Abstract
We report a patient with metachronous bilateral malignant melanomas in the nasal cavity and paranasal sinuses that were attributed to submandibular lymph node metastasis.
A 65-year-old female visited our hospital with a left submandibular mass. She was diagnosed as having a left submandibular gland tumor, and surgery was performed. The histological diagnosis was lymph node metastasis from a malignant melanoma. Neither the primary lesion nor other metastatic lesions were detectable by CT, MRI, or FDG-PET. However, visual examination confirmed the presence of a black mass (approximately 1 mm in diameter) at the anterior edge of the left inferior nasal concha and blackish brown pigmentation of the mucosa of the left common nasal meatus tectorium. The primary origin was considered to be the nasal cavity. Endoscopic tumor resection and left neck dissection were performed through a left lateral rhinotomy incision. Histopathological examination revealed multicentric melanoma at the anterior edge of the left inferior nasal concha and mucosal interstitium of the maxillary sinus. No metastasis was detected in the dissected lymph nodes. The patient was diagnosed as having malignant melanoma, pT3pN1M0, stage IVA. Three cycles of adjuvant chemotherapy (DAV therapy: DTIC, ACNU, VCR) were administered. Sixty-two months after the surgery, a black lesion appeared in the right olfactory cleft. Biopsy was performed, and recurrence of malignant melanoma was confirmed. The tumor was endoscopically resected through a right lateral rhinotomy incision. Melanoma lesions were observed in the right anterior ethmoid and right sphenoid sinuses. Three cycles of adjuvant chemotherapy (DAC-Tam therapy: DTIC, ACNU, CDDP, TAM) were again administered. At present, 89 months after the surgery, the patient remains free of recurrence or metastasis.
Malignant melanomas, even small ones, can metastasize early to the lymph nodes. Since they are sometimes multicentric, an examination of the entire body and extensive resection with an adequate safety margin, such as total resection of the sinonasal mucosa, are necessary.
