Histopathological and MRI characteristics of facial unidentified filling objects / 中华医学美学美容杂志

ABSTRACT

Objective:Unidentified filling objects (UFO) can cause adverse results including infections, overfilling, asymmetry, foreign body granulomas, dislocation or psychological panic. To remove UFO accurately, it is important to locate and identify the injected substances preoperatively. This study investigated the viability of using MRI to correctly locate and identify injected substances by relating MRI to gross and pathological microscopic examination.Methods:Eighty-two facial UFO patients from 2013 to 2017 were studied by the experts of the Department of Image, Xinhua Hospital of Dalian University. Five of the patients were male and seventy-seven were female. The age ranged from 17 to 58 years with average 29.4 years. They came to our hospital for removal of UFO after they had facial injective fillers in the illegal medial offices. The injected sites involved in the forehead, temple, malar, cheek, nose, nasolabial folds, and chin. All the patients＇ faces were examined with MRI preoperatively, using T1W, T2W and fat-suppressed sequences. Based on the guides of MRI, UFOs were removed with their capsules by open approach. Samples were recorded with digital pictures and then were fixed in 10% formalin solution for microscopic examination of HE stained slices.Results:Based on MRI, gross and microscopic examination, UFO were classified into 3 types, gel-like fillers, solid particles, and growth factors. Gel-like fillers appeared strongly hyperintense on T2 W and STIR sequences and hypointense on T1 W sequences. Grossly, they looked like gruel covered by altered soft tissue. Under the light microscope, many pieces of blue-stained material were dispersed in subcutaneous tissue infiltrated with a large number of mononuclear cells and foreign-body giant cells. Solid particles had low to intermediate signal intensity on T1 W and T2 W images. Grossly, they were like sand merging in soft tissue. The biopsy showed crowed bubbles surrounded by tissue filled with a large number of mononuclear cells and foreign-body giant cells. For growth factors affected tissue, it was hard to differentiate between normal and abnormal on MRI. The affected tissue appeared as somehow hypointense on T1 W sequences and hyperintense on T2 W fat suppressed sequences. During the operation, the affected region was easy bleeding and full of fibrofatty tissue. Under the microscope, there were increased small blood vessels and collagens.Conclusions:Based on MRI, gross and microscopic examination, UFO can be classified into 3 types, gel-like fillers, solid particles, and growth factors. MRI is very important for doctors to assess the patient＇s conditions and make the plan of operation. MRI is also useful for doctors to locate UFO and understand the relationship between UFO and their nearby organs.