ECP 2022 Abstract Book

Virchows Archiv (2022) 481 (Suppl 1):S1–S364 13 consistent with the literature. It is interesting that previous studies, pilomatricoma with SATB2 immunohistochemistry did not show positivity. In a recent case report in the literature, SATB2, which was applied to a case of pilomatrical carcinoma and showed positivity, was also expressed in our case. Conclusion: In conclusion, the use of SATB2 in the differential diagnosis of benign and malignant pilomatrical tumours may be considered. Even though the results obtained in this study cannot be generalized, it may be important to study these lesions in large series in terms of giving an idea to clarify the pathogenesis and immunohistochemistry. Considered together with the literature, our case can be a clue for new pathogenetic studies. E-PS-05-018 Clinicopathological cocordance of mycosis fungoides: 10 years of our institutional experience E. Ekren*, N. Koç, Ş. Yaşar, M. Erdal *Haydarpasa Numune Education and Research Hospital, Turkey Background & objectives: Mycosis fungoides (MF) is a disease that can be diagnosed by the collaboration of a clinician and pathologist. Its differential diagnosis includes many other malignant and benign dermatoses. We evaluated the clinicopathological corelations and its importance in this study. Methods: Between 2010 and 2021, 885 skin punch biopsies in which MF was diagnosed histopathologically or with MF in the clinical differential diagnosis were retrospectively analysed. Recurrent biopsies (76) and patients previously diagnosed with MF (17) were excluded from the study. Results: Of the cases, no findings consistent with MF were found in 744 (93,9%) patients, whereas MF was diagnosed histopatho- logically in 48 (6,1%) patients. Among the 744 patients in whom MF was excluded, most common primary provisional diagnoses other than MF were psoriatic dermatitis (15%,116/744) and par- apsoriasis (14%, 110/744), similar to the concordant group in which spongiotic dermatitis (16%, 8/48) and parapsoriasis (14%, 7/48) were leading. Conclusion: When the clinical and histopathological concord- ance was evaluated, it was seen that the most clinically confused cases with mf were spongiotic dermatitis and parapsoriasis. E-PS-05-019 Discrete papular lichen myxoedematosus, a rare case report and review of literature M. Shetty, F. Kubba*, I. Logan *Department of Pathology, Ealing Hospital, London North West University Healthcare NHS Trust, United Kingdom Background & objectives: A 57-year-old Asian female presented with widespread pruritic dark itchy papules occurring over 4 years. Exami- nation showed bilateral, symmetrical grouped waxy 1-2m papules over the dorsa of forearms, back, and shin. She had sickle cell anaemia and beta thalassemia trait. Methods: A skin biopsy from a papule showed focal parakera- tosis, circumscribed superficial dermal mucin deposition and Alcian blue stain confirmed the presence of mucin in the upper dermis. There was no fibroblastic proliferation or fibrosis. A diagnosis of discrete papular lichen myxoedematosus (DPLM) was made. She was treated with topical steroids and urea-based emollients and responded very well with complete resolution. Results: Lichen Myxoedematosus (papular mucinosis) is a rare heterogeneous group of cutaneous mucinoses characterised by an abnormal dermal deposition of mucin, first described by Dubreuilh in 1906 Rongioletti and Rebora describe three sub- groups of LM; generalized LM (scleromyxoedema), a localized form, and an atypical variant, which is further subclassified by Nofal et al. Our case represents a subtype of LM with good response to potent topical steroids and had no association with HIV or hepatitis C infection, which has been rarely reported DPLM has good prognosis, and spontaneous remission occurs on occasions. The clinical differential diagnosis includes lichen amyloidosis. Evolution to scleromyxedema has never previously been documented in this form. Conclusion: We presented a rare case of discrete papular lichen myxoedematosus presenting as bilateral symmetrical waxy papules on the dorsa of forearms, back, and shin. Microscopy showed circumscribed superficial dermal mucin deposition confirmed by Alcian blue, with no fibroblastic proliferation or fibrosis. It represents one of three subgroups of LM. Our case was associated with sickle cell anaemia and thalassemia trait. They respond well to urea-based emollients and ultra-potent topical steroids and usually have good prognosis with rarely reported spontaneous remission. E-PS-05-020 Clear cell hidradenoma of the inguinal area: an unusual case I. Msakni*, R. Aouadi, N. Mansouri, F. Gargouri, M. Ben Thayer, K. Tlili, B. Laabidi *Department of Pathology, Military Hospital of Tunis, Tunisia Background & objectives: Hidradenomas are benign adnexal tumours, usually taking place in the head limbs. Inguinal region is uncommon as a site of occurrence. Through this case, we aim to present this unusual location and discuss histological characteristics of this tumour. Methods: We, herein, present a case of an inguinal hidradenoma. Results: A 46- years old male presented with a painless inguinal cystic large mass growing for 12 years. A surgical removal of the mass had been performed. Gross examination showed a heteroge- neous cystic mass with irregular walls. Histopathological exami- nation showed a largely cystic proliferation. It was composed of layers of cells separated by fine branching vessels and arranged in a lobular pattern. The cells were clear, with abundant cytoplasm and monomorphic nuclei without atypia or mitosis. Immunohisto- chemical study showed that the tumour cells were CK5/6 positive, ACE negative and did not express kidney cell marker PAX8. These findings were consistent with a clear cell hidradenoma. Conclusion: Hidradenomas are rare adnexal tumours. Inguinal localization is extremely rare. Histologically, the tumour has a pre- dominantly clear cells pattern that may be challenging for the diag- nosis. In fact, differential diagnosis, especially, metastatic tumours, should be ruled out using immunohistochemistry and clinical data. Clinical assessment is required to detect possible recurrences. E-PS-05-021 Atypical hidradenoma: a case report Y. Ozerdem*, E. Ucaryilmaz Ozhamam *Erzurum Regional Training and Research Hospital, Turkey Background & objectives: Atypical hidradenoma is an uncommon neoplasm, displaying atypical features in contrast to its benign coun- terpart hidradenoma, including nuclear hyperchromatism and pleo- morphism, giant cells, focal infiltrative growth, necrosis and mitotic activity. S211