Fine-needle aspiration of lipoblastoma: Cytological, molecular, and clinical features.

Background: Lipoblastomas are rare, benign adipocytic tumors that present mostly during infancy. In about 70% of cases, these tumors carry abnormalities in chromosome 8, mainly leading to rearrangements of the PLAG1 gene.

Methods: We report a series of histologically proven lipoblastomas with previous fine-needle aspiration (FNA) cytology from 9 patients (n = 10 samples) and describe their clinical, cytological, and molecular features.

Results: Our cohort included 5 boys and 4 girls (median age, 2.5 years [range, 10 months to 13 years]) who presented with soft tissue masses in the thorax (n = 3), abdomen (n = 2), axilla (n = 2), and thigh (n = 2). In 1 patient, the FNA diagnosis was inconclusive due to hypocellularity, and in another patient a diagnosis of benign lipomatous tumor was made. In the remaining 8 samples (one of which confirmed relapse), a correct preoperative FNA diagnosis was rendered. Smears were hypo- to moderately cellular and contained fragments of mature adipose tissue with thin branching vessels admixed with some lipoblasts in a myxoid matrix. Spindle cells and naked oval nuclei with no atypia were observed in the background. Of the 4 patients tested for PLAG1 rearrangement using FISH probes, 3 harbored this alteration (1 was made on a FNA smear and 1 was made in a tumor imprint). All the patients are alive and well, except for 1 patient with a retroperitoneal tumor who, after an initial incomplete excision, died of local disease progression.

Conclusion: FNA, especially if used together with molecular biology techniques (eg, PLAG1 FISH analysis), is a reliable and accurate diagnostic tool. Cancer Cytopathol 2017;125:934-9. © 2017 American Cancer Society.