Mixed Adenoneuroendocrine Carcinoma of Cecum: A Rare Entity
A 68-year-old female presented to the Radiology Department with complaints of abdominal pain and vomiting. In spite of conservative treatment her condition worsened. She was unable to pass stools for a week and subsequently developed abdominal distension. There was no history of fever or weight loss and her abdominal examination revealed guarding and rigidity in the right iliac fossa.\nContrast enhanced computed tomography (CT) of abdomen and pelvis done on Asteion Toshiba single-slice spiral CT scanner revealed ileocolic intussusception with the lead point being an intraluminal heterogeneously enhancing mass in the cecum with associated irregular wall thickening [Figures and ] resulting in small bowel obstruction. The mass measured 3 × 3.5 cm in size. Few of the distal ileal loops showed thickened walls with mesenteric haziness in the right iliac fossa and minimal ascites, multiple enlarged mesenteric nodes ranging from 10 to 14 mm were seen in the right lumbar and the right iliac fossa with few of them showing central necrosis [].\nPatient underwent right hemicolectomy. Cut surface revealed a polypoidal growth in the cecum measuring 3.5 × 3.0 × 2.5 cm. Macroscopic tumor perforation was present and microscopically tumor was adherent to other organs and was infiltrating the peritoneum, pericolic fat, and appendicular wall. Serosal margin was infiltrated by the tumor. The proximal and distal resected margins of the specimen were free from tumor involvement. Thirteen out of 14 lymph nodes were positive.\nHistopathology examination of the cecal mass revealed sheets, cords, and islands of monomorphic large cells with large round nucleus and abundant cytoplasm [Figure and ] infiltrating the layers of cecum up to the peritoneum. Nests and islands of tumor with vague glandular structures amounting to more than 30% of the tumor [Figure and ] were seen originating from cecal mucosa and infiltrating the wall amidst pools of extracellular mucin. Few signet ring cells were seen interspersed between the large tumor cells. Focal aggregate of lymphocytes was also seen []. The final histopathological diagnosis was MANEC of the cecum, poorly differentiated to undifferentiated, having >20 mitotic count per 10 high-power field, nodal metastases, tumor Stage T4 N2 M0.\nImmunohistochemical examination revealed caudal-related homebox transcription factor 2 (CDX2), cytokeratin 20, synaptophysin, and carcino-embryonic antigen were strongly positive. There was focal positivity for chromogranin. While Ki-67 showed high proliferative index amounting to more than 20% of the tumor tissue.