Summary Genuine granuloma formation following implantation of injectable dermal fillers is a rare complication, with incidences ranging from one in 100 patients (1 percent) to one in 5000 (0.02 percent). Foreign body granulomas occur several months to years after injection at all implantation sites at the same time. Without treatment, they may grow to the size of beans, remain virtually unchanged for some years, and then resolve spontaneously. Three clinical and histologic types of foreign body granulomas can be distinguished: 1. Cystic granulomas (synonyms: inflammatory, palisading, collagenolytic): these are caused mainly by injected biological gels such as collagens and hyaluronic acids. Their clinical signs are fluctuation (sterile abscess), extreme redness, and induration. Cystic granulomas are small and superficial, occur within the first year, and disappear spontaneously within another year. They are surrounded by a significant number of giant cells. 2. Edematous granulomas (synonym: lipogranuloma): these are caused by artificial fluids such as silicone and polyacrylamides. They appear suddenly years after injection with extensive swelling and are surrounded and infiltrated by mononuclear and inflammatory cells. 3. Sclerosing granulomas (synonyms: sarcoidal and xanthelasmic): these are caused by particulate injectables composed of polymethylmethacrylate, polylactic acid, hydroxyethylmethacrylate, calcium-hydroxylapatite, or dextran microspheres. Sclerosing granulomas occur generally 6 months to 3 years after implantation and are visible, often bluish confined nodules. Histologically, the implant is infiltrated by many macrophages and giant cells, fibroblasts, and collagen fibers but few inflammatory cells. Permanent implants are not characterized by a higher rate of foreign body granuloma per se than temporary implants; however, their clinical appearance is more pronounced and their persistence longer if not treated adequately. (Plast.

Summary: All fillers are associated with the risk of both early and late complications. Early side effects such as swelling, redness, and bruising occur after intradermal or subdermal injections. The patient has to be aware of and accept these risks. Adverse events that last longer than 2 weeks can be attributable to technical shortcomings (e.g., too superficial an implantation of a long-lasting filler substance). Such adverse events can be treated with intradermal 5-fluorouracil, steroid injections, vascular lasers, or intense pulsed light, and later with dermabrasion or shaving. Late adverse events also include immunologic phenomena such as late-onset allergy and nonallergic foreign body granuloma. Both react well to intralesional steroid injections, which often have to be repeated to establish the right dose. Surgical excisions shall remain the last option and are indicated for hard lumps in the lips and visible hard nodules or hard granuloma in the subcutaneous fat. (Plast. Reconstr. Surg. 118 (Suppl.): 92S, 2006.) The aesthetic benefit the patient achieves with temporary fillers is 90 percent technique and 10 percent substance. With permanent fillers, it's 99 percent technique.Jean Carruthers 1 A ll injectable dermal fillers can cause complications. Late side effects can be divided into those caused by insufficient training or technical errors during injection and those caused by immunologic (allergic and nonallergic) reactions to the injected substance. In the case of late, nonallergic reactions, the pathologic substratum differs from injectable to injectable but can always be classified into one of three distinct forms of foreign body granuloma.2 The histologic reaction is always similar, 3 and the trigger for this sudden stimulation of macrophages might be a systemic infection of the patient.