Unique cytological features and chromosome aberrations in chondroid lipoma- A case report based on fine-needle aspiration cytology, histopathology, electron microscopy, chromosome banding, and molecular cytogenetics

Chondroid lipoma is a rare, benign tumor that may mimic soft-tissue sarcoma clinically. Its histopathologic features may resemble hibernoma, myxoid li posarcoma, myxoid chondrosarcoma, and other lipomatous or chondroid neoplas ms. In this study, a chondroid lipoma was analyzed by fine-needle aspiratio n cytology, histopathology, electron microscopy, chromosome banding, and me taphase fluorescence in situ hybridization. The results demonstrate that ch ondroid lipoma exhibits a characteristic pattern by fine-needle aspiration cytology, including a mixture of benign adipose tissue with lipoblastlike c ells, and chondroblastlike cells with a fibrochondroid matrix. Cytogenetica lly, a three-way rearrangement between chromosomes 1, 2, and 5 was found, t ogether with an 11;16 translocation with a breakpoint in 11q13, approximate ly 1 Mb proximal to the MEN1 region shown to be rearranged frequently in hi bernoma. The presence of a karyotype of low complexity, but without any of the genetic aberrations characteristic for other types of soft-tissue tumor s, indicate that chondroid lipoma develops along a unique pathogenetic path way.