Upfront Skeletal Muscle Metastases from Non-small Cell Lung Carcinoma: Report of an Extremely Rare Occurrence Detected by 18F-Fluorodeoxyglucose Positron Emission Computed Tomography Scan

Adenocarcinoma lung with upfront metastases to skeletal muscle is rarely encountered in clinical practice since skeletal muscles are highly resistant to dissemination from solid organs. Moreover, these muscle metastatic lesions generally present with pain and palpable mass to get detected clinically. However, silent skeletal muscle metastases without any symptoms or signs getting detected by functional imaging with whole body 18F-fluorodeoxyglucose positron emission/computed tomography (18FDG-PET/CT) scan have been scarcely described in literature, while we present such an interesting case in a 45-year-old female. She was diagnosed as a case of biopsy-proven metastatic adenocarcinoma lung after evaluation by 18FDG-PET/CT. Despite treatment with palliative chemoradiotherapy, her disease progressed, and she finally succumbed to her illness. This case is discussed to highlight an unusual scenario we encountered, the clinical course of the disease with its management and overall poor prognosis.