ECP 2022 Abstract Book

Virchows Archiv (2022) 481 (Suppl 1):S1–S364 13 present more diagnostic criteria, but also prognostic and therapeu- tic meaningful data. E-PS-02-013 Breast malakoplakia mimicking malignancy: a case report N. Mansouri*, M. Ben Thayer, F. Gargouri, R. Aouadi, K. Tlili, I. Msakni, B. Laabidi *Department of Pathology, Military Hospital of Tunis, Tunisia Background & objectives: Malakoplakia is an uncommon inflamma- tory disease. Breast is extremely rare as a site of occurrence. By this case, we aim to discuss clinicopathological characteristics of this entity and challenges in the diagnosis. Methods: We present a case of breast malakoplakia (BM) in a 35-year-old woman, that mimicked a malignant tumour. Results: A 35-year-old patient, with no medical history, presented to the emergency department with fever and respiratory distress. Rapid SARS-coV-19 testing was negative. The patient underwent a chest-tomography-scan. It showed no signs of SARS-coV-19 pneumopathy. However, it revealed an 8mm mass in the inner upper quadrant of the right breast. A mammography was undertaken and showed round opacities, with spiculated contours and architectural distortions (ACR4), mimicking malignancy. Biopsy revealed a well limited lesion composed of abundant foamy histiocytes and basophilic targetoid intracytoplasmic structures (Michaelis- Gutmann bodies) that were PAS positive. The diagnosis of BM was established. The patient received antibiotherapy with good outcome. Conclusion: Malakoplakia is a very rare inflammatory condition. It results from an acquired defect in the phagocytic bactericidal activity of macrophages. Its occurrence in breast is extremely uncommon with four reported cases in the literature. Clinical pres- entation of BM is non specific. In the case we presented, it did not result in any symptoms and was discovered incidentally. However, it can mimic carcinomatous lesion and be challenging for the diag- nosis. Only histologic examination can confirm the diagnosis and rule out malignancy. E-PS-02-014 Mammary-like carcinoma in an extramammary site: vulvar adenocarcinoma arising from specialized anogenital mammary- like gland. Thinking outside the box. Case report and summary of the literature A. Kovács*, T. Parris, C. Mateoiu, K. Helou, P. Karlsson *Department of Clinical Pathology, Sahlgrenska University Hos- pital, Gothenburg, Sweden Background & objectives: The 68-year-old patient presented with an ulcerous vulvar lesion in 2014 that persisted for 8 months. A highly differentiated endometrium adenocarcinoma without ovarian involvement (FIGO1A) was diagnosed in her hysterectomy/bilateral salpingo-oophorectomy specimen 8 years prior to her vulvar lesion. Methods: An invasive adenocarcinoma with DCIS grade 3 was diagnosed in the vulvar excision. Mammography detected no breast carcinoma. The patient received aromatase inhibitor (Exemestane) for 5 years. Irradiation was given locally in the vulvar region (30 x 2 Gray) and regionally for both inguinal region (25 x 2 Gray). No recurrence 8 years after the vulvar operation. Results: Histopathological and immunohistochemical (IHC) examina- tion revealed an invasive adenocarcinoma with breast cancer features which was positive for GATA3, ER, PR, AR, CK7, MUC1, but negative for HER2, WT-1, TTF-1, GCDFP-15 and CK20. For differential diag- nosis the following alternatives were considered 1. metastasis/regional recurrence from endometrium adenocarcinoma, 2. breast cancer metas- tasis, 3. carcinoma arising from ectopic breast tissue, 4. carcinoma arising from local apocrine sweat glands. The histological findings together with the IHC results were mostly suggestive for a primary vulvar adenocarcinoma arising from anogenital mammary-like glands. Only tumour tissue was detected in the lesion without ectopic breast tissue or apocrine sweat glands (mucoapocrin marker GCDFP-15 was negative in the tumour). Conclusion: Vulvar adenocarcinoma of mammary gland type is a rare tumour arising from specialized anogenital mammary-like glands. Mammography excluded primary breast carcinoma. Dif- ferential diagnosis is challenging: 1. Absence of uroplakin II, but ER+, mammaglobin+ can confirm breast origin. 2.Metastatic breast carcinoma may mimic GATA3+ invasive urothelial carci- noma. 3.Metastatic lobular carcinoma may mimic plasmocytoid bladder carcinoma. The current case with DCIS component was suggestive of a primary carcinoma. Diagnosing a breast carcinoma like tumour outside the breast requires to “think outside the box”. E-PS-02-015 Pleomorphic adenoma-like tumour of the breast: an unusual entity A. Syrnioti*, E. Tolparidou, T. Koletsa *Department of Pathology, School of Medicine, Aristotle University of Thessaloniki, Greece Background & objectives: “Pleomorphic adenoma-like tumour of the breast” is a term that has been recently proposed to describe breast lesions with overlapping histopathologic features between pleomorphic adenomas (PAs) of the salivary glands (SGs) and matrix-producing metaplastic breast carcinomas (MBCs). Methods: Here we describe a case of a PA-like tumour of the breast, in an 87-year-old female, who presented with a 6-cm lump in the right breast, near the nipple. No lymphadenopathy was evi- dent. The patient underwent modified radical mastectomy. Hema- toxylin-eosin and immunohistochemical stained sections from the tumour were examined. Results: Microscopic examination revealed a well-circumscribed tumour, consisting of an epithelial component within myxoid or chondroid stroma with focal osseous metaplasia. The epithelial component was characterised by atypical tubular and cribriform structures, and scattered individual cells. Moderate atypia was focally detected, without significant mitotic activity. On immunohistochemical evaluation, neoplastic cells were positive for CK5/6, AE1/AE3, and S100, whereas immunostains for ER, PR, HER2, p53, and p63 were negative. Few cells were immunoreactive to SMA, GFAP, and CD117 antibodies. The Ki67 proliferative index was <5%. Taking into account the overall indolent histological features and the focal atypia, the diagnosis of PA-like tumour of the breast was set. The patient remains disease-free. Conclusion: PA-like tumour of the breast is an unusual entity with diagnostic challenges. There are no strict diagnostic criteria discriminating it from MBC. The majority of the cases have an indolent behaviour, although cases of local recurrence or carcinoma development have also been reported. Considering the rarity of this entity, multicentre studies are warranted to accurately determine its biological nature and behaviour, as well as the best therapeutic approach. S194