PMC8206524_01
Gd-EOB-DTPA enhanced MRI of this patient. (A) T1-weighted MRI showing that the liver nodules (red arrows) were highly intense. (B) T2-weighted MRI, showing that the liver nodules were iso-intense. (C) Gd-EOB-DTPA-enhanced MRI, showing the showed were highly intense during the hepatobiliary phase. (D) Plain-CT examination 1 year before liver biopsy, showing small, high-density nodules. (E) FDG-PET CT examination at liver biopsy. No abnormal FDG uptake was detected. (F-H) Dynamic CT examination during the (F) arterial, (G) portal phase, and (H) equivalent phases. No enhancement was detected.
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Figure 1A ), iso-intensity on T2 weighted imaging ( Figure 1B ), and high-intensity on hepatobiliary phase of gadolinium-ethoxybenzyl-diethyleneaminepantaacetic acid (Gd-EOB-DTPA)-enhanced MRI ( Figure 1C ). Five years earlier, he had undergone curative enucleation of his left eye for uveal melanoma, but he was asymptomatic during this 5-year period. Retrospective examination, however, identified small hyperdense small nodules on the plain phase of FDG-PET/CT at least 1 year earlier ( Figures 1D, E ). These nodules were not enhanced on dynamic CT ( Figures 1F-H ) but were hypoechoic on B-mode ultrasonography (US) ( Figure 2A ).
US findings. (A) B-mode US, showing tiny hypoechoic nodules. (B, C) Sonazoid enhanced US during (B) early and (C) delayed vascular phases. A perfusion defect was also observed during the delayed phase.
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These nodules were not enhanced on dynamic CT ( Figures 1F-H ) but were hypoechoic on B-mode ultrasonography (US) ( Figure 2A ). On Sonazoid-enhanced US, these nodules showed strong enhancement during early arterial phase ( Figure 2B ) and were hypoechoic on delayed phase ( Figure 2C ), suggesting that these nodules were liver metastases of uveal melanoma.Macroscopic examination of US-guided biopsy specimens of the liver nodules showed black pigmentation ( Figure 3A ).
Histological findings. (A, B) Hematoxylin-eosin (HE) staining (A, X4; B, X200). (C) Melan-A staining (X400). (D) MIB-1 staining (X400). (E, F) CD4 staining (E, X100; F, X400); T indicates tumor area, N indicates non-tumor area. (G, H) CD8 staining (G, X100; H, X400). (I) Number of infiltrating cells. Y-axis represents the number of infiltrating cells. The average number of cells in three high power fields is shown. Black bar means the number of cells in tumor area, whereas white bar means that of non-tumor area. Asterisk indicates statistical significance (p<0.05).
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On Sonazoid-enhanced US, these nodules showed strong enhancement during early arterial phase ( Figure 2B ) and were hypoechoic on delayed phase ( Figure 2C ), suggesting that these nodules were liver metastases of uveal melanoma.Macroscopic examination of US-guided biopsy specimens of the liver nodules showed black pigmentation ( Figure 3A ). Pathological evaluation showed proliferation of abnormally pigmented tumor cells ( Figure 3B ), which were positive for Melan-A ( Figure 3C ), HMB45 and S100 (data not shown), confirming that these nodules were hepatic metastases of uveal melanoma. The highly proliferative nature and aggressive phenotype of these tumor cells were confirmed by high MIB-1 expression ( Figure 3D ). Immunohistochemical staining also showed infiltration of CD8, but not CD4, positive lymphocytes into metastatic nodule ( Figures 3E-H ). The number of CD8 positive lymphocytes was increased in the metastatic tumor as compared with non-tumor area and that of CD4 ( Figure 3I ).
Clinical course of present case with images. Red arrow and arrow head indicate the metastatic tumors detectable with imaging studies.
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He has experienced no change in the size or radiological pattern of these nodules for 1 year after presentation ( Figure 4 ).