primary atypical lipomatous tumor of the orbit:a case report

Purpose: to describe a case of primary atypical orbital lipomatous tumor (alt). case report: a 35‑year‑old man presented with a two‑month history of left eye proptosis and vertical diplopia. his visual acuity was 20/30 od and 20/60 os. external examination showed proptosis and downward displacement of the left eye with mild lid erythema. extraocular movements were reduced in the left eye, with 10% and 70% motility in upgaze and abduction/adduction, respectively. imaging showed a mass (22 × 16 × 46 mm) in the superior left orbit that infiltrated the orbital fat and the superior rectus muscle. a biopsy of the mass showed mature adipose tissue intermingled with fibrous zones of hyperchromatic stromal cells with nuclear atypia. fluorescence in situ hybridization analysis demonstrated positive amplification for mdm2/cep12. the mdm2 to cep12 ratio was 5:7. a diagnosis of alt was confirmed. an orbital exenteration was recommended, which the patient declined. conclusion: although rare, the differential for unilateral proptosis with or without diplopia should include orbital liposarcomas including the alt subtype. imaging, biopsy, staining, and/or fish analysis for proto‑oncogenes can assist with diagnosis and staging, while the standard treatment is exenteration