Ulcerated colonic mucosal fragments by related malignant infiltrate formed of large round cells with hyperchromatic nuclei and eosinophilic cytoplasm . The infiltrate is admixed with inflammatory cells. Anaplasia is marked and mitosis is active. Wide areas of necrosis are observed. The main possibility is poorly differentiated adenocarcinoma. However, marker study (CK, Synaptophysin,, CD20, and LCA) is recommended for confirmation and exclusion of the less likely other possibilities.
Abdominal pain and constipation. Colonoscopy: huge polypoidal ulcerated mass involving the cecum and ascending colon.
Fragments of collective size 9x7 mm.
Ascending and colonic mass, endoscopic biopsy: