Fig. 4

A 23-year-old male with non-seminomatous testicular cancer, treated with orchidectomy followed by chemotherapy, presented with suspicious retroperitoneal lymphadenopathy on CT and underwent an FDG PET scan (Image A). The axial (a, d), coronal (b, e), and sagittal (c, f) views show enlarged hypoattenuating retroperitoneal lesions with no metabolic activity (red arrow). Serial CT scans demonstrated ongoing enlargement of these lesions. Ten months later, a follow-up PET scan (Image B) revealed further enlargement of the hypoattenuating retroperitoneal lesions with interval development of peripheral metabolic activity (images g-l, green arow), highly suggestive of nodal metastases. Subsequent nodal dissection confirmed the presence of nodal metastases on histopathology