ECP 2022 Abstract Book

Virchows Archiv (2022) 481 (Suppl 1):S1–S364 13 obtained indicate that specimen radiography provides perfect docu- mentation of the residual breast cancer. E-PS-02-009 The rare and the hidden – twin challenges posed by malignancy in microglandular adenosis of the breast. Metaplastic matrix producing triple negative and multifocal luminal type invasive carcinomas S. Di Palma*, A. Gamage, A. Stacey-Clear, J. Horsnell, I. Ellis *Royal Surrey County Hospital, United Kingdom Background & objectives: Triple negative metaplastic carcinoma(TNMC) and luminal type invasive duct al carcinoma(LTIDC) arising in microglandular adenosis(MGA) emphasized the spectrum of malignancy developing from MGA is wider. Management and prognosis of these malignancies are different from TNMC and IDC not arising from MGA. Methods: Here we report on two cases of invasive malignancy arising from MGA. Neither of them could be recognized from the pre-operative core biopsy. This report discusses the results of the retrospective analysis of the previous core biopsies, it reviews the literature for similar cases and considers the implications of this rare tumour type on patient management. Results: One case, core biopsy reported as B4, suspicious of malignancy. As a result diagnostic surgical excision was performed instead of WLE and SLN biopsy. Following diagnosis of triple negative matrix producing metaplastic carcinoma arising in a background of MGA, WLE and SLN biopsy was recommended but the patient opted for a mastectomy which showed residual foci of MGA with atypia and no lymph node metastasis on SLN biopsy. The other patient had a core biopsy of LTIDC(ER & PR were 8/8 and Her2 were negative), B5b without suggestions of background MGA. Subsequent WLE specimen revealed multifocal LTIDC. The background MGA was only recognized after specialist review of the case. Conclusion: Despite the rarity of MGA, we have recently encoun- tered two cases where the histological subtyping were not typical. In one instance the complicating invasive carcinoma was triple negative but had a matrix producing metaplastic carcinoma com- ponent. In the other instance luminal type and multifocal IDC. Our examples suggest that: MGA is usually not recognized on core biopsy and MGA can be associated with metaplastic carcinoma as well as luminal NST IDC. E-PS-02-010 Extramammary metastases to the breast: a retrospective analysis of 15 cases in a Tunisian institution I. Saguem*, C. Kammoun, O. Boudawara, M. Manai, C. Chaari, W. Ghribi, N. Gouiaa, T. Boudawara, S. Makni *Department of Pathology, Habib Bourguiba University Hospital, Sfax, Tunisia Background & objectives: Extramammary metastases to the breast (EMMB) are uncommon. Distinguishing these tumours from primary breast cancer is crucial as it affects clinical management and treatment. The aim of this work is to review clinico-pathological and therapeutic features of this rare entity. Methods: In a retrospective study, we collected 15 patients who were diagnosed, in our department of pathology, with EMMB between 1992 and 2020 (29 years). These tumours represented 0.25% of the total number of breast cancer cases during the period of study (5892 cases). An analysis of clinical, imaging, pathologi- cal and therapeutic features was carried out in all cases. Results: The mean age of our patients (1 male-14 females) was 38.42 years (13-62 years). All patients presented with a mammary mass which was more frequently unilateral, left-sided and located in the superolateral quadrant of the breast. Metastases were synchronous with primary tumours in 9 cases and metachronous in 6 cases (average onset time: 44.4 months). Sources of EMMB were carcinomas of the lung, ovary, stomach (each 2cases), nasopharynx and rectum (each 1case). Other sources were lymphoma (3cases), melanoma, neuroblastoma, leiomyosarcoma and choriocarcinoma (each 1case). Immunohistochemistry was used in 12 cases. Therapeutic management was based on chemotherapy or radio- chemotherapy. Six of our patients were dead (average delay of 12.83 months). Conclusion: The diagnosis of metastasis in the breast of extra- mammary origin is often difficult. A confrontation of clinical and pathological data with immunohistochemical study is recom- mended. Immunohistochemistry is very helpful in the absence of medical history. The most common sources are lymphomas and melanomas. In this study, there was a high incidence of carcino- mas. The prognosis of this entity is poor. The death rate is about 80% during the first year following the discovery of the breast metastasis. E-PS-02-012 Metastatic NET of the cranial orbit: a case report of unknown origin I. Nitsios, G. Theodoropoulou, A. Dimitriadi, C. Roumbas, C. Karantzias, N. Poulianitis*, A. Kostopoulou, X. Grammatoglou, N. Georgakoulias, T. Choreftaki *Department of Pathology, "G. Gennimatas" General Hospital, Athens, Greece Background & objectives: Metastatic neoplasms of unknown primary location often present difficulty in diagnosis. The intracranial spread of tumours is a common site and clinical findings can point to the origin of the neoplasm. Methods: A 50-year-old female presented with right exophthalmos, complete vision loss and ocular pain. Cerebral MRI showed a right cranial orbit mass, with intracranial extension, most likely consist- ent of meningioma or a metastasis. Further findings discovered, a previously unknown breast lesion with invasive characteristics. Representative sections of the orbital mass were examined under H&E and immunohistochemical stains. Results: Microscopic examination demonstrated a tumour of epithelioid differentiation (AE1/AE3 positive), predominantly insular and nested pattern of growth (almost 100%). Neoplas- tic cells display eosinophilic, granular cytoplasm with a bland eccentric placed nuclei and were diffusely positive for oestrogen and progesterone receptors, E-cadherin, GATA3, Synaptophysin and Chromogranin A. Common mammary markers such as CK7, EMA, GCDFP-15, ERBB2 (HER2) and Mammaglobin, were neg- ative along with S100 and transcription factors such as CDX-2 and TTF-1. Cell Proliferation index Ki67 (MiB-1) was estimated at 25%. Taking all the above histologic and imaging findings into consideration, a diagnosis of metastatic NET G2 most likely of breast origin was made. Conclusion: Breast NETs are extremely rare neoplasms (<1% of primary breast neoplasms), by definition are invasive tumours and may present with a metastasis. Due to the rarity of these neoplasms, diagnosis of metastasis is possible through exclusion and consid- eration of clinical findings. Further studying of these tumours may S193