ECP 2023 Abstracts

S201 Virchows Archiv (2023) 483 (Suppl 1):S1–S391 13 the recent finding that GM is the first event occurring in the serrated carcinogenic pathway of colon carcinoma. E-PS-06-031 Digestive neuroendocrine tumours with hepatic metastasis: a single centre experience S. Gharbi*, D. Bacha, I. Mallek, E. Benammou, M. Mbarek, H. Mes- tiri, A. Lahmar, S. Ben Slama *Department of Pathology, Armand Trousseau Hospital-Sorbonne University, Tunisia Background & objectives: Patients with neuroendocrine neoplasms, develop hepatic metastases in 50-95 % of cases. Their diagnostic and therapeutic management represents a challenge, especially those with an aggressive fashion. Our study reports epidemiologic and clinico- pathological features of digestive neuroendocrine hepatic metastasis. Methods: It was a retrospective single-centre study. Cases were col- lected in the pathology department of the M. Slim Hospital over a period of 22 years (2000 to 2022). Clinicopathological data were col- lected from medical records of the surgery department of the same hospital. Tumour grades were evaluated according to the 2019 world health organization classification. Results: Thirty-one patients with DNHM were included. Their mean age was 58 years. The sex-ratio M/F was 2. Diagnosis was performed in hepatic biopsy in the majority of cases (76,3%) and in metastasectomy specimens in 23,7% of cases. Primitive site was small intestine (n = 8), pancreas (n = 7), colon (n =4 ), stomach (n = 1) and in 11 patients the primary site was unknown. The majority of cases was well differentiated (grade 1 in 12 cases, grade 2 in 9 cases and grade 3 in 6 cases). Poorly differenciated carcinoma: 4 cases. Mean tumour size: 45 mm (10-65mm). Conclusion: Although well differentiated, the rate of metatsates was high and there are cases with unknown primary site Complete imaging, clinical, and pathological studies can help to iden- tify the primary origin and to improve the patients’ management. E-PS-06-032 Granular cell tumour of the appendix with unusual morphologic features C. Girleanu*, B. Murphy, J. Larkin, G. Woods *St James’s Hospital Pathology Dept., Ireland Background & objectives: Granular cell tumour (GCT) is a rare soft tissue tumour which can occur in various sites throughout the body at any age. We present a case of a GCT of the appendix with unusually prominent fibrous stromal bands on histology. Methods: We described a 54-year-old male who presented with abdominal pain and bloating. A submucosal lesion at the appendiceal base was previously revealed on colonoscopy and not visualised on CT scan. A resection was performed, and the lesion was macroscopically and microscopically assessed with H&E, immunohistochemistry (IHC) and special stains being performed to reach the final diagnosis. Results: Macroscopically a well circumscribed submucosal lesion, 12mm in size was present at the base of the appendix. Microscopi- cally it was unencapsulated, consisting of prominent fibrous stromal bands dissecting nests of uniform cells with spindled nuclei, occasional nucleoli and abundant, eosinophilic granular cytoplasm, without sig- nificant pleomorphism, mitotic activity or necrosis. IHC and special stains showed that the lesion was positive for S100, Inhibin and CD34, with weak, non-specific positive staining for CD1a and EMA. DPAS highlighted cytoplasmic granules. The lesion was negative for Desmin, SMA (also negative within the fibrous bands), C-kit, DOG1, AE1/AE3, Melan A and HMB45. P53 showed wild type staining and Ki-67 was manually estimated as 1-2%. Conclusion: The features were of a benign GCT of the appendix. Clinical and endoscopic differential diagnoses included schwannoma, gastrointestinal stromal tumour (GIST), leiomyoma, inflammatory myofibroblastic tumour and also (based primarily on S100 positivity) metastatic melanoma and Langerhans cell histiocytosis, however, mor- phological features were not congruent with either of these. Our case highlights an unusual morphological feature that may be seen in GCT and the importance of including them within the differential diagnosis of submucosal lesions arising in the gastrointestinal tract. E-PS-06-033 A descriptive case series of 11 patients diagnosed with Whipple’s disease M. Gómez Tena*, J. Martínez, J. Rodriguez Pous, A. Domingo Rubio, I. BLAZQUEZ, A. De Carvalho Ovalles, E. Quirós Arape, M.J. Paules Villar *Hospital Universitari de Bellvitge, Spain Background & objectives: Whipple´s Disease (WD) is a rare infec- tious systemic illness. Its low incidence and lack of specific symptoma- tology makes WD a challenging and often delayed diagnosis. Before the introduction of PCR-based methods, the gold standard was histo- logical detection of PAS-positive macrophages. Methods: A 15-year retrospective analysis (2007-2022) identified 11 patients diagnosed with WD at our institution. We review their clinical and histological features. Results: The mean age at diagnosis was 63 years with 7 (64%) of the patients being males. 8 had classic WD, 2 localized WD (endo- carditis) and 1 isolated neurological WD. We received 21 biopsies: 14 were from duodenum, 2 from lymph node, 1 from brain, 1 from stomach, 2 from heart and 1 from subcutaneous tissue. PAS + mac- rophages were present in 17 samples. T. whipplei PCR was positive in 15 of 17 samples: 12 duodenal biopsies (3 with normal histology), 1 gastric biopsy, 1 endocardial biopsy and 1 brain biopsy. Two patients were diagnostic for both WD and another disease: secondary amyloi- dosis and H. pylori chronic gastritis. Conclusion: The diagnosis of WD is based on the existence of clinical signs and symptoms compatible with the disease and in the presence of PAS+ macrophages. However, when the histologic findings are not suggestive of WD, T. whipplei PCR is a useful tool for its diagnosis. E-PS-06-034 Double opportunistic infectious duodenitis on a immunodeficiency syndrome background: is it primary or secondary? A. Gont*, G. Becheanu, A. Haidar *University Emergency Hospital Bucharest, Poundbury Cancer Insti- tute, Romania Background & objectives: Primary or acquired immunodeficiency shows a quiescent histological impact on the gastro-intestinal mucosa. Nevertheless, it has an unexpected potential for diagnosis which leads to the proper treatment for these patients. Methods: In the Department of Pathology from “Victor Babe ș ” Insti- tute, we received for a second opinion one paraffin block containing three duodenal biopsies collected during a superior endoscopy of a patient. Following the examination of the conventional stained slides, special stains (Giemsa) and IHC studies for CMV have also been per- formed to confirm the diagnostic. Results: We present the case of a 66-year-old female admitted to the Emergency Department in a critical, life-threatening condition and extremely malnourished (body mass index <18kg/m2). The attending physicians have excluded any malignancy or common infection and consideration has been given to an autoimmune aetiology. On the edge