Hepatocellular Carcinoma (HCC) Metastasis to the Diaphragm Muscle: A Systematic Review and Meta-Analysis of Case Reports.

The purpose of this study was to conduct a systematic review and meta-analysis of case reports presenting HCC spread to the diaphragm muscle and to determine possible risk factors for this condition. An extensive literature search was performed using the following electronic databases: MEDLINE, CINAHL, ScienceDirect, Google Scholar, and DOAJ. A total of 18 articles describing 27 hepatocellular carcinoma patients were included in this review. The presence of HCC cells in the superior liver segment is strongly associated with metastases to the diaphragm. Among the two types of diaphragm involvement by HCC cells, diaphragm infiltration occurs much more frequently than diaphragm adhesion. However, an HCC nodule in the 8th liver segment and a higher number of liver segments involved by HCC cells predispose patients to diaphragm adhesion. Hepatitis B is a risk factor for diaphragm metastases in recurrent HCC. The tumor diameter is not associated with HCC spread to the diaphragm muscle. We did not find specific symptoms reported by patients that could indicate HCC metastasis to the diaphragm muscle. The presence of hepatitis B and the localization of HCC cells in superior liver segments, especially in the 8th liver segment, should be take into consideration in the diagnostic process.