Ultrasound-guided fine needle aspiration biopsy (FNAB) demonstrating upper distal extremity metastasis of lung adenocarcinoma: a case report and review of the literature

Due to early metastasis and delayed diagnosis, lung cancer is the leading cause of cancer-related deaths. Although the most common metastasis sites are brain, bone, lung, adrenal glands, liver, and extra-thoracic lymph node, soft tissues, such as skeletal muscles, skin, and subcutaneous tissues, can also be undermined. This article aims to report the first case of an asymptomatic radial extensor muscle metastasis generating from a lung adenocarcinoma that was diagnosed by ultrasound-guided fine-needle aspiration biopsy (FNAB).