The efficacy of preoperative imaging for acral melanoma (AM) has not been fully evaluated. We examined the accuracy of imaging modalities in the detection of nodal and distant metastases in patients with AM. A retrospective review of 109 patients with AM was performed. All patients had no clinical signs suggestive of distant metastases, and underwent preoperative screening computed tomography (CT) and positron emission tomography (PET)/CT scans. Of 100 patients without lymphadenopathy, 17 patients were suspected of having nodal metastasis in CT and PET/CT, but only two of them were confirmed on histopathological analysis. On the other hand, 12 out of 83 negatively imaged patients showed histopathological signs of nodal metastasis; thus, the sensitivity and specificity of nodal detection were 14.3% and 82.6%, respectively. Regard to the detection of distant metastases, four patients were suspected of having metastasis, but this was later ruled out. The remaining 96 negatively imaged patients were confirmed to have no metastasis at the time of CT and PET/CT by the follow-up. In contrast, distant metastases were found by CT and PET/CT in four of nine patients (44.4%) with lymphadenopathy. Routine preoperative CT and PET/CT for AM patients without lymphadenopathy may not be warranted because of low sensitivity and specificity, but it can be considered for those with lymphadenopathy.
Keywords: acral melanoma; computed tomography; metastasis; positron emission tomography; prognosis; sentinel lymph node.