Retrospective Evaluation of Discrepancies between Radiological and Pathological Size of Hepatocellular Carcinoma Masses

Background: The size of a hepatic neoplasm is critical for staging, prognosis and selection of appropriatetreatment. Our study aimed to compare the radiological size of solid hepatocellular carcinoma (HCC) masseson magnetic resonance imaging (MRI) with the pathological size in a Chinese population, and to elucidatediscrepancies. Materials and
Methods: A total of 178 consecutive patients diagnosed with HCC who underwentcurative hepatic resection after enhanced MRI between July 2010 and October 2013 were retrospectively identifiedand analyzed. Pathological data of the whole removed tumors wereassessed and differences between radiologicaland pathological tumor size were identified. All patients were restaged using a modified Tumor-Node-Metastasis(TNM) staging system postoperatively according to the maximum diameter alteration. The lesions were classifiedas hypo-staged, iso-staged or hyper-staged for qualitative assessment. In the quantitative analysis, the relativepre and postoperative tumor size contrast ratio (%Δsize) was also computed according to size intervals. Inaddition, the relationship between radiological and pathological tumor diameter variation and histologic gradewas analyzed.
Results: Pathological examination showed 85 (47.8%) patients were overestimated, 82 (46.1%)patients underestimated, while accurate measurement by MRI was found in 11 (6.2%) patients. Among thetotal subjects, 14 (7.9%) patients were hypo-staged and 15 (8.4%) were hyper-staged post-operatively. Accuracyof MRI for calculation and characterized staging was related to the lesion size, ranging from 83.1% to 87.4%(<2cm to ≥5cm, p=0.328) and from 62.5% to 89.1% (cT1 to cT4, p=0.006), respectively. Overall, MRI misjudgedpathological size by 6.0 mm (p=0.588 ), and the greatest difference was observed in tumors <2cm (3.6 mm,%Δsize=16.9%, p=0.028). No statistically significant difference was observed for moderately differentiated HCC(5.5mm, p=0.781). However, for well differentiated and poorly differentiated cases, radiographic tumor maximumdiameter was significantly larger than the pathological maximum diameter by 3.15 mm and underestimated by4.51 mm, respectively (p=0.034 and 0.020).
Conclusions: A preoperative HCC tumor size measurement usingMRI can provide relatively acceptable accuracy but may give rise to discrepancy in tumors in a certain size rangeor histologic grade. In pathological well differentiated subjects, the pathological tumor size was significantlyoverestimated, but underestimated in poorly differentiated HCC. The difference between radiological andpathological tumor size was greatest for tumors <2 cm. For some HCC patients, the size difference may haveimplications for the decision of resection, transplantation, ablation, or arterially directed therapy, and shouldbe considered in staging or selecting the appropriate treatment tactics.