頭蓋骨転移を来した肝細胞癌の1例

Skull Metastasis of Hepatocellular Carcinoma ： Case Report

Ⅰ．はじめに

　肝細胞癌（HCC：hepatocellular carcinoma）は高率に他臓器転移を来すが，その多くは肺，所属リンパ節，腹腔内臓器への転移である．従来，頭蓋骨への転移は極めて稀であると報告されてきた^{1,2, 7-11,13,14,16,17,19,20)}が，近年では原疾患の予後向上とも相まって増加傾向にあり，以前ほど稀な病態ではなくなってきている^3,5,18)．本論文では，最近経験したHCCからの頭蓋骨転移症例を報告し，近年における本疾患の臨床的および画像診断学的特徴について文献的考察を加える．

We report a case of skull metastasis from a hepatocellular carcinoma (HCC). A 68-year-old male with hepatitis C virus-associated cirrhosis and HCC presented with painless subcutaneous mass in the left frontotemporal region. Radiologically,skull X-ray showed an osteolytic lesion,and non-contrast CT displayed a hyperdense tumor that homogeneously enhanced on contrast CT. Cerebral angiography demonstrated a hypervascular mass with the feeding arteries from the external carotid artery. The tumor was shown as an iso-intensity mass with flow voids on T1WI,as iso- to hypo- intensity on T2WI and FLAIR images,and as hypo-intensity on DWI. The lesion was markedly enhanced by Gd-DTPA.

　Previous reports have described a low incidence of skull metastasis in HCC patients. However,the incidence is gradually increasing due to the prolonged survival rates of HCC patients,indicating the significance of the disease as a differencial diagnosis for skull tumors. Recent reports describe characteristic MRI findings of skull metastasis from HCC (hypointensity on T2WI with flow void); however,owing to the rarity of this disease,more studies are needed to establish the typical MRI pathognomonic findings.