Retroperitoneal and deep-seated lipoblastoma: diagnosis by CT scan and fine-needle aspiration biopsy.

Lipoblastomas are most commonly superficially-located tumors. Our experience with three examples of deep-seated lipoblastomas is reported. The CT scans of all cases showed low-attenuation densities (less than 0 Hansfield units), strongly suggesting fatty composition. Fine-needle aspiration biopsy (FNAB) smears contained uni- and multivacuolated lipoblasts, myxoid areas, and a plexiform capillary network. The combination of CT scan and FNAB findings seems to be enough for definitive preoperative diagnosis of lipoblastoma, allowing differential diagnosis with other deep-seated tumors.