Differential Diagnosis for Rectal Mass

• Single most likely diagnosis
  • Rectal Carcinoma: This is the most common cause of a rectal mass, especially in older adults. The justification for this diagnosis is based on the high prevalence of colorectal cancer and the typical presentation of a rectal mass.
• Other Likely diagnoses
  • Hemorrhoids: Although often not considered a "mass," large hemorrhoids can present as a palpable rectal mass. This diagnosis is likely due to the common occurrence of hemorrhoids in the general population.
  • Rectal Polyps: These are growths on the inner lining of the rectum and can be felt as a mass. They are relatively common and can be precancerous, making them a plausible diagnosis.
  • Rectal Abscess: An abscess in the rectum can present as a painful mass. This diagnosis is considered due to the potential for infection in the rectal area.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
  • Lymphoma: Although rare, lymphoma can present as a rectal mass and is critical to diagnose early due to its potential for aggressive behavior and the importance of timely treatment.
  • Gastrointestinal Stromal Tumor (GIST): A rare tumor of the digestive tract that can occur in the rectum. It's crucial not to miss this diagnosis because GISTs can be malignant and require specific treatment.
  • Metastasis: Rarely, a metastatic lesion from another primary cancer can present as a rectal mass. Missing this diagnosis could significantly impact treatment and prognosis.
• Rare diagnoses
  • Rectal Melanoma: A rare type of cancer that originates in the rectum. It's essential to consider due to its aggressive nature and poor prognosis if not treated promptly.
  • Rectal Neuroendocrine Tumors: These are rare tumors that arise from neuroendocrine cells in the rectum. They can vary from benign to highly malignant, making early diagnosis crucial.
  • Rectal Leiomyosarcoma: A rare smooth muscle tumor that can occur in the rectum. It's considered due to its potential for malignancy and the need for specific management.