Fine-needle aspiration cytology of lipoblastoma: a report of two cases

Lipoblastoma is an uncommon lipomatous tumor that typically occurs in infants and children. It may present as a single subcutaneous nodule or with multiple lesions (lipoblastomatosis). We describe fine-needle aspiration (FNA) cytologic features of two cases that presented as a subcutaneous lump in the scapular area and as a deeply located mass in the left arm. Smears showed fragments of adipose tissue that consisted of numerous vacuolated adipocytes with few stroma. Nuclei were small and located centrically, without indentations. Myxoid stromal material was a remarkable finding in one case. Both cases showed small delicate vessels, mainly in relation with the myxoid material. No necrosis, atypia, or mitotic figures were present. Cytologic features were characteristic enough to permit a specific diagnosis (adipose tumor suggestive of lipoblastoma). The differential diagnosis should consider lipoma with regressive changes, well-differentiated and mixoid liposarcoma. In addition to cytologic features, the patient's age is very useful for differentiation.