In some patients, granulomatous reactions around foreign-bodies with FDG-PET positivity may be misinterpreted as malignancy. We report a case of a 31-year-old man diagnosed with testicular germinal tumor with retroperitoneal and left supraclavicular metastases. The diagnosis was based on left supraclavicular lymph node biopsy. Restaging examinations after orchiectomy and chemotherapy showed normalization of tumor markers and significant regression of the retroperitoneal infiltrate, however, with a residual FDG-PET positive lesion in the left supraclavicular fossa. The etiology behind this infiltration was revealed by a repeated histological examination, which surprisingly showed a foreign-body granuloma formation around a cotton pad left after the first surgery.