Environmental Risk Factors for Signet Ring Cell Colorectal Carcinoma in Low Risk Populations

Abstract

Colorectal cancer (CRC) is the second leading cause of death in western countries. Historically, 20-25% of individuals with CRC have significant risk factors such as age, lifestyle, associated medical conditions or polygenic inheritance, placing them as high-risk. Screening guidelines exist for high-risk populations however there is limited data for young, low risk patients.?? Overall, only 2-3% of CRCs occur in young adults and are mainly associated with aggressive, sporadic malignancies such as mucinous and signet ring cell colon cancer (SRCC). The latter, representing an independent, poor prognostic factor and a 42-57% higher risk of death. We present the case of a 24-year-old Hispanic male from El Salvador with no previous medical history who noticed 6 months of persistent, progressive constipation with accompanying change in caliber to a “pencil sized” diameter. Our patient was self medicating with lactulose however following an inability to void for five days, he presented to the Emergency Department. He has a family history significant for a brain tumor in his brother and lymphoma in his maternal aunt. The patient was an agricultural worker until immigrating to the United States. ??His physical exam was significant for diffuse abdominal tenderness and distension. Abdominal CT scan revealed a partial obstruction in the mid sigmoid colon and a subsequent colonoscopy showed an obstructing mass 15cm from the anal verge. Surgical biopsy of the mass revealed it to be an invasive, poorly differentiated SRCC.?? A palliative colostomy was created due to the presence of carcinomatosis and the unresectable nature of the malignancy. He unfortunately has a poor prognosis and only palliative measures will be pursued for his care. It is our hypothesis that either a germ line mutation or exposure to agricultural carcinogens will ultimately be implicated in our patient's SRCC. Agricultural exposure has been linked to various cancers however the impact of environmental factors in the pathogenesis of SRCC is still unexplored. Insecticides and agricultural compounds may constitute the necessary milieu for the development of genetic mutations as evidenced by our patient's development of SRCC. This case depicts a young patient who presented with an advanced stage of a rare malignancy. His classic symptomatology and presentation of chronic, progressive constipation may have prompted earlier detection and improved prognosis if pursued promptly.