Misdiagnosis and treatment of a case of malignant melanoma found in an axillary mass: case report and review

Abstract

Background Malignant melanoma (MM) is a highly dangerous, potentially fatal tumor originating from melanocytes in the neural crest. It most often occurs in the skin, and regional lymph nodes (inguinal, axillary, cervical, and others) can metastasize at an early stage. Malignant tumors not involving the hematopoietic system initially appear as axillary masses, constituting a unique clinical manifestation. Moreover, MM in an axillary mass is difficult to diagnose preoperatively and is easily misidentified. Case presentation: Here, we report on a 62-year-old woman with MM occurring within an axillary mass; it was initially misdiagnosed as synovial sarcoma and fibrosarcoma. Under general anesthesia, the patient underwent radical surgery of a right axillary lymph node; she then received six cycles of chemotherapy. About 14 months later, the lesion recurred and metastasized to the chest wall and breast skin. After biopsy of the skin nodules on the chest wall as well as examination by immunohistochemistry(IHC) and gene detection, the lesion was confirmed to be a MM. Finally, after two cycles of targeted drug treatment, the lesions in the armpit, chest wall, and breast skin disappeared. Conclusion MM is an often lethal, highly malignant, easily misdiagnosed form of cancer that requires careful study, following its clinical course, and scrutinizing the findings from imaging, pathology, immunohistochemistry, and gene detection.