ECP 2023 Abstracts

S207 Virchows Archiv (2023) 483 (Suppl 1):S1–S391 13 group is due to the patient’s comorbidities. This study showed that proliferation index of Ki67 is directly proportional to the prognosis. An increase of 0.07 units in Ki67 increased the risk of death by 2.8%. Conclusion: In this case series study, we wanted to emphasize the impor- tance of parameters such as gender, risk assessment, size, localization, and proliferation index on prognosis in gastrointestinal stromal tumours. Funding: Cukurova University E-PS-06-056 Lymphomas with primary gastrointestinal presentation: 5 years’ experience in a quaternary care centre in Southern India A. Lakshmanan*, D. Maria George, A. Subramanyam *Apollo Hospitals, India Background & objectives: Lymphomas can involve the Gastrointes- tinal tract (GIT) either as the sole area of disease (primary) or as a secondary spread of systemic disease. GIT is the commonest site of extra nodal presentation of non-Hodgkin lymphoma (NHL). Methods: A retrospective study from 2018 to 2022 was conducted wherein all cases of lymphoma with primary gastrointestinal presen- tation were retrieved. Haematoxylin and eosin-stained sections and immunostains done on all the cases were retrieved and reviewed. Results: A total of 156 cases of lymphomas were diagnosed in GIT specimens. Stomach (n=81) was the commonest site followed by small intestine (n=40), large intestine (n=33) and oesophagus (n=2). B-cell NHLs were noted in 148 cases of which Diffuse large B cell lymphoma (DLBCL) was the commonest (102 cases) followed by high grade B cell lymphoma (14 cases), low grade marginal zone lymphoma of mucosa associated lymphoid tissue (11 cases), mantle cell lymphoma (7 cases), follicular lymphoma (4 cases) and Epstein Barr virus positive DLBCL (3 cases). 8 cases of T-cell lymphomas were noted including some rare entities. Three cases of Hodgkin lymphomas with secondary involvement of GIT were noted. Conclusion: The distribution and incidence of various entities in our study was comparable to other Indian studies as well as few western studies. Gastrointestinal lymphomas are heterogenous with different treatment modalities. Hence, diagnosing them correctly would help in appropriate treatment. E-PS-06-057 The prognostic value of the co-expression of Programmed Death- Ligand 1 (PD-L1) and Ki-67 in colorectal cancer: insights from a northern Portuguese patient cohort N. Lamas*, I. Havenko, F. Sousa, S. Martins *Life and Health Sciences Research Institute (ICVS), School of Medi- cine, University of Minho, Braga, Portugal; Anatomic Pathology Ser- vice, Pathology Department, Centro Hospitalar Universitário de Santo António (CHUdSA), Porto, Portugal Background & objectives: Colorectal Cancer (CRC) represents a major health problem worldwide and the development of novel prognostic tools might lead to better-quality patient treatment. The co-expression PD-L1|Ki-67 has shown promising prognostic value in certain tumours, but its role in CRC is unknown. Methods: We conducted a retrospective, observational and descriptive study involving patients with CRC undergoing curative surgery at the Hospital de Braga, Portugal, from January 1st 2005 until January 1st 2010. Tissue microarrays constructed from the primary CRC patient specimens were used to evaluate the PD-L1|Ki-67 co-expression using immunohistochemistry. The PD-L1| Ki-67 co-expression levels were then correlated with various clinical-pathological parameters. Results: Positive co-expression of both PD-L1 and Ki-67 was observed in 35,4% of patients with CRC. PD-L1|Ki-67 co-expression was signifi- cantly associated with age at diagnosis, histological type of CRC and tumour recurrence. Positive co-expression was higher in patients without disease recurrence (44,6%) compared to those with recurrence (22,7%). A statistically significant association of marker co-expression with patient prognosis was not possible to establish, although a longer survival time was observed in patients without expression of both PD-L1 and Ki-67. Conclusion: We demonstrated a significant association of PD-L1|Ki-67 co-expression with age at diagnosis, histological type and CRC recur- rence. The double positive co-expression seems to represent a protec- tive effect in patients without CRC recurrence. However, we could not establish a statistically significant association between PD-L1|Ki-67 co-expression with the prognosis of CRC patients. Further studies involving a larger set of patients across multiple centres worldwide may help to further clarify the relevance of PD-L1|Ki-67 co-expression in determining the prognosis of patients with CRC. E-PS-06-058 AMACR – a marker to differentiate between primary jejunal and metastatic adenocarcinoma A. Georgescu*, M. Sajin, T. Georgescu *Department of Pathology, "Carol Davila" University of Medicine and Pharmacy Bucharest, Department of Pathology, Nephrology Clinical Hospital "Dr. Carol Davila", Bucharest, Romania Background & objectives: AMACR is a marker expressed in prostatic adenocarcinoma, papillary renal cell carcinoma and ovarian clear cell carcinoma. Additionally, AMACR has been discovered to be expressed in around 81.7% of all colorectal adenocarcinomas, especially those located on the left colon. Methods: We collected clinical, epidemiologic and pathological data regarding 10 cases of colorectal adenocarcinomas, 2 primary jejunal adenocarcinoma and one jejunal metastasis of metastasis in a patient with a known history of colon adenocarcinoma. All the cases have been stained for AMACR, CK7 and Mismatch Repair Proteins. The collected data has been analysed with SPSS software. Results: Mean age of the patients was 58 years, males represented 69,2% of all cases and 61% came from a rural environment. Immuno- reactivity for CK7 was observed in 100% of jejunal adenocarcinoma, 10% of colorectal adenocarcinoma (patchy) and it was not present in the jejunal metastasis. AMACR was however expressed in 90% of all colorectal adenocarcinomas, in none of the jejunal adenocarcinomas and it was present in the jejunal metastasis. Loss of expression for MLH1 and PMS2 was observed in 10% of all colorectal adenocarci- noma and loss of MLH1, PMS2, MSH6 and MSH2 was observed in another 10%. No correlation was observed between the loss of MMR proteins and AMACR immunoreactivity. Conclusion: In conclusion, the combination of AMACR and CK7 can help distinguish between a primary small intestinal adenocarci- noma and a colorectal adenocarcinoma metastasis to the jejunum. The distinction between the two entities is essential, as it alters the TNM of the tumour and, subsequently, the future neoadjuvant therapy. There was no correlation observed between the immunoreactivity for AMACR and the presence of microsatellite instability. More studies, performed on a larger number of cases, are needed in order to validate this observation. E-PS-06-059 Anal hidradenoma papilliferum, unexpected finding in haemor- rhoidectomy. Case report R.D.P. Lopez-Panqueva*, D. Ellmer, M. Rolon Cadena, J. Padron *Fundación Santa Fe de Bogotá, Department of Pathology and Labora- tory Medicine, Universidad de Los Andes, Bogotá, Colombia Background & objectives: Hidradenoma papilliferum, an extremely rare benign neoplasm in the anal region, is typically associated with the vulva. We report an incidental case from a haemorrhoidectomy, contributing to the scant literature on this topic.