Injection granulomas are one of the most common findings in the gluteal region. They can be single or multiple, unilateral or bilateral, and vary in size.

Post injection, fat necrosis and dystrophic calcification take place, resulting in calcified granulomas.

Subcutaneous (intra-fat) granuloma is much more common than intramuscular granuloma (93% vs 7%). This is due to the fact that buttock subcutaneous fat thickness (5.7 +/- 1.8 cm for female vs 4.4 +/- 1.7 cm for male) exceeds the length of the most commonly used needle for intramuscular buttock injection (3.8 cm).