RESUMEN
Calcinosis is defined as a biomineralization occurring in soft tissues leading to ectopic calcification. Isolated and localised calcification in a muscle is rare, and it is called calcinosis circumscripta in opposition to calcinosis universalis wich is seen in juvenile dermatomyositis and polymyositis. According to laboratory findings and clinical history, calcinosis circumscripta can be metastatic, dystrophic or idiopathic. Masseter muscle is rarely involved. Pre-operative diagnosis of masseter idiopathic calcinosis is a challenge because of many differential diagnosis. Here, we report a case of 22 years old women presented with swelling over left middle third of her face. Clinical history, morphologic and laboratory examinations helped considering such a rare diagnosis.