ECP 2022 Abstract Book

Virchows Archiv (2022) 481 (Suppl 1):S1–S364 13 Results: We detected 49 lesions which have dysplastic nevus with severe atypia belonging to 32 cases (4%, 5%). The sizes ranged from 3 to 20 mm (mean=8.1 mm). The locations of lesions were as follows; trunk: 38; head: 5; lower extremities: 4, upper extrem- ities:1, unknown: 1. While 43 of 49 lesions showed compound morphology (87.8%), 6 of 49 lesions showed junctional morphol- ogy (12.2%). At the time of the initial diagnosis; 3 patients had malign melanoma (9.3%), 14 patients had multiple dysplastic nevus (43.7%), histopathologically. 8 of the patients with multiple dys- plastic nevus had severe cytologic atypia. The number of dysplastic nevus in these patients was between 2 and 6. Conclusion: Severe atypia is the most important histopathologic feature in terms of malign melanoma progression for dysplastic nevus. For this reason, after recognizing severe atypia in a dys- plastic nevus, screening of all melanocytic lesions of the patients and excision of the lesions which have high risk are recommended. PS-12-007 Expression of IL-22 in tissue specimens of mycosis fungoides is associated with the involvement of FOXP3+ cells and neutro- phils in the microenvironment A. Syrnioti*, E. Georgiou, D. Dimitriadis, D. Papathemeli, A. Patsatsi, T. Koletsa *Department of Pathology, School of Medicine, Aristotle Univer- sity of Thessaloniki, Greece Background & objectives: Recent studies suggest a significant role of the cellular microenvironment, as well as interleukins in mycosis fun- goides (MF). We investigated the cellular microenvironment composi- tion and its potential correlation with Interleukin(IL)-22 and IL-17A expression in MF skin lesions. Methods: We retrospectively collected 16 MF cases of various disease stages, with adequate skin tissue for immunohistochemis- try and available frozen tissue for RT-qPCR. Histological assess- ment of eosinophils, neutrophils, CD20+, CD4+, CD8+, FOXP3+, CD56+ and CD1a+ cells was performed. Expression levels of IL-22 and IL-17 mRNA were measured by RT-qPCR. Statistical analysis was performed using SPSS version 25. Results: The cases included three in patch stage, eight in plaque stage, and five in transformation to high-grade large cell lym- phoma (t-LCL). Overall, eosinophils, neutrophils, and B-lym- phocytes were absent or scarce, with the highest numbers being observed in t-LCL cases. IL-22 and IL-17A tissue levels were higher in early than in advanced stages of the disease. IL-22 levels were associated with IL-17A levels (Pearson’s, r=0.961, p<0.001) and showed a statistically significant correlation with FOXP3+ T-regulatory cells (Pearson’s, r=0.851, p<0.001), as well as with neutrophil density (Pearson’s, r=0.586, p=0.014). No association was found between IL-17A values and the esti- mated cells. Conclusion: MF lesions with t-LCL present a remarkable different microenvironment regarding cellular composition and IL expression levels, compared to early MF. FOXP3+ cells may regulate the expression of IL-22 in the MF microenvironment. Investigating the role of the cellular microenvironment and certain cytokines, including IL-17A, and -22, in MF, can significantly contribute to a better understanding of the pathogenesis and progression of the disease and possibly to novel targeted therapies. PS-12-008 Dermatomyofibroma: a series of five cases C. Buján Bonino, J.M. Suárez Peñaranda* *Department of Pathology, University Hospital of Santiago de Compostela, Spain Background & objectives: Dermatomyofibroma (DMF) is an infre- quent mesenchymal benign tumour of uncertain nature. It usually affects young women and is preferentially located in the upper trunk. Its diagnosis relies on its distinct clinical, histological and immuno- histochemical features. Methods: We retrospectively collected five cases of DMF from the files of the Department of Pathology of the University Hospital of Santiago de Compostela. All cases had blocks and sections avail- able for review. The demographic, clinical and immunohistochemi- cal characteristics of the cases were studied. Results: Cases corresponded to one male and four females, with ages which ranged from 4 to 48 years (average 32). Three cases were located in the shoulder girdle and two in the upper chest. They were all superficially located and diameter was around 1cm. Treatment was conservative resection and no relapses were noted. Histologically, they were constituted by multiple fascicles of regular spindle-shaped cells parallel to the epidermis, showing no mitoses or pleomorphism. Immunohistochemical study was performed in all cases to confirm the diagnosis. Conclusion: DMF are unusual lesions whose clinical and histologi- cal features overlap with those of dermatofibroma (DF). Location in the upper part of the trunk is unusual for DF and histologically, the characteristic disposition of fascicles parallel to the dermo- epidermal junction allow the differential diagnosis. Immunohis- tochemical findings suggest not muscular, but myofibroblastic differentiation. PS-12-009 GATA3 evaluation on primary cutaneous CD30-positive lym- phoproliferative disorders and its mimics A. Vilaia*, A. Cioroianu, M. Busca, G. Turcu, A. Cernat, C. Dumitru, S. Zurac *Colentina Clinical Hospital, Romania Background & objectives: Primary cutaneous CD30+ prolifera- tive disorders (CD30+ LPD) represent second largest subcategory of skin lymphomas. The purpose of the study was to assess the GATA3 expression in CD30+ LPD and its mimics for better characterization of malignant T cell features. Methods: We identified 18 cases of CD30+LPD and 13 cases of pityriasis lichenoides et varioliformis acuta (PLEVA), diagnosed in our department between 2009 – 2022. Immunohistochemical staining was performed on all cases for CD4, CD8, CD30, ALK and GATA3. Results were compared between CD30+ LPD group including lymphomatoid papulosis (LyP) and primary cutaneous anaplastic large cell lymphoma (pcALCL) and PLEVA group. Results: We identified 11 cases of Lyp (2 type A, 2 type B, 2 type C, 4 type D and 1 case of LyP not otherwise specified) and 7 cases of pcALCL. All cases of pcALCL (variable CD4/CD8; CD30+) and three out of four cases of LyP type D (CD4-/CD8+/CD30+) showed diffuse and variable positivity for GATA3 in both CD4 and CD8 dermal T cells and in epidermal extravasated lymphocytes. The rest of LyP and all PLEVA cases stained negative for GATA3. The correlation of the percentage of GATA3+ lymphocytes with CD4/CD8 profile of T cells, subgroups or age showed no statisti- cal significance. Conclusion: GATA3 is a transcription factor associated with LTh2 differentiation and function and activation of CD8+ T cells, and our study showed GATA3 positivity in both CD4 or CD8 pre- dominant CD30+ LPD. The tumour microenvironment remains unclear in CD30+ LPD but GATA3 may play a role in cytokine S131