Clinicopathological study of surgery for pulmonary metastases of
hepatoblastoma with indocyanine green fluorescent imaging
Abstract
Background: The prognosis of metastatic hepatoblastoma remains poor; to
improve it, pulmonary metastasis must be controlled. Indocyanine green
(ICG) fluorescent imaging has been used recently for lung
metastasectomy. The objective of our study was to clarify the usefulness
of ICG imaging for lung metastasectomy of hepatoblastoma using detailed
clinicopathological analysis. Procedure: Patients with hepatoblastoma
who underwent resection of pulmonary metastases with ICG fluorescent
imaging were studied using retrospective analysis of clinical
information, a review of their surgical records, and a histological
analysis of their metastatic nodules. Results: Sixteen patients were
enrolled. In total, 61 ICG-imaging-guided pulmonary metastasectomies
were performed, and 350 ICG-positive and 23 ICG-negative specimens were
identified. Tumors were confirmed in 250 of the ICG-positive specimens,
including eight nonpalpable nodules, on microscopic examination. One
hundred ICG-positive specimens and histologically tumor-negative
specimens showed histological changes suggesting the regression of a
tumor or bloodstream disturbance. The palpable ICG-negative tumors
showed more-severe atypia than the ICG-positive tumors. Conclusions:
This study demonstrates the high sensitivity of ICG imaging in detecting
metastatic lesions of hepatoblastoma. Histological examinations
suggested that ICG imaging detects not only tumor cells, but also
nontumorous pulmonary tissues affected by bloodstream disturbance.
Because a number of false-positive specimens were detected, further
optimization of the dose of ICG and the timing of its administration may
be required for thorough metastasectomy. Several false-negative
specimens were also detected, suggesting the presence of ICG-negative
metastatic tumors. Palpation during operation and imaging studies remain
essential for detecting metastatic lesions, even in the era of ICG
imaging.