ECP 2023 Abstracts

S180 Virchows Archiv (2023) 483 (Suppl 1):S1–S391 13 months of growth. Physical examination revealed a 2,2 cm firm nodule. A shave biopsy of the lesion was performed. Results: Macroscopic examination revealed a skin-coloured nodule. Histologic study demostrated a proliferation of epithelial cells with oval nuclei, small nucleoli, and abundant granular eosinophilic cytoplasm that formed areas of ductal differentiation, acquiring a cribriform pat- tern. Intraluminal spaces showed variable morphology, some of them with micropapillae formation and a positive periodic acid-Schiff (PAS) staining of a decapitation secretion was observed. Immunohistochemi- cal studies were positive for CKAE1/AE3, CK7, CK8.18, EMA, CEA, GCDFP15, AR, racemase, NKX3.1, GATA3, BerEP4, P53, CD57, PSA and HER2, with negative results for CK20, CK5/6, ER/PR, CD117, S100, P63, P40, calretinin, PAX8, CDX2, SMA, calponin, CD56, chro- mogranin and synaptophysin. Conclusion: Diagnose of PCCC always requires ruling out a cutaneous metastasis of a primary prostatic, breast or colorectal adenocarcinoma. Although immunohistochemical study is useful in guiding the diagno- sis, its value is limited and metastatic disease may be indistinguishable histologically and immunohistochemically from a primary PCCC. E-PS-05-004 Chronic granulomatous periannexal dermatitis with tuberculoid leprosy morphology S. Blasco Muñoz*, A. Ortiz González, A. Sánchez Espinosa, C.A. Capozzi, D. Pérez Parra, E. Guillén Saorín, A. Buendía Alcaraz, M.I. De la Hera Matute, S. Ortiz Reina *Complejo Hospitalario Universitario de Cartagena, Spain Background & objectives: A 59-year-old male Moroccan patient consulted for nail lesions. Suffered from seronegative arthritis with suspected erythema annulare centrifugum, distal sensory-motor axonal polyneuropathy and osteomyelitis with amputation of distal phalanx of the 2nd and 3rd fingers of the right hand. Methods: The lesion was biopsied, showing epidermis with signs of atrophy and dermis with chronic perivascular inflammatory infil- trate and granulomatous reaction around the piloerector and perineu- ral muscles with partial or total destruction of them. Cytologically, granulomata consisted of small accumulations of small epithelioid histiocytes and giant cells with few surrounding lymphocytes without atypia or necrosis. Results: In addition to histological examination with hematoxylin- eosin, histochemical techniques are performed with the FITE tech- nique (modified Ziehl-Neelsen staining technique that stains acid- fast bacilli, useful in the identification of mycobacterium leprae) and immunohistochemical techniques such as S100 (4C4.9), that expose peripheral nerves numerous acid-fast bacilli that occupy and partially destroy them. Leprosy (also known as Hansen’s disease) is an infec- tious disease caused by Mycobacterium leprae and Mycobacterium lepromatosis that affects the skin and peripheral nerves, and if not treated in its early stages, can cause progressive and permanent lesions of the skin, nerves, limbs and eyes, causing paralysis and irreversible disabilities. Conclusion: Although the incidence in Spain has been decreasing in recent years, this does not imply a decrease in its transmission, but in the awareness of the possibility of this diagnosis. As pathologists we must know the histopathological characteristics of this disease in order to understand it and keep it in mind in the differential diagnosis with other granulomatous dermatitis. E-PS-05-005 p14 and p16 absent immunoexpression in the assessment of cutane- ous familial and multiple primary melanoma – an Eastern-Euro- pean cohort study L. Bosoteanu*, E. Gheorghe, M. Aschie, G.C. Cozaru, M. Deacu, C.I. Oră ș anu, M. Bo ș oteanu *Department of Dermatology, “Elias” Emergency University Hospital, Bucharest, Romania, Institute of Doctoral Studies, Doctoral School of Medicine, “Ovidius” University of Constanţa, Constanţa, Romania Background & objectives: CDKN2A mutations represent a relatively common scene in the framework of melanoma, situated in direct rela- tionship with p14 and p16 alterations. This study aims to identify the role of immunohistochemistry in establishing diagnostic particularities of familial and multiple primary melanoma. Methods: A 5-year retrospective cross-sectional study was conducted on 23 patients with cutaneous familial or multiple primary melanomas. Tis- sue samples were examined by noting clinicopathological characteristics (anatomical site, melanoma subtype, Breslow index, mitotic rate, lym- phovascular/perineural invasion) and BRAF status. Nuclear and/or cyto- plasmic distribution of p14 and p16 expression on 4 μm-thick sections was evaluated, with focus on those with immunohistochemical negativity. Results: 11 samples displayed lost p14/p16 immunoexpression. Exclu- sive p16-absent cases (n=7) were more frequently associated with dis- tant metastases (85.71%), compared to 50% of the 4 specimens that lost p14 expression. The average Breslow value correlated with p16 and p14 loss was 6.79 mm and 5.37 mm, respectively. p16-absent specimens encompassed superficial spreading (SSM, 42.85%), nodular (42.85%) and acral melanomas (14.28%), among which 71.42% were ulcerated. The group with p14 loss totalled 2 SMMs and 2 nodular melanomas, with ulceration in 25%. p16-negative cases harboured an average mitotic rate of 5.28/mm2, versus the value of 2/mm2 in patients with absent p14. 50% of p14-negative and 42.85% of p16-negative specimens were BRAF-mutated. Conclusion: This analysis highlights the value of p16 immunohisto- chemical absence as a predictor for aggressive biological behaviour and unfavourable prognosis in familial and/or multiple primary melanomas, in comparison with the loss of p14, regardless of the histopathological subtype. These discoveries are believed to initiate tailored diagnostic and therapeutic algorithms for the Eastern-European population with CDKN2A-mutated melanomas. More studies are necessary to develop specific therapies for patients with these characteristics, depending on the molecular and immunohistochemical particularities of affected proteins. Funding: The paper was funded by Grant Competition in the Medical Field 2022, Contract no. 4/05.10.2022, registered at “Ovidius” Uni- versity of Constanta under no. 15136/05.10.2022. E-PS-05-006 The prognostic significance of skin eosinophil counts in bullous pemphigoid Ö. Bülbül*, E. Tekin, F. Canaz, E. Yılmaz, B. Öztürk, H. Kaya Erdoğan *Eskişehir Osmangazi University, Faculty of Medicine, Departmant of Pathology, Turkey Background & objectives: Bullous pemphigoid is the most common vesiculobullous autoimmune disease and half of the patients show clinically peripheral eosinophilia. We aimed to analyse the relation between tissue eosinophil count and peripheral eosinophilia, mucosal involvement, disease severety and treatment response. Methods: The skin biopsies of 77 bullous pemphigoid patients were reevaluated. Tissue eosinophil count was used to classify patients as having low (1-20 eosinophils/HPF) or high (>20 eosinophils/HPF) eosinophil counts. Other data, including peripheral blood eosinophilia, mucosal involvement, treatment response, lesion severity, and demo- graphics, were also recorded. Results: The mean age of patients was 75.08 years (range 36-95), and 51.9% were female. Tissue eosinophil count ranged from 1 to 167, with a mean count of 28.79. Peripheral eosinophilia was observed in 39% of patients. Peripheral eosinophilia was significantly correlated with mean tissue eosinophil count (p<0.001), and a negative correlation