ECP 2022 Abstract Book

Virchows Archiv (2022) 481 (Suppl 1):S1–S364 13 serrated carcinoma pathway is estimated to account approximately for 10–30% of all CRCs. Conclusion: Establishing the fact that serrated adenocarcinomas can be distinguished from traditional CRCs, we propose that CK7 and CK20 IHC analysis alongside adequate sampling of the tumour & adjacent non-neoplastic colorectal mucosa should be implemented when handling specimens. Increasing awareness in the scientific community in the reporting of serrated lesions, may consequently benefit patients with their likely prognosis and treatment. E-PS-06-057 Neuroendocrine tumour arising from a Meckel’s diverticulum: a rare entity S. Frini*, A. Baccouche, W. Majdoub, A. Bdioui, S. Mestiri, S. Hmissa *Pathology Department, Sahloul University Hospital of Sousse, Tunisia Background & objectives: Meckel’s diverticulum (MD), a vestigial remnant of vitelline duct, represents the most common abnormality of the gastrointestinal tract. Its malignant transformation is an unusual event. Herein, we report a case of a neuroendocrine tumour arising in the setting of MD. Methods: We report the case of a 86 years-old man, with a history of peptic ulcer disease, who presented with symptoms of bowel obstruction. Blood tests showed a biological inflammatory syn- drome and radiological exams concluded to a complicated MD. He underwent a cuneiform resection of the MD with uneventful post operative follow-up. Results: Histological examination revealed the presence of a 0.8 cm well-differentiated neuroendocrine tumour invading the mucosa and the sub-mucosa. Tumour cells displayed an insular pattern and were focally arranged in rosettes. The tumour cells were monotonous, had an eosinophilic granular cytoplasm and small round nuclei with ‘salt and pepper’ chromatin. No mitotic figures were seen. Immunohistochemically, these cells were positive for synaptophysin and chromogranin A. The Ki-67 was expressed in less than 1% of tumour cells. Surgical margins were negative. The diagnosis of well-differentiated neuroen- docrine tumour (Grade I) arising in a Meckel’s diverticulum was established. Conclusion: Eventhough it’s scarce, neuroendocrine tumours should be taken into account when dealing with Meckel’s divr- ticulum. Despite its small size, it is frequently associated with nodal and liver metastasis. An optimal surgical management and a close follow-up are advised. E-PS-06-058 Adenosquamous carcinoma of the colon: study of 5 cases S. Moussa*, W. Majdoub, M. Krifa, A. Baccouche, O. Belkacem, S. Ben Cheikh, A. Bdioui, S. Hmissa *Pathology department, Sahloul University Hospital of Sousse, Tunisia Background & objectives: Adenosquamous carcinoma (ASC) is an extremely rare subtype of colo-rectal cancer (CRC) with an incidence lower than 0.1% of all CRC. ASC shows an admixture of both adenocarcinoma and squamous cell carcinoma. We aim to describe clinico-pathological aspects of ASC. Methods: We performed a retrospective study of 5 cases of patients diagnosed in our department with ASC collected in our institution over a period of 20 years from 2000 to 2020. Results: Our study included 5 males. Patient’s age ranged from 17 to 68years with an average of 50years. One of the patients had family history of CRC and personal history of high-grade conventional adenoma. ASC were widely disbursed throughout the colon with primary sites including the caecum (2cases) and the sigmoid (2cases), followed by the rectum (1case). Histologically, most ASC were of low-grade (4cases) and presented as stage III (3cases). Stages II and IV were identified each in 1case. All patients received adjuvant chemotherapy. One patient relapsed with local and metastatic forms. Three patients died and two were lost at follow up. The follow up average duration was estimated to 6.4months. Conclusion: The clinical features are similar to other subtypes of adenocarcinoma. Treatment is based on surgery since the benefit of chemotherapy and radiotherapy is not well established. Because of the rarity of this subtype and its generally aggressive nature, no specific prognostic features have been identified. Few series have been reported including a small number of patients. The overall prognosis is worse than adenocarcinoma NOS of the colon across all stages. E-PS-06-059 Ulcerated colonic lipoma mimicking a gastrointestinal stromal tumour in Von Recklinghausen’s disease S. Frini*, A. Bdioui, S. Moussa, W. Majdoub, O. Belkacem, A. Baccouche, S. Hmissa *Pathology Department, Sahloul University Hospital of Sousse, Tunisia Background & objectives: Von Recklinghausen’s Disease (VRD) predisposes to the development of various tumours, ranging from benign neurofibromas to malignant peripheral nerve sheath tumours. Among this spectrum, Colonic lipomas are extremely rare. Herein, we discuss clinico-pathological features of a tumour with misleading presentation. Methods: A 29-year-old women with VRD presented with melena and symptoms of intermittent bowel obstruction. Computed tomography and colonoscopy were performed and suspected a gastrointestinal stromal tumour in the ascending colon. Con- sidering the patient’s background and an inconclusive biopsy, she underwent a right colectomy with uneventful post-operative course. Results: Gross examination revealed the presence, of a 4 cm well- circumscribed exophytic mass in the caecum. The tumour was covered by an ulcerated mucosa. Cut section showed a homog- enous, fatty appearance. Histologically, the tumour was composed of lobules of mature adipocytes with cellular fibrous septa. The spindle cells in the septa were negative to PS100, C-Kit, Dog 1 and SMA stains. The remaining mucosa showed a mild chronic inflammation. The final diagnosis concluded to a lipoma of the colonic mucosa. Conclusion: It is still unknown whether the coexistence of colonic lipoma with VRD was a mere coincidence or an intrinsic associa- tion; and to our knowledge, only one case has ever reported this occurrence. Due to the variable expressivity of VRD and its sys- temic manifestation, a multi-disciplinary approach should always be considered. S232