Granular cell tumors: Review of the parameters determining possible malignancy.

The granular cell tumor (GCT) is normally benign in behavior, but occasionally surprises us with local aggressiveness, and in 2% of cases with distant dissemination. Diagnosis of proven malignancy can only be confirmed by the presence of metastasis. We revised the parameters which give rise to a GCT being considered to have malignant behavior in the absence of metastasis, basing our account on a clinical case.