Hypoglycemic coma secondary to big insulin-like growth factor II secretion by a giant phyllodes tumor of the breast

Nonislet cell tumor hypoglycemia (NICTH) is uncommon, and has been related to the production of insulin-like growth factor II or its high-molecular-weight precursor (big IGF-II) by the tumor. Cases of NICTH have been related to different tumors, mainly sarcomas. However, only three cases secondary to a phyllodes tumor of the breast (PTB) have been previously reported. We present the clinical course of a woman with a giant PTB, who developed an irreversible hypoglycemic coma secondary to big IGF-II production by the tumor. A brief review of the literature and possible mechanisms of this infrequent condition are also commented.