Malignant granular cell tumor of the ulnar nerve with novel cytogenetic and molecular genetic findings

We report an unusual case of ulnar nerve–based malignant granular cell tumor characterized by gains of chromosome 10 and loss of P16 detected by conventional karyotyping and by fluorescence in situ hybridization, respectively, in a 74-year-old male. To our knowledge, these findings have never been reported previously in malignant granular cell tumors.