CT characteristics and differential diagnosis of tumor deposition adjacent to colorectal cancer

Abstract

Objective To summarize the CT characteristics of tumor deposition adjacent to colorectal cancer (CRC), and provide the evidences for differential diagnosis. Methods The retrospective cross-sectional study was conducted. The clinicopathological data of 26 CRC patients who were admitted to the Wuxi Second People′s Hospital of Nanjing Medical University from May 2015 to April 2017 were collected. Patients underwent preoperative multi-slice spiral CT scan and double-phase enhanced scan, and then received open surgery. Observation indicators: (1) characteristics of multi-slice spiral CT scan; (2) differential comparisons; (3) follow-up. Follow-up using telephone interview was performed to detect patients′ prognosis once every 3 months up to May 2017. Measurement data with normal distribution were represented as ±s. Comparisons between groups and among groups were respectively analyzed using the t test and the one-way ANOVA. Pairwise comparison was done using the SNK method. Results (1) Characteristics of multi-slice spiral CT scan: of 26 patients, 17 underwent double contrast enhanced scans of chest, abdomen and pelvic and 9 underwent double contrast scans of abdomen and pelvic. Primary tumors of 18 and 8 patients respectively located in the colon and rectum. Forty-one tumor deposits of 26 patients were collected, with number of tumor deposits of 1.6±0.9 per case, and number of tumor deposits 0.05). There were statistically significant differences in the plain scan value of CT and CT enhancement values in the arterial phase between tumor deposits and metastatic lymph nodes (q=5.48, 2.50, P 0.05). Of 19 metastatic lymph nodes, 11 demonstrated homogeneous density in plain scan, with a lower density compared with tumor deposits and primary tumors, and relatively homogeneous enhancement in the arterial phase of enhanced scan; 8 demonstrated heterogeneous density with internal liquefaction necrosis, and ring-shaped enhancement in enhanced scan with no enhancement in the areas of necrosis. The density and enhancement range in the arterial phase and venous phase of tumor deposits were similar to primary tumors. (3) Follow-up: 24 patients were followed up for 1-25 months, with a follow-up rate of 92.3%(24/26) and a median time of 17 months. Of 24 patients, 2 were dead, and survival time were respectively 9 months and 21 months; 22 had good survival. Conclusions Multislice spiral CT examination of tumor deposits demonstrates larger and irregular shape, with the signs of lobulation and burr, and the density in plain scan is similar to the primary tumor, with obviously enhancement in early enhanced scan. The metastatic lymph nodes are mostly round-like shape, diameter is smaller than that of tumor deposits, density in the plain scan and CT enhancement values in the arterial phase are lower than that of tumor deposits. Key words: Colonic neoplasms; Rectal neoplasms; Tumor deposition; Lymph node metastases; Tomography, X-ray computed