Figure 2: (a) Fine-needle aspiration cytology smears are cellular with sheets of large, round cells with focal rosette formation (Giemsa, ×40), (b) focal presence of neuropil amidst the large cells (Giemsa, ×400), (c) tumor cells show strong immunopositivity for synaptophysin (immunocytochemistry, 3,3'-diaminobenzidine as chromogen, ×100), (d) biopsy shows features of differentiating neuroblastoma (H and E, ×400)