Fig. 3.

a Dental amalgam eliciting a foreign body giant cell reaction. Granulomas composed of histiocytes, giant cells and lymphocytes are present incorporating the black pigmented material (magnification × 100). b Hyaluronic acid foreign body reaction. Pools of homogeneous basophilic material forming cyst-like structures lined by epithelioid histiocytes (magnification × 200). c Calcium hydroxylapatite composed of uniformly sized spherules surrounded by histiocytes and giant cells. An asteroid body is seen (arrow) (magnification × 200). d Poly-l-lactic acid granuloma composed of fusiform, cholesterol cleft-like material within giant cells and surrounded by chronic inflammation. The material are refractile in polarized light (inset) (magnification × 200)