Spontaneous regression of lymphovascular invasion and metastasis of malignant melanoma: ultrasound findings

Abstract

This report presents a case of malignant melanoma in a 40-year-old male who underwent resection of the tumor in his right ankle. Eleven months after the resection, a subcutaneous mass was observed on his right femur. Ultrasound examination revealed a hypoechoic tubular structure in the right thigh, with a small amount of blood flow in the lesion. Using ultrasound and fine-needle aspiration, the patient was diagnosed with metastasis and lymphovascular invasion of malignant melanoma. Treatment with an immune checkpoint inhibitor was originally scheduled, but the lesion disappeared spontaneously after the fine-needle aspiration.

Case Details

Disease Location

Subcutaneous tissue

Personal Characteristics

40-year-old man with malignant melanoma underwent resection of the tumor on his right ankle

Clinical Characteristics

Eleven months later, a subcutaneous mass was revealed in the middle of his right femur. Ultrasound examination showed a hypoechoic tubular structure in the subcutaneous layer of the right thigh. A lymphovascular invasion of malignant melanoma was suspected. The fine needle aspiration (fna) cytology from this lesion showed atypical spindle-shaped and/or round cells with fine brown granules, indicating the presence of melanie resulting in the diagnosis of malignant melanoma. Finally, the patient was diagnosed with metastasis and lymphovascular invasion of malignant melanoma.

Remission Characteristics

The lesion disappeared after fna.

Treatment & Mechanisms

Proposed Remission Mechanisms

Inflammation could have been triggered by the puncture for fna, leading to tumor regression

Clinical Treatment

Biopsy