Adverse reactions to injectable soft tissue fillers.

In recent years, injections with filler agents are often used for wrinkle-treatment and soft tissue augmentation by dermatologists and plastic surgeons. Unfortunately, the ideal filler has not yet been discovered and all of them may induce adverse reactions. Quickly biodegradable or resorbable agents may induce severe complications, but they will normally disappear spontaneously in a few months. Slowly biodegradable or nonresorbable fillers may give rise to severe reactions that show little or no tendency to spontaneous improvement. They may appear several years after the injection, when the patient does not remember which product was injected, and treatment is often insufficient. In this review, we discuss the most commonly used fillers, their most frequent adverse reactions as well as the characteristic histopathologic findings that allow the identification of the injected filler agent. In conclusion, histopathologic study remains as the gold standard technique to identify the responsible filler.

Foreign body granuloma due to Matridex injection for cosmetic purposes.

A new resorbable filler, Matridex, became commercially available during the last years with scarce evidence regarding side effects. A 43-year-old woman complained of multiple, painful, reddish, nonulcerated, hard nodules on both cheeks and periocular regions. Four weeks before, she had been injected by a general practitioner with Matridex for aesthetic purposes to correct wrinkles in the same areas of the nodular eruption. Histopathology showed a diffuse suppurative granulomatous reaction with the presence of multinucleate giant cells and many neutrophils involving the entire dermis. No areas of caseation were observed. The inflammatory granulomatous reaction surrounded 2 different types of nonpolarizing, bluish, exogenous material: one arranged in filamentous structures and the second composed by large spherical particles. All nodules were incised and drained; the patient received systemic antibiotic treatment for 2 consecutive weeks. The nodules progressively regressed and almost complete resolution was seen after 6 months. Matridex is a new resorbable filler constituted by a mixture of nonanimal-stabilized hyaluronic acid (HA), cross-linked HA, and dextranomer microspheres. Foreign body reactions have been described in association with other HA fillers, but a granulomatous reaction after the injection of Matridex has not been reported yet. Interestingly, in our patient, we were able to identify both fragments of HA: the filamentous particles and the spherical particles of dextranomer microspheres within the infiltrate, these last giving a characteristic and recognizable appearance to the histopathological picture.