[Solitary fibrous tumor of the pleura with elevated high-molecular-weight insulin-like growth factor II and hypoglycemia].

Recurrent hypoglycemia occurred in a 58-year-old woman with a solitary fibrous tumor of the pleura and exhibiting CD34 immunopositivity. During episodes of hypoglycemia, serum high-molecular-weight insulin-like growth factor II (big IGF-II) was elevated. After removal of the tumor containing IGF-II, the hypoglycemia and serum big IGF-II disappeared. This was followed by an increase in normal IGF-II. We speculate that the primary cause of hypoglycemia in this patient was the presence of big IGF-II produced by the solitary fibrous tumor of the pleura. To our knowledge, the presence of this type of IGF-II in CD34+ solitary fibrous tumors of the pleura has not been described to date in the literature.