Malignant transformation of a solitary fibrous tumor of the liver and intractable hypoglycemia.

Sarcomas of the liver are rare. We report a case of intractable hypoglycemia secondary to a solitary fibrous tumor that underwent malignant transformation into a fibrosarcoma. A 70-year-old man presented with a hepatic mass and tumor-associated hypoglycemia which was resistant to medical management. Blood tests were remarkable only for elevated serum insulin-like growth factor (IGF)-2. The hypoglycemia resolved following resection of a solitary fibrous tumor surrounded by a high-grade fibrosarcoma. Real time reverse transcriptase polymerase chain reaction (RT-PCR) measured elevated levels of IGF2 mRNA in both the solitary fibrous tumor and the fibrosarcoma. Immunoblotting demonstrated a series of bands in the size range of pro-IGF2. Unfortunately, disseminated metastases developed 1 year later, concurrent with a recurrence of hypoglycemia, marked again by elevation of serum IGF2. Solitary fibrous tumors of the liver have a real risk of malignant transformation. The severity of the tumor-associated hypoglycemia may parallel the tumor burden and activity. The syndrome is the systemic effect of IGF2 secreted by the tumor. Surgery can treat the hypoglycemia syndrome and the underlying malignancy.