Spontaneous Pathological Complete Regression of Hepatocellular Carcinoma.

Several possible mechanisms for spontaneous regression of hepatocellular carcinoma (HCC) have been reported. Spontaneous complete regression of HCC is extremely rare. We herein report a case of spontaneous pathological complete regression of HCC following decrement of elevated serum alpha-fetoprotein (AFP). The serum AFP of a 74-year-old man who underwent hepatic resection for HCC twice increased up to 7,529 ng/mL and then spontaneously decreased to 404 ng/mL in 2 months. Computed tomography, magnetic resonance imaging, and angiography revealed a liver tumor in segment 7 without early enhancement. With a diagnosis of recurrent HCC, partial hepatic resection was performed. The resected specimens revealed no HCC macroscopically, and pathological examination revealed only a small area with cell dysplasia. The patient remains well with normal serum AFP and protein induced by vitamin K absence or antagonist-II (PIVKA-II) levels for 29 months after the third hepatic resection without recurrence of HCC. We describe a case of spontaneous pathological complete regression of HCC following decrement of elevated serum AFP. Further studies are needed to identify the mechanism(s) of spontaneous regression of HCC.