Abstract
We encountered a case of supraclavicular schwannoma requiring differentiation from lymph node metastasis by FDG-PET/CT performed for the preoperative staging of lung cancer. The patient was a 59-year-old man with a 1.7×1.2-cm adenocarcinoma in the anterior segment of the left upper lobe. FDG-PET/CT, performed for preoperative lung cancer staging, showed a high FDG uptake in the primary lung lesion and a 2-cm round mass in the right supraclavicular fossa. Although the possibility of lymph node metastasis could not be excluded, skip metastases were considered unlikely for epidemiological reasons, and surgery was performed. No lymph node metastasis was observed. Postoperative contrast-enhanced, T2-weighted MRI showed a hyperintense, ring-enhancing supra-clavicular mass suggestive of schwannoma. Biopsy of the mass was performed, and subsequent immunostaining revealed S-100-positive, spindle-shaped tumor cells, leading to a definitive diagnosis of benign schwannoma. Schwannomas, even if benign, exhibit high-level FDG uptake, and are sometimes difficult to differentiate from lymph nodes, depending on their size and location. Therefore, supraclavicular lesions in lung cancer patients should be carefully examined.
