Large retrorectal spindle cell sarcoma: A case report and brief review of the literature.

Large retrorectal tumors are rare and often a diagnostic and surgical challenge due to their anatomical location. We report the case of a 55-year-old patient with weight loss and changed bowel habits, where digital rectal examination revealed a retrorectal mass raising suspicion of a tumor. Magnetic resonance imaging (MRI) and computed tomography (CT) showed a large retrorectal tumor and histopathology after surgical resection showed undifferentiated spindle cell sarcoma. This tumor type has not been previously reported as the etiology of large retrorectal tumors. We discuss the implications of diagnostic imaging, especially MRI, in the approach to diagnosis and surgical treatment of retrorectal tumors with reference to the scientific literature and previously reported cases of retrorectal tumors.

Diagnostic accuracy of CT for local staging of colon cancer: A nationwide study in the Netherlands.

OBJECTIVE: To determine the accuracy of computed tomography (CT)-based staging in selecting high-risk colon cancer patients who would benefit from neoadjuvant chemotherapy while avoiding overtreatment. METHODS: Data of adult patients diagnosed with non-metastatic primary colon cancer in 2005-2020, who underwent surgical resection without neoadjuvant chemotherapy, were retrospectively collected from the Netherlands Cancer Registry. Agreement between clinical and pathological evaluation for each T and N stage was calculated. Sensitivity and specificity analyses were conducted to predict T3-T4 and N1-N2 stages, with histopathology as the reference standard. RESULTS: Data from 44,471 patients (median age, 71 years, 50% female) were evaluated. We included 38,915 patients with complete T stage and 39,565 patients with complete N stage for analyses. The overall clinical-pathological agreement for T stage was 59% and for N stage 57%. The sensitivity and specificity of CT to detect T3-T4 tumours were 80% (95% confidence interval (CI): 0.79, 0.80) and 76% (95% CI: 0.75, 0.77), respectively, with a positive predictive value (PPV) of 92% (95% CI: 0.92, 0.92). The sensitivity and specificity of CT to detect N1-N2 category were 62% (95% CI: 0.61, 0.63) and 70% (95% CI: 0.69, 0.71), respectively, with PPV 60% (95% CI: 0.59, 0.60). CONCLUSION: CT-based staging shows limited accuracy in selecting colon cancer patients who would benefit from neoadjuvant therapy without risking overtreatment. Detection of lymph node metastases with CT remains unreliable.