Case of preauricular primary malignant melanoma treated with preoperative dabrafenib/trametinib

Abstract

A 41－year－old Japanese woman was referred to the Department of Otorhinolaryngology at our hospital with a diagnosis of right parotid tumor and cervical lymph node metastasis. The patient underwent right parotidectomy and right cervical lymph node dissection, and was referred to our department because of a histopathological diagnosis of malignant melanoma. A black nodule observed on the right preauricular area was excised as the primary melanoma. Two months after surgery, metastases were observed by computed tomography, which revealed the presence of an enlarged right axillary lymph node, a right breast subcutaneous nodule, and a right lower abdominal subcutaneous nodule. The right lower abdominal subcutaneous nodule was excised, and histopathological examination revealed metastatic melanoma. Although we planned to perform a right axillary dissection and partial right mastectomy, the operation was postponed due to the outbreak of Coronavirus Disease 2019 . Therefore, the patient was treated with dabrafenib/trametinib as for unresectable melanoma. Two months after the initiation of dabrafenib/trametinib, the right enlarged axillary lymph node and breast subcutaneous nodule disappeared. Four months after the initiation of dabrafenib/trametinib, the patient finally underwent a right axillary dissection and right partial mastectomy ; histopathological findings showed no residual melanoma. To summarize, the patient was successfully treated with dabrafenib/trametinib as neoadjuvant therapy. The neoadjuvant regimen of dabrafenib/trametinib, although uncovered by insurance in Japan, may be a useful therapeutic option for resectable advanced melanoma. [Skin Cancer (Japan) 2021 ; 36 : 203－211]