Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Sarcomatoid hepatocellular carcinoma (HCC) is a very rare histologic variant of HCC. The characteristic of skeletal metastatic sarcomatoid hepatocellular carcinoma has never been reported. We reported a patient with sarcomatoid hepatocellular carcinoma pelvic metastasis who presented with huge pelvic metastasis that had relatively small osteolytic lesion centrally located accompanied by huge bipeduncular invasive expansile lesions into surrounding soft tissue. The lesion showed almost non-isotope uptake in 99m Tc-methylene diphosphonate bone scintigraphy study. He underwent radiotherapy and tumor excision but the tumor rapidly recurred. In addition, serum α-fetoprotein level was never elevated beyond normal limit (< 20 ng/mL) through the whole course of treatment. We considered sarcomatoid hepatocellular carcinoma bone metastasis a highly aggressive lesion with unusual metastatic pattern. Surgical treatment with adequate safe margin in such a huge tumor with hypervascularity and extensive invasion in the pelvis was difficult; and radiotherapy maybe refractory regarding the sarcomatous nature. Therefore, debulking operation with local symptoms control may provide a better quality of life. And the clinical course suggests sarcomatoid hepatocellular carcinoma is derived from the transition of an ordinary hepatocellular carcinoma. IntroductionSarcomatoid hepatocellular carcinoma (HCC) is a very rare histologic variant of HCC with an incidence of 1.8% in surgically resected cases and 3.9% to 9.4% in autopsied cases [1][2][3][4]. Although sarcomatous transformation of HCC had been discussed in a few reports [3,5]; it was never been reported in patients with bone metastasis.The skeletal metastasis of sarcomatoid HCC have specific features of expansile, destructive nature, accompanied by large, bulky soft tissue masses; and these lesions often showed non-isotope uptake in 99m Tc-methylene diphosphonate (MDP) bone scintigraphy (BS) study [4,[6][7][8].We report a patient with sarcomatoid HCC pelvic metastasis. The patient presented with huge pelvic metastasis that had relatively small osteolytic lesion centrally located accompanied by huge bipeduncular invasive expansile lesions into surrounding soft tissue. He underwent radiotherapy and tumor excision. Unfortunately, the tumor rapidly recurred in short period. On the other hand, serum α-fetoprotein (AFP) level was never

High FN rate of Tc-99m MDP BS in detecting metastatic bone lesions for HCC patients was observed. In our opinion, careful history taking, meticulous examination, and a high index of suspicion are important for HCC patients with unexplained progressive pain in the musculoskeletal system. Even with negative results from Tc-99m MDP BS, the possibility of skeletal metastases cannot be indiscriminately excluded.

No abstract