Hatim Vajihi, MD1, Prashanth Rau, MD2, Deepika Devuni, MD3, Kanishka Bhattacharya, MD, MRCP3; 1UMass Memorial Medical Center, Andover, MA; 2UMass Memorial Medical Center, Worcester, MA; 3University of Massachusetts Medical Center, Worcester, MA
Introduction: Colorectal cancer is one of most common and lethal cancers in the world. Adenosquamous carcinoma (ASC) of the colon, which contains adenocarcinoma and squamous carcinoma, is one of the subtypes which account for 0.025% to 0.1% of all colon cancers. Only one case report exists in the literature which shows ASC of the colon in Ulcerative Colitis (UC). We present a case of a patient with UC who had a rapid onset (< 2 years) of ASC of the transverse colon.
Methods: 64-year-old male with pan ulcerative colitis well controlled on sulfasalazine presented with 5 days of bright red blood per rectum with abdominal pain. CT abdomen and pelvis showed large apple core lesion of the transverse colon as well as intrahepatic ductal dilation. Colonoscopy showed a large mass which was biopsied that showed moderately differentiated invasive squamous cell carcinoma. PET/CT showed intense FDG uptake at the splenic flexure. Given his presentation and unusual pathology of squamous cell carcinoma, he underwent colectomy. Pathology from colectomy showed moderately differentiated ASC. The patient also had a lesion in the liver which was biopsied and was found to have squamous cell carcinoma on pathology. Of note, patient had a colonoscopy 1 year prior to current presentation which only showed moderately eroded, scarred and ulcerated mucosa in the whole colon. Biopsy at that time showed chronic active colitis without any high-grade dysplasia. Discussion: Mechanism for ASC remains unclear. Longstanding chronic inflammation can lead to apparent stimulation that leads to differentiation of uncommitted cells to squamous epithelium. Our case demonstrates that UC may play a role in formation of ASC of the colon. Importance of histologic remission can also be demonstrated in our case as our patient had chronic active colitis on prior biopsy but was not started on any treatment. Initiation of treatment for histologic changes even without clinical manifestation may prevent progression to ASC.
Also, ASC of the colon consists of 2 components (adenocarcinoma and squamous carcinoma). Initial biopsy only revealed squamous carcinoma without glandular adenocarcinoma. Mixed ASC was discovered on the resected specimen after colectomy. Patient had a biopsy of the liver due to a questionable lesion which also only revealed squamous cell carcinoma without any adenocarcinoma component. Hence, it is essential to get adequate passes of biopsy and from different region of the mass to allow early detection of the aggressive ASC.
Disclosures: Hatim Vajihi indicated no relevant financial relationships. Prashanth Rau indicated no relevant financial relationships. Deepika Devuni indicated no relevant financial relationships. Kanishka Bhattacharya indicated no relevant financial relationships.