ECP 2022 Abstract Book

Virchows Archiv (2022) 481 (Suppl 1):S1–S364 13 E-PS-02-016 Primary malignant melanoma of the breast. A rare case report M. Mnikhovich, A. Romanov*, D. Pastukhova, T. Sotnikova *Central pathology laboratory, Research Institute of Human Mor- phology, Russia Background & objectives: Primary melanoma of the breast is clas- sificated into cutaneous and non-cutaneous forms. Despite the fact that both forms of the tumour arise from melanocytes, they differ sig- nificantly. In the breast, non-cutaneous melanomas are extremely rare (<5% of all malignant melanomas) Methods: We present a case of primary non-cutaneous melanoma of the breast. A 60-year-old woman was admitted with complaints of a slowly growing pain-less mass in the left breast. A needle biopsy was performed (according to the results of which melanoma was suspected), followed by a total mastectomy with lymph node dissection and a wide histological (hematoxylin/eosin stain) and IHC study. Results: Gross examination showed multiple round whitish nodules in the breast parenchyma with extension into the mammary fatty tissue. Histological examination revealed many atypical spindle and round melanocytes against the background of desmoplastic stroma. Tumour cells expressed S-100, Sox-10, HMB-45, Melan A. There was a complete absence of expression of Her-2, ER, PR. A diagno- sis of primary non-cutaneous parenchymal melanoma of the breast was established. Conclusion: Primary non-cutaneous breast melanoma is rare and presents a diagnostic challenge for both the histopathologist and the clinician. Thanks to the presented case, we have expanded our understanding of the nature of these tumours. E-PS-02-017 Pure signet-ring cell carcinoma of the breast – two case reports of a rare entity T.M. Costa*, R. Sampaio *Centro Hospitalar Lisboa Ocidental, Portugal Background & objectives: Primary signet-ring cell carcinoma (PSRCC) of the breast is a very rare entity. To date, few cases have been reported in the literature. We present two case reports of pure PSRCC of the breast and discuss the available literature. Methods: We searched the archives of the Department of Sur- gical Pathology, Centro Hospitalar Lisboa Ocidental (CHLO), between 2010 and 2021. From the breast invasive carcinomas diagnosed in that period, we retrieved the pure PSRCC from the database. Clinical information was collected from the medical records, and the pathological material was reviewed according to the current WHO guidelines. Results: Of the total of 576 cases of invasive carcinoma diagnosed in surgical specimen only 2 cases showed dominant signet-ring cells (in at least 90% of the tumour) and were diagnosed as pure PSRCC. The age of the patients was 30 and 74 years-old. One of the cases was of histologic grade 2 and the other grade 3. Neither of the cases had axillary lymph node (LN) metastasis nor distant metastasis were present. One of the cases had family history of breast carcinoma. Both patients underwent adjuvant chemotherapy, radiotherapy and hormonal treatment. Conclusion: Pure PSRCC of the breast is uncommon and rarely mentioned in the English literature. It has been associated with an aggressive clinical course, with greater frequency of LN involve- ment, poorer prognosis and higher mortality rate, compared with other forms of breast cancer. Because of its rarity, there is no clear understanding of the oncogenesis, treatment and clinical follow- up of these patients. Once there are no established treatment guidelines we believe that sharing is important for better compre- hension of this entity. E-PS-02-018 To explore the changes of 21 gene detection in the 2022 ver- sion of the breast cancer NCCN guidelines and the interpreta- tion of the 21 gene in breast cancer in the 2017 version of the guidelines Y. Jia, S. Li, Y. Liu* *The fourth hospital, China Background & objectives: To compare the changes of 21 gene detec- tion in the 2022 version of the breast cancer NCCN guidelines and the 2017 version of the breast cancer 21 gene interpretation. Methods: The invasive breast cancer was screened, with negative lymph nodes/1-3 ipsilateral axillary lymph nodes, HER-2 nega- tive and infiltrating. The clinicopathological data of 207 patients with foci >0.5cm were collected. To study the differences in the 21 gene detection guidelines of the 2022 version of the NCCN Guidelines, compare the clinical significance of the two versions of the guidelines. Results: A total of 207 IBC patients were collected, including 1 male and 206 females, aged 35-71 years. Interpretation results of the 2017 edition: 124 patients with low recurrence risk, 70 patients with moderate recurrence risk, and 13 patients with high recur- rence risk. Interpretation results of the updated guidelines: 92 patients with low risk of recurrence, 95 patients with moderate risk of recurrence, and 20 patients with high risk of recurrence. There were significant differences in the interpretation results of the two versions of the guidelines (P<0.05). Conclusion: The updated 2022 version of breast cancer NCCN guidelines 21 gene detection can effectively distinguish the RS interpretation results of breast cancer patients before and after menopause in clinical practice. For patients with early-stage invasive breast cancer, accurate determination of 21-gene status is critical to ensuring that patients most likely to benefit receive targeted therapy. E-PS-02-019 Association between protein expression of KISS1 and KISS1R and receptor status in invasive breast carcinoma S. Bachurska*, D. Pupaki *KOC Plovdiv, Bulgaria Background & objectives: KISS1 and KISS1R act as metastasis suppressors, in breast cancer their function is altered with the exact mechanism being still unknown. Here we present the association between protein expression of KISS1 and KISS1R with receptor status in invasive breast carcinomas. Methods: Immunohistochemistry was used to detect protein expression of KISS1, KISS1R, ER, PR and HER2. The Allred scoring system was used for ER and RP and a four-tier scoring system was used for HER2. KISS1 and KISS1R immunostaining was assessed using ImageJ software by measuring mean grey value and calculating reciprocal intensity that is directly proportional to the amount of chromogen. Results: A total of 54 cases of invasive ductal carcinomas were examined. For ER and PR scores of 0-2 were considered recep- tor-negative and scores of 3-8 were considered receptor-positive. For HER2, scores of 0 and 1+ were considered HER2-negative and scores of 3+ were considered HER2-positive. Equivocal scores of 2+ were resolved by DISH. Examined cases included 12 S195