ECP 2023 Abstracts

S170 Virchows Archiv (2023) 483 (Suppl 1):S1–S391 13 greatest variation by category between pathologists was statistically significantly difference in category 2 (p < 0.001). Conclusion: Intra-laboratory Ki67 reproducibility was high. The great- est deviation was detected in the clinically significant "grey zone". The International Ki67 in Breast Cancer Working Group (IKWG) consensus is that Ki67 5% or less, or 30% or more are valid, while values 5–30% are not recommended for use in making decision about chemotherapy. The authors feel it advisable to conduct training on in-laboratory ana- lytical validation using telemedicine platforms. Training of the visual calculations for Ki67 will improve reproducibility and accuracy. E-PS-02-069 Adenoid cystic carcinoma of the breast: a case report special triple- negative cancer subtypes I. Telezhnikova*, G. Setdikova *Loginov Moscow Clinical Research Center, Russia Background & objectives: Adenoid cystic carcinoma (ACC) of the breast is rare, accounting for less than 0.1% of all breast cancers. Unlike counterpart in the salivary gland, ACC of the breast is associated with an excellent prognosis paradoxical to its unfavourable, triple-negative profile. Methods: We present the case of a 55-year-old woman presenting with a left breast mass identified by mammographic screening was examined at our centre. Breast ultrasound revealed a sharply marginated, hypo- echoic mass. 12 × 0.8 × 11.2 mm in size in the upper outer quadrant, and a core needle biopsy was performed at the mass site. Results: The preoperative diagnosis was stage I (cT1N0M0) triple- negative breast cancer. Surgery consisted of breast segmental resec- tion with axillary contents. Pathological examination of the excised specimen revealed a so-called adenoid cystic pattern without high- grade transformation. Note, the tumour had basaloid component rang- ing 10%. Immunohistochemical staining results were negative for ER, PR, HER2, were also negative for AR. The atypical epithelial cells were strongly positive for CK7, and the atypical myoepithelial cells were strongly positive for CK5/6, p63 and SMA. Ki67 labelling index was heterogeneous and focal areas elevate (25%). 12 lymph nodes were found without metastases. The patient received one course of adjuvant chemotherapy. The 3-year recurrence-free survival rate was observed. Conclusion: Despite the triple-negative phenotype, the classic subtype ACC usually shows favourable behaviour. Regional and distant metas- tases are rare, and radical surgical excision is usually curative. We must search for high-grade transformation and basaloid component thorough sampling is crucial. Lymph node involvement was not present in our case. Knowing that this cancer usually presents as localized disease, can help clinicians plan the operative management of these tumours. More effective therapies for patients with special types of breast cancer require tailored treatment. E-PS-02-070 The risk of metachronous cancers in breast cancer patients. Pres- entation of three rare case reports H. Trihia*, G. Stanc, E. Souka, G. Galanopoulos, C. Valavanis, G. Vorgias *Pathology Department Metaxa Cancer Hospital, Greece Background & objectives: Breast cancer patients have an increased risk of developing second primaries. The risk is associated with hormo- nal therapy. Independent primary malignancies in the breast and cervix is a rare entity. Women with BRCA1/2-mutations have an increased risk of ovarian high-grade-serous-carcinoma. Methods: Three postmenopausal women of 59, 69 and 56 years of age, were diagnosed with luminal A/B type, breast ductal carcinomas, grade II/II/III, received tamoxifen treatment postoperatively and sub- sequently developed a uterine low grade endometrial stromal sarcoma (LGESS), adenoid cystic carcinoma of the cervix and ovarian high grade serous carcinoma (HGSC) with SET features, after 12, 11 and 3 years, correspondingly. Results: A 73-year-old woman with a history of breast cancer at 59, under- went vaginal hysterectomy, due to prolapse, where she was incidentally diagnosed with an intramural 3cm uterine tumour with histologic features of LGESS. An 80-year-old woman was diagnosed with adenoid cystic car- cinoma of the cervix, after vaginal bleeding. At the age of 69, she was diagnosed with grade III, luminal B, NOS breast carcinoma. A 61-year-old woman underwent a robotic salpingo-oophorectomy of a 5,5cm ovarian mass, diagnosed as HGSC with SET features. Although there was a history of luminal A breast cancer at 56, there was not a high index of suspicion before surgery. All women have received tamoxifen treatment. Conclusion: Women diagnosed and treated for breast cancer need to be followed up for metachronous gynaecological cancers. Uterine carcinomas and rarely sarcomas are associated with short- or long-term use of tamox- ifen. The occurrence of independent primary malignancy in the breast and uterine cervix is a rare event. Metachronous adenoid cystic carcinoma has not been described before. Breast cancers in BRCA-2-mutation carriers are similar to sporadic luminal-type tumours. Cancers arising in the ovary are almost exclusively of a HGS-histotype with SET features. E-PS-02-071 Youngest case of unusual type of carcinoma of breast in a 3 year old girl S. Vidhale*, V. Konsam, A. Lukram, F. Ahmed, H. Thanky, N. OZA, S. Kane *Histopia Lab, India Background & objectives: Secretory breast carcinoma (SBC) is a rare breast cancer found in both children and adults. Although SBC usually carries a favourable prognosis, there have been reported cases of metastases. Surgery is the primary mode of management of SBC. Methods: We report a case of a 3-year-old girl with a unilateral right breast lump suspected on Fine Needle Aspiration Cytology (FNAC) as papillary neoplasm and confirmed as primary SBC on histopathology and molecular studies. Results: Child presented with a single retroareolar lump measuring 0.5x0.5cm, non-tender and freely mobile. FNAC smears revealed sheets and papillae of epithelial cells with extensive apocrine metaplasia. His- topathological and biomarker studies of the excision specimen revealed tumour positivity for Mammaglobin, S100, CK7, Vimentin; while negative for P63,GCDFP-15, SOX10. Molecular analysis revealed the presence of ETV6-NTRK3 fusion. Patient was reviewed at a multidis- ciplinary treatment planning conference, underwent lumpectomy with nodal biopsy, and ongoing long-term postoperative follow-up. Conclusion: Considering the rarity, we report this case of secretory breast carcinoma in a three-year-old child (youngest to be reported in literature). Awareness of the cytomorphologic features and a high index of suspicion is necessary to order the right IHC panel for confirmation. E-PS-02-072 Cytoplasmic aggregation of RPB1 predicts failure of neoadjuvant chemotherapy against invasive carcinoma of no special type A. Voros*, B. Nagy-Miko, O. Olah-Nemeth, T. Pankotai, Z. Ujfaludy, A. Nikolenyi, G. Lazar, K. Ormandi, Z. Villanyi *University of Szeged, Hungary Background & objectives: Neoadjuvant chemotherapy is a common approach in treating breast cancer. We investigated cytoplasmic aggregation of the large subunit of RNA polymerase II, RPB1 in biopsy samples taken from invasive carcinoma of no special type before chemotherapy. Methods: Core biopsy samples were selected from patients candidating for neoadjuvant chemotherapy. Immunohistochemistry was performed to detect intracytoplasmic aggregation of RPB1 protein. For the evaluation immunofluorescent microscopy was used. Regarding tumour regression complete, partial and non-regressive pheno- types can be distinguished. To find possible connection between RPB1 aggregation and tumour regression, statistical analysis was performed.