We report a patient with a nonresectable histologically benign solitary fibrous tumor who suffered from paraneoplastic non-islet cell tumor hypoglycemia (NICTH). Diagnostic workup revealed malignant characteristics in which the tumor showed up as, presumably, false-negative on fluorodeoxyglucose-positron emission tomography (FDG-PET), while being positive on tyrosine-PET. Neoadjuvant treatment, which consisted of combined chemo-radiation and consecutive selective embolization of the tumor feeding vessels, caused such a therapeutic effect, on both NICTH and reduction in tumor volume, that a secondary resection, with the patient in a normoglycemic status, was possible. Our report highlights several important issues in the management of the patient with a nonresectable solitary fibrous tumor with severe episodes of hypoglycemia due to NICTH.