ECP 2023 Abstracts

S159 Virchows Archiv (2023) 483 (Suppl 1):S1–S391 13 features. Serial sections were applied to SLN biopsy; one was stained with AE1/AE3 while others were stained with H&E. On microscopic examination, small glands lined by monolayer of cuboidal/columnar epithelial cells were detected within the capsule and focally in the lymph node parenchyma. No atypical appearance was seen in these cells. The immunoprofile of these cells showed positive staining for AE1/AE3, Oestrogen Receptor, Pax8, and negative staining for Gata3. Morphological findings with supporting immunohistochemical results confirmed the diagnosis of benign Müllerian inclusion of SLN. Conclusion: Benign Müllerian inclusions are most commonly seen in pelvic and para-aortic lymph nodes. Axillary lymph node involvement is extremely rare. It should be kept in mind their glandular appearance may be confused with metastasis in patients with breast carcinoma. Their histomorphological patterns and immunoprofile assist to distin- guish from metastatic lesions. Especially on a small biopsy specimen and frozen sections, being aware of this entity has paramount impor- tance during differential diagnosis and to avoid misclassification. E-PS-02-025 Male breast carcinoma in a symptomatic breast unit, a ten year retrospective review R. Farrell*, A. O’Shea, M. Staunton *Department of Histopathology, Beaumont Hospital, Dublin, Ireland Background & objectives: Male breast cancer is rare, representing 1% of all breast cancers diagnosed in Ireland between 1995 – 2019. We evaluated the histopathology of male breast specimens received from a busy symptomatic breast service. Methods: Using our laboratory information system we retrospectively reviewed all pathology reports produced by our laboratory recorded as SNOMED T04000 breast and classified as gender: male between 01/01/2013 and 31/12/2022. The data was then corrected to remove gender misclassifications and unique patient identifiers were removed. Statistical analysis was performed with Graphpad prism version 7.0.0. Results: We identified 192 specimens from 151 male patients, of these 44.2% (85) were small biopsies, 38% (73) benign excisions, and 15.6% (30) malignant resections. Of the 28 primary invasive breast cancers, 24 were resected. The 6 other resections were for: ductal carcinoma in situ (DCIS) (1), skin malignancies (2), and soft tissue sarcomas (3). Primary invasive breast cancers were invasive ductal carcinoma (IDC), no special type (23); IDC, papillary subtype (4), and invasive lobular carcinoma (1). All breast cancers were oestrogen receptor positive, 6 were HER2 positive. Concomitant DCIS was present in 12 cases. Tumour grade was stratified grade 1 (6), grade 2 (14), and grade 3 (8). Conclusion: We illustrate the relative rarity of male breast cancer with on average fewer than 3 cases per year, which limits statistical inter- pretation. However, papillary carcinomas were seen more commonly (14.2%) among male patients than would be expected in female patients (0.5%), and invasive lobular carcinomas were rare (3%). The low num- ber of specimens and prevalence of rarer cancer subtypes illustrates the need for further research in male breast disease. E-PS-02-026 Computer-aided quantitative analysis as second opinion in the assessment of low HER2 IHC score in breast cancer – a pilot evaluation Y. Glickman*, S. Zilber, Y. Arbel, Y. Sufrin, B. Benbenishti, Y. Sherman *Applied Spectral Imaging, Israel Background & objectives: The adoption of computer-aided quantita- tive assessment for the differentiation between negative and equivocal HER2 scores in breast cancer is increasing. This pilot evaluation aims at assessing the usefulness of computerized quantification as second opinion in diagnosis of low HER2 . Methods: 19 core biopsy specimens from 14 patients were included. Two slides from each core were stained with H&E and HER2. Slides were examined by certified pathologists using conventional microscopy and digitalized images obtained on the Hamamatsu NanoZoomer S360 and reviewed on the SECTRA viewer. The specimens were further analysed using Applied Spectral Imaging’s FDA-cleared HER2 quan- titative scoring. Results: Among the 14 patients included in this study, 10 had IDC, 3 ILC and one mucinous carcinoma. Following manual HER2 analy- sis, 8 slides were scored (0), 5 slides (1+), 3 slides (2+) and 3 slides (3+). These manual results were compared to the computerized scores obtained with the HER2 quantitative biomarker. Concordance was found in 14 out of 19 slides (11 patients). 5 slides (3 patients) were manually reported as HER2 negative (0) or (1+) while the computer- ized system yielded positive (2+) scoring. A second manual review of these inconsistent results was recommended in order to further confirm the diagnosis. Conclusion: This evaluation exemplifies the potential usefulness of computer-aided scoring as a second opinion for HER2 slide assess- ment, especially in cases of HER2 low. This further illustrates the pos- sible use of combined manual reading and computerized analysis as a mean to increase standardization and diagnostic confidence when reporting HER2 immunohistochemistry in breast cancer patients. E-PS-02-027 Incidence of atypical lesions in routine breast reductions war- rants assessment of the feasibility of orientation and inking each specimen T. Gul*, M. Leader *St James’s Hospital, Ireland Background & objectives: To assess the feasibility of orientation and inking of breast reduction specimens. Methods: 200 cases of BRS’s were analysed retrospectively for sig- nificant pathology. The age ranged from 19-84 years with a median age of 41 years. Four sections were sampled from each breast specimen. Orientation and inking of specimens were instituted after the results of our audit. Results: Five of 200 cases (2.5%) showed a significant abnormality including 1 with atypical ductal hyperplasia, 3 with atypical lobular hyperplasia and 1 with high grade multifocal DCIS with cancerization of lobules over a span 0f 20 mms. The latter patient’s specimen was not orientated or inked and prompted the use of inking in future specimens to assist patient management. Conclusion: This study found that the procedure of orientation and inking was simple and easily performed. We recommend this should be included in guidelines to benefit further sampling, exact localization of the lesion and its excision status and patient management. E-PS-02-028 Rare presentation of medullary thyroid carcinoma with bilateral breast metastasis: a case report E. Gun*, O. Layth Qassid *Basildon University Hospital, Mid and South Essex NHS Foundation Trust, Basildon, Essex, United Kingdom Background & objectives: Medullary thyroid carcinoma (MTC) is an uncommon type of thyroid cancer that comprises only 3-5% of all thyroid cancers. We aimed to present a case with bilateral breast metas- tasis of MTC. Methods: A 48-year-old female presented with a lump in her left breast. Ultrasonography revealed a 10x7 mm mobile lump in the lower outer quadrant of the left breast. Tru-cut biopsy of the lesion revealed nests and cords of tumour cells with pink amorphous material in between. The tumour was negative for ER, PR, and HER2.