PET detection of solitary distant skeletal muscle metastasis of esophageal adenocarcinoma.

A 67-year-old man with progressive dysphagia was recently diagnosed with a gastroesophageal junction adenocarcinoma. Contrast-enhanced CT scans of the abdomen and pelvis reported a large GE junction tumor without evidence of metastatic disease. FDG positron emission tomography revealed intense tracer accumulation in the soft tissue mass at the GE junction consistent with the primary neoplasm. In addition, PET scan also identified a solitary focus of intense FDG accumulation at the musculotendinous junction of the right gluteus minimus muscle. Subsequent MRI demonstrated mild enhancement and could not differentiate between tumor versus inflammation. Needle biopsy was performed and confirmed metastatic esophageal adenocarcinoma. A case of skeletal muscle metastases from late-stage (IV) gastroesophageal adenocarcinoma was previously reported. However, a solitary metastasis to a distant skeletal muscle without evidence of other lymphatic and hematogenous metastasis is quite unusual. The case supports the previous report that PET is superior in detecting distant metastases for initial staging of esophageal carcinoma over CT.