A Giant Dendritic Fibromyxolipoma in the Right Thorax: A Rare Entity.

Dendritic fibromyxolipoma (DFML) is an uncommon benign tumor. We report the first DFML in the right thorax of a child. An 11-year-old girl was admitted because of a giant tumor in the right thorax. An enhanced chest CT scan indicated a thoracic mass with mild enhancement. Thoracoscopic biopsy revealed that the tumor was composed of stellate and spindle cells embedded within abundant myxoid stroma. Additionally, mature adipocytes, cytoplasmic dendritic processes, short strands of keloidal-type collagen, and plexiform blood vessels were observed. Immunohistochemical staining indicated positive for CD34 and BCL-2. DDIT3 alteration or MDM2 amplification were not observed. The diagnosis of DFML was considered, and complete tumorectomy was performed. In conclusion, definite diagnosis of DFML should be made according to the pathologic features. Accurate diagnosis is crucial to avoid overtreatment because DFML potentially can be mistaken for more aggressive neoplasms.