ECP 2022 Abstract Book

Virchows Archiv (2022) 481 (Suppl 1):S1–S364 13 E-PS-06-040 Mixed neuroendocrine-non-neuroendocrine neoplasm of the ampulla of Vater: a case report I. Saguem*, M. Manai, M. Mellouli, S. Ben Tekaya, S. Graja, A. Trigui, T. Boudawara, R. Kallel *Department of Pathology, Habib Bourguiba University Hospital, Sfax, Tunisia Background & objectives: Mixed neuroendocrine-non-neuroendocrine neoplasm (MiNEN) of the ampulla is extremely rare, with only 20 cases reported in the literature. The aim of this observation is to report a case of MiNEN in the ampulla and study its clinicopathological features. Methods: A 62-year-old woman presented with jaundice. The CT scan and MRI revealed an ampullary mass with a highly vascular- ised pattern, and dilatation of both the common bile duct and the main pancreatic duct. Endoscopic ultrasound found a solid tumour at the ampulla, infiltrating the duodenal muscle layer. A biopsy was performed and concluded to ampullary adenocarcinoma. The patient underwent pancreaticoduodenectomy. Results: The surgical specimen showed a tumour measuring 20×18 mm on the ampulla. Histologically, this tumour was composed of two different components: the first component consisted of a well-differ- entiated adenocarcinoma (50% of the tumour). The second component was formed by intermediate-to-large-sized neoplastic cells showing solid-nest growth. These cells presented a high degree of cytologic atypia with prominent nucleoli. The mitotic rate was evaluated at 12/10HPF. Immunohistochemical analysis demonstrated that the lat- ter component was positive for synaptophysin and chromogranin-A. The cells had a Ki-67 index higher than 20%. This component was diagnosed as large-cell neuroendocrine carcinoma. The diagnosis of MiNEN of the ampulla was retained. Conclusion: The diagnosis of MiNEN constitutes a real challenge, because of the absence of typical clinical symptoms or imaging findings. Histologically, the presence of two components with neuroendocrine and non-neuroendocrine features is needed. Thorough sampling of the specimen is necessary for detection of these two components. The confirmation of the diagnosis is based on immunohistochemical staining. The main treatment is radical surgical resection. Further research are mandatory to establish the best method of diagnosis and treatment of these tumours. E-PS-06-041 Dedifferentiated liposarcoma of the cecum and right adrenal gland, leiomyosarcoma phenotype H. Imada*, T. Tashima, K. Deguchi, T. Fujii, Y. Hirano, Y. Yazawa, T. Torigoe, J. Ichikawa, C. Muramatsu, S. Kanno, T. Kawasaki *Saitama Medical University, Japan Background & objectives: The patient, a 59-year-old Japanese woman, presented with a palpable mass in the upper, inner portion of the right breast. Ultrasound-guided, core needle biopsy of the breast lesion was performed, yielding a histological diagnosis of invasive mammary cancer. Methods: Computed tomography (CT), to search for metastases, incidentally revealed an ileocecal mass. Endoscopy of the lower intestinal tract detected an extramural mass, and the subsequent biopsy result was negative for neoplasm. The patient underwent laparoscopic ileocecal resection and total right mastectomy. A lob- ulated gray-whitish, cecal tumour, measuring 58x45x35 mm, was identified from the muscularis propria to the subserosal membrane. Results: Histopathologically, spindle cell sarcoma with nuclear polymorphism as well as mitotic activity showed distinct eosinophilic myofilaments in the cytoplasm. Immunohistochemi- cally, cancer cells were diffusely positive for desmin, α-SMA, and h-caldesmon. These findings were considered to indicate leiomyo- sarcoma. In addition, the right breast cancer corresponded to a primary neuroendocrine neoplasm. A right adrenal tumour was detected by CT performed to assess a right ureteral stone 55 months after the operation. The morphological findings were similar to those of the cecal tumour, accompanied by strong α-SMA and h-caldesmon immuno-expressions. Both lesions were positive for MDM2, CDK4 and S-100, and showed amplification of the MDM2 gene on FISH analysis. Conclusion: Based on these pathological features, we made the final diagnosis of dedifferentiated liposarcoma with the leiomyo- sarcoma phenotype. Within the searchable range, we identified no well-differentiated components. Retrospectively, our present cecal tumour might have originated from the subserosal layer or the peritoneum, and then progressed to involve the muscularis pro- pria. In conclusion, from the therapeutic perspective, it is worth considering the possibility of well-differentiated/dedifferentiated liposarcoma in retroperitoneal and intraperitoneal mesenchymal neoplasms even when the histology is not typical. Funding: Tomonori Kawasaki is supported by Grants-in-Aid for Scientific Research (No. 21K06910 and No. 20K08131) from the Japanese Ministry of Education, Culture, Sports, Science and Technology and the National Hospital Organization (NHO) Grant (H29-NHO-01). E-PS-06-044 Glomangioma of stomach mimicking GIST: case report T. Pasupati Meenakshi*, B. Karikalan *Gribbles Pathology M Sdn Bhd, Malaysia Background & objectives: Glomangioma of stomach is an extremely rare entity and can clinically present with gastrointestinal bleeding. A case of glomangioma of distal stomach with haematemesis, clinically suspected as a GIST tumour of stomach is documented. Methods: A 58-year-old female presented with haematemesis. CT scan revealed a distal stomach mass with features suspicious of GIST. A partial gastrectomy performed showed a submucosal tumour in the distal stomach, measuring 31x22x26mm. The lesion was soft, fleshy and lobulated. Rest of the stomach was unremark- able. Routine H&E and IHC studies were carried out to document the nature of the tumour. Results: H&E sections showed a well delineated submucosal tumourous lesion exhibiting uniform, diffuse distribution of monot- onous appearing cells with relatively scanty cytoplasm and dense nuclei, without any atypia. Tumour cells were arranged in small and large groups and nests, surrounding small and a few ectatic blood vessels, with scant intervening oedematous stroma. The tumour was infiltrating into the upper third of muscularis propria. IHC studies showed a strong expression for SMA, CD34 with total lack of expression for CD117, Chromogranin, Synaptophysin and pan CK. Ki 67 showed a very low proliferative index of 2%. Mor- phological features and further IHC studies confirmed a benign glomus tumour(glomangioma) of distal stomach. Conclusion: Glomangioma of stomach can mimic GIST or neuroendocrine tumour and present with GI bleeding. An entity of submucosal lesion of stomach should include the rare entity of glomangioma in the differential diagnosis and IHC studies are warranted in such cases for further accuracy, and documentation. The benign or malignant nature of the glomangioma aids in further management of the case. S228