months, p=0.15). Patients who attained CR as their best response also had a superior median OS compared to responses less than CR and none (61 vs. 23 vs. 11 months, p&amp;lt;0.0001). Conclusion: This study presents updated clinicopathologic data from a large, pooled cohort of patients with PCDLBCL-LT. It identifies age, lymph node involvement, T stage, type of therapy, and quality of response to treatment as critical determinants of OS. Citation Format: Philip A. Haddad, Millicent Amankwah. Primary cutaneous diffuse large B-cell lymphoma-leg type and clinicopathologic determinants of survival: Analysis of a pooled database [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3833.

Lipschütz ulcers due to SARS-CoV-2 infection: a neglected diagnosis in emergency room.

Primary acute genital ulcers, or Lipschütz ulcers (LU), are nonsexually transmitted, painful, self-limiting, nonrecurrent vulvar ulcers with unclear pathogenesis, representing a challenging diagnosis in emergency setting. LU have recently been described in association with severe acute respiratory syndrome coronaVirus 2 (SARS-CoV-2) infection and vaccination. The aim of this study is to describe 2 cases of LU due to SARS-CoV-2 infection, highlighting the diagnostic process, differential diagnosis, disease course, and management options. We describe 2 young females (12 and 9 years old) who presented to pediatric emergency room with the sudden onset of well-demarcated, painful, vulvar ulcers with fibrinous necrotic center. Both patients tested positive to SARS-CoV-2 nasal swab, and, at physical examination, no other lesions were found in other cutaneous or mucosal sites. Sexual abuse was excluded in both cases, as well as infectious and autoimmune diseases. Supportive analgesic therapy was administered, and complete remission of lesions was observed at follow-up visits without evidence of scarring. The main limitation of this work is represented by the small number of cases described. Even though extremely rare, LU related to COVID-19 are an emerging entity to be considered in the diagnosis of acute genital ulcerations. Multidisciplinary diagnostic workup of genital ulcers must be established in order to exclude sexual child abuse, to ensure patient safety, and to avoid unnecessary treatment and familial anxiety.

Differences in hidradenitis suppurativa patterns of cutaneous involvement between sexes: Insights from a cross-sectional study

Hidradenitis suppurativa is a chronic, inflammatory condition of the pilosebaceous unit in which patients manifest multiple, painful cutaneous nodules, abscesses and tunnels. These lesions are described to affect the intertriginous zones, however, the condition exhibits significant phenotypic variability. Such variability is influenced by the patients lifestyle, genetic predisposition and sex. In this cross-sectional study, we investigate sex differences in patterns of hidradenitis suppurativa skin involvement, specifically at site of first involvement and most bothersome cutaneous site of involvement.

P921 Maintenance of clinical, biochemical and transmural remission in inflammatory bowel disease patients switching from intravenous to subcutaneous infliximab

Abstract Background Subcutaneous (SC) infliximab (IFX) effectively maintains biochemical, clinical and endoscopic remission in inflammatory bowel disease (IBD) with a comparable safety profile to intravenous (IV) formulation. Transmural healing is considered a desirable long-term treatment endpoint in IBD, especially in Crohn’s disease (CD). Whether switching from intravenous to SC-IFX effectively maintains transmural remission in IBD is still unknown. Methods This is a preliminary report from a prospective multicentre cohort study on IBD patients in clinical and endoscopic remission on IV-IFX treatment switched to SC-IFX. Enrolled patients were followed-up for 12 months, with fecal calprotectin (FC), C-reactive protein (CRP), infliximab trough levels and anti-drug antibodies (ADAs) measured at baseline, at 3, 6 and 12 months. Intestinal ultrasound (IUS) was performed at baseline and every six months. At month 12 a full colonoscopy was performed for mucosal healing assessment. Remission rates and safety profile were subsequently recorded. T-Test and ANOVA for mean comparisons and Kaplan-Meier estimates were used for survival curves. Results 43 IBD patients (69% males) were enrolled, 58% with CD, of whom 52% reported a history of perianal disease. Median disease duration and IFX therapy were 6 (IQR 3-12) and 5 (IQR 2-9) years, respectively. During a median follow-up of 311 (range 122-489) days, clinical remission rate was 98% (Harvey-Bradshaw Index &amp;lt;5 and Mayo score &amp;lt;2). No reactivation of perianal disease was reported. FC and CRP remained stable at each time point (p&amp;gt; 0.05). The median baseline infliximab level was 10.02 ( range 0.1- 41.84) ug/ml. Undetectable infliximab levels (&amp;lt;1 ug/ml) and positive ADAs were found in 6 and 14 patients, respectively; at 3 months, a significant increase in infliximab levels (mean increase 27.5 ng/ml; ± 12.5 SD; p&amp;lt; 0.001) and a progressive decrease of ADAs titer were observed, despite unchanged SC-IFX dose. At baseline, all patients had normal bowel wall thickness (i.e. ileum ≤ 3mm, colon≤4 mm) and a Limberg score ≤1at IUS; reactive lymphadenopathies were reported in 5 patients and a mild abdominal effusion in 1. No significant changes were shown during follow-up. Mild endoscopic activity was found in 2 out 30 patients who performed follow-up endoscopy. Regarding safety profile 12 mild infectious events, 2 mild cutaneous injection site reaction and 1 non-IBD related hospital admission were observed. Conclusion Switching from IV to SC infliximab in a selected cohort of IBD patients confirmed to be safe and effective in maintaining clinical, biochemical, and transmural remission. IUS is a useful, non-invasive and low-cost tool for periodic disease assessment in this subset of patients.

Presumptive injection-site sarcoma in a white tiger (Panthera tigris tigris): A case report

A 6-year-old female White Tiger (Panthera Tigris Tigris) was presented with a history of a recurrent ulcerating mass on the right lumbar wall which initially, was removed by surgery one year before presentation. Cytological and histological findings were consistent with a cutaneous injection site sarcomas. Immunohistochemistry results revealed that the neoplastic cells were strongly positive for vimentin and weakly positive for alpha-smooth muscle actin (SMA), but negative for Cytokeratin AE1/AE3, s100, and Desmin. Positive staining for vimentin and SMA is consistent with myofibroblast reactivity and reflects a continuous inflammatory response seen in feline injection-site sarcomas. Feline injection-site sarcomas are the most serious adverse effect following injection of the vaccine or some other pharmaceutical substances and should be considered in the differential diagnosis of skin swelling in injection sites in the Felidae family. Limited data are available for these tumors in animals outside of domesticated cats. To the best of our knowledge, there exists no available published information on the injection-site sarcoma in tigers. Similar to domestic felids, this case highlights the importance of considerations and management options in vaccination schedules for the reduction of sarcoma risk in wild felids.

Betapapillomavirus natural history and co-detection with alphapapillomavirus in cervical samples of adult women.

Human papillomaviruses (HPV) of the genus Betapapillomavirus can infect both cutaneous and mucosal sites, but research on their natural history at mucosal sites remains scarce. We examined the risk factors and co-detection patterns of HPVs of the Betapapillomavirus and Alphapapillomavirus genera in cervical samples of the Ludwig-McGill cohort study. We assessed a subset of 505 women from the Ludwig-McGill cohort study from São Paulo, Brazil. Cervical samples over the first year of follow-up were tested for DNA of over 40 alphapapillomavirus types and 43 betapapillomavirus types using a type-specific multiplex genotyping polymerase chain reaction assay. We assessed the risk factors for prevalent and incident betapapillomavirus type detection, and whether types were detected more frequently together than expected assuming independence using permutation tests, logistic regression, and Cox regression. We observed significant within-genus clustering but not cross-genus clustering. Multiple betapapillomavirus types were co-detected in the same sample 2.24 (95% confidence interval [CI]: 1.65-3.29) times more frequently than expected. Conversely, co-detections of alphapapillomavirus and betapapillomavirus types in the same sample occurred only 0.64 (95% CI: 0.51-0.83) times as often as expected under independence. In prospective analyses, positivity to one HPV genus was associated with a nonsignificant lower incidence of detection of types in the other genus. Lifetime number of sex partners and new sex partner acquisition were associated with lower risks of prevalent and incident betapapillomavirus detection. Betapapillomaviruses are commonly found in the cervicovaginal tract. Results suggest potentially different mechanisms of transmission for betapapillomavirus genital infections other than vaginal sex.

Primary Cutaneous Diffuse Large B-Cell Lymphoma-Leg Type Descriptors and Clinicopathologic Determinants of Survival: Analysis of a Pooled Database

Background Primary Cutaneous Diffuse Large B-cell Lymphoma-Leg Type (PCDLBCL-LT) is a rare but non-indolent subtype of B-cell lymphoma. While most of PCDLBCL-LT starts over the lower extremities, some cases may present at other cutaneous sites. The determinants of survival outcomes in this disease are not very well defined. Therefore, we conducted this pooled database analysis to identify the prognostic factors, clinicopathological characteristics, and therapeutic strategies that influence survival in this disease. Methods To study the demographic characteristics, molecular and immunohistochemical signatures, therapeutic interventions, survival, and prognostic factors, we compiled a pooled database of 122 cases that fit the diagnostic criteria for PCDLBCL-LT. Kaplan-Meier survival curves were constructed. Cox proportional hazards model and Log-rank tests were used to assess the influence of demographic and clinicopathologic factors on overall survival (OS) and disease-free survival (DFS). Results A total of 122 patients with confirmed PCDLBCL-LT were identified. The median age was 76. There was a male preponderance with M:F of 2.4. Seventy-three percent involved the extremities. The median duration of symptoms before diagnosis was 3.5 months. Involvement of lymph nodes, bone marrow, bone, and CNS occurred in 11%, 3%, 4%, and 3%, respectively. Constitutional symptoms were reported in 5%. The median OS and DFS of the whole group were 39 and 32 months, respectively. Patients younger than 70 had better median DFS (NR vs. 24 months, p=0.02) with a non-significant better median OS. Lymph node involvement (18 vs. 45 months, p=0.006) and stage T3 compared to T1/T2 (16 vs. 41 months, p=0.006) were associated with worse OS. Sex, constitutional symptoms, IHC phenotype, extra-lymphatic/extra-cutaneous organ involvement, and histologic cutaneous patterns did not impact OS. Compared to no treatment, chemotherapy, XRT+/-surgery, and stem cell transplant had numerically better OS without reaching statistical significance (5 vs. 39 vs. 41 vs. NR months, p=0.15). Patients who attained CR as their best response also had a superior median OS compared to responses less than CR and non-responders (61 vs. 23 vs. 11 months, p&amp;lt;0.0001). Conclusion This study presents updated clinicopathologic data from a large, pooled cohort of patients with PCDLBCL-LT. It identifies age, lymph node involvement, T stage, type of therapy, and quality of response to treatment as critical determinants of OS.

TRPS1 expression in primary and secondary extramammary Paget diseases: An immunohistochemical analysis of 93 cases

Extramammary Paget disease (EMPD) predominantly manifests de novo as primary EMPD, with less than 30 % of cases associated with underlying internal malignancy (secondary EMPD). Differentiating primary from secondary EMPDs based solely on histopathology poses challenges, often necessitating supplementary screening, such as endoscopy or imaging studies, to definitively exclude underlying carcinomas like colonic adenocarcinoma. Recently, TRPS1 immunohistochemistry, initially identified as a sensitive and specific marker for carcinomas and mesenchymal tumors of mammary origin, has been proposed for EMPD. In this study, we conducted a systematic assessment of TRPS1 expression across 93 EMPD cases, comprising 82 primary EMPDs and 11 secondary EMPDs. Our aim was to assess the potential utility of TRPS1 as a marker to differentiate between primary and secondary EMPDs. Our findings revealed that 88 % (72/82) of primary EMPDs displayed TRPS1 expression, while secondary EMPDs consistently lacked TRPS1 expression (100 %; 11/11). Within the primary EMPD group, consistent TRPS1 immunoreactivity was observed in lesions originating outside the perianal region, such as the groin/inguinal area, axilla, and trunk. Interestingly, a majority (91 %; 10/11) of primary EMPDs originating in the perianal region exhibited an absence of TRPS1 expression. Upon excluding cases of perianal primary EMPDs, the sensitivity and specificity of TRPS1 for primary EMPDs reached 100 %. Our findings suggest that TRPS1 expression holds notable sensitivity and specificity for primary EMPDs, particularly when arising from non-perianal cutaneous sites. Hence, in suitable clinical contexts, TRPS1 immunohistochemistry may emerge as a promising and valuable tool for distinguishing primary and secondary EMPDs.

Betapapillomaviruses in p16-Negative Vulvar Intraepithelial Lesions Associated with Squamous Cell Carcinoma.

Approximately 40% of vulvar squamous cell carcinoma (vSCC) cases are etiologically associated with high-risk human papillomaviruses (HPVs) of the alpha genera (α-HPV) that cause other anogenital cancers; however, the etiology of α-HPV-negative vSCC is poorly understood. HPVs of the beta genera (β-HPV) are risk factors for cutaneous squamous cell carcinoma (cSCC) and may be related to carcinomas originating in other cutaneous sites such as the vulva. In this study, we investigate the presence of β-HPVs, with an emphasis on p16-negative squamous lesions adjacent to vSCC. We subjected 28 vulvar squamous intraepithelial lesions adjacent to vSCC for comprehensive HPV genotyping, p16 and p53 immunohistochemistry, and consensus morphology review. Selected cases were subjected to qPCR and RNA in situ hybridization. Clinical data were obtained from medical records. β-HPV DNA was detected in eight of ten p16-negative lesions and three of fourteen p16-positive high-grade squamous intraepithelial lesions. The HPV DNA loads in vulvar squamous intraepithelial lesions ranged between less than 1 HPV DNA copy per cell to more than 100 HPV DNA copies per cell. This is, to the best of our knowledge, the first report of the association of p16-negative vulvar intraepithelial squamous lesions with detection of β-HPVs. These findings expand possible etiologic mechanisms that may contribute to p16-negative lesions of the vulva.

40727 Associations Between Primary Cutaneous Melanoma Site and Metastatic Disease Site

40727 Associations Between Primary Cutaneous Melanoma Site and Metastatic Disease Site

Non-cutaneous syncytial myoepitheliomas are identical to cutaneous counterparts: a clinicopathologic study of 24 tumors occurring at diverse locations.

Cutaneous syncytial myoepithelioma (CSM) is a rare myoepithelioma variant of skin, characterized by intradermal syncytial growth of spindle cells with a distinct immunophenotype of EMA and S100 positivity and infrequent keratin expression. While CSM was first described as a cutaneous tumor, singular non-cutaneous cases have since been reported in bone. We aimed to investigate the clinicopathological features of this variant across all anatomic sites through a large multi-institutional study. We complied a total of 24 myoepitheliomas with syncytial growth from our files. The tumors occurred in 12 male and 12 female patients (M:F = 1:1), with a median age of 31 years (range, 9-69 years). While the majority of tumors (75%, n = 18) occurred in skin, a significant subset (25%, n = 6) arose in non-cutaneous sites, including bone (n = 3), bronchus/trachea (n = 2), and interosseous membrane of tibia/fibula (n = 1). Tumor size ranged from 0.4 to 5.9 cm. Clinical follow-up (7 patients; range 14-202 months; median 56.5 months) showed a single local recurrence 8 years after incomplete skin excision but no metastases; all patients were alive at the time of last follow-up without evidence of disease. Histologically, all tumors were pink at low-power and characterized by a syncytial growth of bland ovoid, spindled, or histiocytoid cells with eosinophilic cytoplasm and prominent perivascular lymphoplasmacytic inflammation. One-third displayed adipocytic metaplasia (8/24). Rare cytologic atypia was seen but was not associated with increased mitotic activity. All tumors expressed S100, SMA, and/or EMA. Keratin expression was absent in most cases. Molecular analysis was performed in 16 cases, all showing EWSR1-rearrangments. In total, 15/15 (100%) harbored an EWSR1::PBX3 fusion, whereas 1 case EWSR1 FISH was the only molecular study performed. Syncytial myoepithelioma is a rare but recognizable morphologic variant of myoepithelioma which may have a predilection for skin but also occurs in diverse non-cutaneous sites. Our series provides evidence supporting a reappraisal of the term "cutaneous syncytial myoepithelioma," as 25% of patients in our series presented with non-cutaneous tumors; thus, we propose the term "syncytial myoepithelioma" to aid pathologist recognition and avoidance of potentially confusing terminology when referring to non-cutaneous examples. The behavior of syncytial myoepithelioma, whether it arises in cutaneous or non-cutaneous sites, is indolent and perhaps benign with a small capacity for local recurrence.

Verruciform Xanthoma: Clinical and Morphologic Spectrum Across Oral, Genital, and Cutaneous Sites.

Verruciform xanthoma (VX) is an uncommon, benign epithelial lesion of the oral mucosa. While this entity can also present extraorally, including on the skin and in anogenital areas, the variation in its histologic features in extraoral sites is not yet well defined. Differences in the demographics and morphologic features of oral versus extraoral VX were assessed to help facilitate the accurate diagnosis and management of this lesion. After obtaining IRB approval, 110 cases of diagnosed VX were retrospectively collected from our institutional archives spanning from 2000 to 2022. Patient age, gender, available medical history, lesion appearance, and duration were obtained for each case. The median age was 55years (range 13-86) with a male-to-female ratio of 1.2:1. The most common oral sites, in descending order, were the palate (n = 24, 22%), buccal mucosa (n = 18, 16%), gingiva (n = 16, 15%), and tongue (n = 13, 12%). Extraoral sites comprised 9% of all lesions, including the scrotum (9), vulva (2), cheek (1), wrist (1), gluteal region (1), and abdominal wall (1). The median size for all lesions was 6.0mm, and extraoral lesions were associated with a 6.7mm larger size compared to oral lesions (B ± SE: 6.7 ± 2.5cm, p = 0.01). The lesions were most frequently pink or white in color and often described as papillary, pedunculated, verrucous, and/or exophytic. Microscopically, the presence of wedge-shaped parakeratosis, keratin projections above the epithelium/epidermis, and associated inflammation significantly differed between oral and extraoral lesions. Prominent wedge-shaped parakeratosis (p = 0.04) and keratin projections above the epithelium/epidermis (p < 0.001) were more prevalent in extraoral lesions. There was no significant link between keratin projections and epithelial atypia (p = 0.44). Familiarity with the broad morphological spectrum of VX, including the presence and degree of wedge-shaped parakeratosis, keratin projections above the epithelium/epidermis, and associated underlying inflammation, will be helpful in diagnosing it in unusual locations.

Primary Cutaneous Adenoid Cystic Carcinoma Of The Chest Wall With Axillary Lymph Node Metastases And Its Management: A Case Report.

Primary cutaneous adenoid cystic carcinoma (PCACC) is a rare form of adenoid cystic carcinoma (ACC) arising commonly from the salivary gland. Less often they originate outside the head and neck region, with the scalp being the commonest cutaneous site in 40% of the cases. The presentation on the chest wall is rare, with no reports to date on axillary lymph node metastases. Here we report a case of a 65-year-old female with previously operated PCACC of the chest wall at a different center, showing uptake on positron emission tomography imaging at the site of surgical scar that w as inconclusive on needle biopsy metastasized to the axillary lymph node confirmed by needle biopsy managed with wide local excision, axillary lymph node dissection, and chest wall reconstruction with keystone island flap. The postoperative outcome was uneventful with no recurrence or axillary complications at one year's follow-up. She was advised to receive adjuvant radiotherapy; however, she refused. To conclude, though PCACC is rare, they can have an aggressive presentation, and a multidisciplinary approach is necessary for a better outcome.

PA12 A case of pustular psoriasis in epidermolytic ichthyosis: coincidence or common pathway?

Abstract An 8-year-old boy with epidermolytic ichthyosis (EI) due to a heterozygous KRT1 mutation presented with a striking bullous skin eruption. Microbiological swabs were sent, and oral antibiotics were prescribed for suspected bullous impetigo. He deteriorated clinically, developing a fever and more extensive pustular rash reminiscent of generalized pustular psoriasis (GPP). Skin biopsies from two distinct cutaneous sites revealed histology strongly supportive of pustular psoriasis. Oral ciclosporin was commenced in addition to intensive topical emollient therapy. Following widespread desquamation, the pustular eruption fully resolved. Recurrence upon weaning of ciclosporin necessitated the introduction of ustekinumab. The rash remains controlled on this therapy. The EI is caused by heterozygous mutations in KRT1 or KRT10, and presents at birth with erythroderma and widespread skin denudation. The erythema and skin fragility abate in early childhood, giving way to prominent hyperkeratosis. Severe palmoplantar keratoderma is seen in those with KRT1 mutations. The GPP is a rare but life-threatening condition characterized by sterile pustules with or without systemic involvement. Interleukin (IL)-36-mediated inflammatory signalling plays a pathogenic role, as evidenced by loss of function mutations in IL36RN, which encodes an IL-36 receptor antagonist (Marrakchi S, Guigue P, Renshaw BR et al. Interleukin-36-receptor antagonist deficiency and generalized pustular psoriasis. N Engl J Med 2011; 365:620–8), and the efficacy of IL-36 receptor inhibitor spesolimab in a recent phase II trial. Both EI and GPP are rare, and the confluence of these entities in this case is striking. Four other cases in the literature describe a GPP-like eruption in patients with congenital ichthyoses. The coexistence of these conditions might be explained by their immunological profiles. Studies of the skin of patients with congenital ichthyoses have shown immune dysregulation with T helper 17/IL-23 skewing, and upregulation of associated inflammatory cytokines, including IL-36γ. The latter encodes for an IL-36 receptor agonist (Paller AS, Renert-Yuval Y, Suprun M et al. An IL-17-dominant immune profile is shared across the major orphan forms of ichthyosis. J Allergy Clin Immunol 2017; 139:152–65). Thus, increased IL-36 receptor agonist activity in congenital ichthyosis could theoretically lead to GPP in genetically predisposed individuals with already upregulated IL-36 receptor-mediated signalling.