Sinonasal Intestinal type Adenocarcinoma (ITAC) Our insights from a rare clinical case: a case report

Background: Intestinal-type adenocarcinoma is the second most common sinonasal adenocarcinoma. It develops through intestinal metaplasia of sinonasal epithelium, characterized by strong resemblance to carcinoma of colon and considered to be rare. These are aggressive tumours generally diagnosed in the advanced stage. Histopathological subtype is an important prognostic indicator. Case Report: A 51 year old male patient presented with complaints of right nasal obstruction since 4 months, history of blood stained nasal discharge occasionally. On nasal endoscopy, a single irregular exophytic mass bulging into nasal cavity originating from right side upper part of posterior nasal septum was seen. Excision of mass and right side full functional endoscopic sinus surgery with septoplasty were done. Histopathological examination showed invasive tumor arranged predominantly in papillary architecture with focal tubule formation and was diagnosed as sinonasal intestinal type adenocarcinoma, well differentiated, papillary subtype. Immunohistochemistry showed tumour is focal positive for CK7 and positive for CK20, CDX2, SATB2. Conclusion: Intestinal-type adenocarcinoma (ITAC) is the second most common type of sinonasal adenocarcinoma after adenoid cystic carcinoma and has better prognosis compared with squamous cell carcinomas. Standard treatment is surgical resection, with a minimally invasive endoscopic approach when possible, followed by chemoradiotherapy.