Atypical spindle cell lipomatous tumour presenting as a large retroperitoneal mass - a case report and review of the literature.

Atypical spindle cell lipomatous tumour (ASCLT) is a benign neoplasm that presents a variable proportion of atypical spindle and adipocytic cells, frequently expressing CD34, and embedded in myxoid or collagenous matrix. An important feature is a constant lack of either MDM2 or CDK4 amplification. It typically arises in the extremities.