Abstract

1. Background

Rectal squamous adenocarcinoma is a rare primary rectal malignancy compared to the common colorectal adenocarcinoma. Due to the low incidence of this cancer at 0.1% the pathogenesis and risk factors are based on few case reports and case series [7]. It is believed to be directly linked to the complex inflammatory process caused by the Human Papilloma Virus (HPV), specifically serotype 16 and 18 [3]. Here we present a case report on a 45-year-old female who was found to have a distal mass that required careful pre-operative planning to complete surgical intervention with R0 resection. Her past medical history includes a complex sclerosing breast lesion with abnormal fibrocystic changes s/p lumpectomy, but HPV negative who presented with over 6 months of constipation that recently worsened to include rectal bleeding. Imaging revealed a distal circumferential mass that was compressing the rectum. Biopsy revealed poorly differentiated squamous rectal adenocarcinoma. Ultimately the patient needed neoadjuvant therapy and surgery intervention, which required lysis of adhesions, resection of omentum, takedown of splenic flexure and subtotal proctectomy. Exophytic squamous rectal adenocarcinoma varies in general GI symptoms and the distal location makes it difficult to resect. The prognosis and probability of surgical intervention depends on early staging, size of neoplasm, and invasion of nearby structures. In this case, RO resection was successfully performed. Rectal squamous adenocarcinoma is associated with HPV, STDs, history of anal intercourse, HIV, presence of precancerous anal lesions such as condylomas or high grade intraepithelial anal/ cervical/vulvar/vaginal neoplasia, and smoking. This subtype of anal cancer is extremely rare. Its tumor size, nodes, and metastasize as well as clinical staging determines patient prognosis.