Although several clinicopathological studies of
malignant melanoma of the nasal cavity have been reported, there are no studies of the expression and gene mutation of KIT and
platelet derived growth factor receptor-α (PDGFRA) in
melanoma of the nasal cavity. A 92-year-old Japanese woman consulted to our hospital because of right
nasal obstruction and
epistaxis. Physical examination and imaging modalities showed a
tumor of the right nasal cavity. A biopsy was taken, and it showed malignant epithelioid cells with
melanin deposition. Immunohistochemically, the
tumor was positive for
S100 protein, HMB45, p53, Ki-67 (labeling=20%), KIT and PDGFRA. The
tumor was negative for cytokeratins (AE1/3 and
CAM5.2). A genetic analysis using PCR-direct sequencing revealed no mutation of KIT gene (exons 9, 11, 13, and 17) or the PDGFRA gene (exons 12 and 18). The pathological diagnosis was primary
malignant melanoma of the nasal cavity. The
tumor was reduced in size by local resection and
chemotherapy (Darthmose regimen:
dacarbazine,
carmustine, cisplatine, and
tamoxifen), and the patient is now alive and free from
metastasis 9 months after the first manifestation. In conclusion, the author reported a case of
melanoma of the nasal cavity expressing KIT and PDGFRA without gene mutations of KIT and PDGFRA.