大胸筋腱に生じた石灰性腱炎の1例

A case of calcific tendinitis of the pectoralis major tendon

石灰性腱炎（calcific tendinitis）は，腱に塩基性リン酸カルシウム（basic calcium phosphate：BCP）が沈着することにより急性の疼痛・可動域制限をきたす炎症性疾患である^1）。肩関節周囲，特に棘上筋腱に好発し，そのため石灰化腱板炎の名前で広く知られているが，肩関節に限局した疾患ではなく，股関節，膝関節，肘関節など，全身の様々な筋の腱で発症しうる。

We report a case of calcific tendinitis at the pectoralis major insertion with humerus bone lesion. Calcific tendinitis can be complicated by bone lesions, including cortical erosions and subcortical or intramedullary calcification. These lesions sometimes mimic bone tumors. Calcific tendinitis has specific imaging findings such as “comet-tail appearance” which represents calcification at tendon, and CT is highly sensitive in detecting these findings. MRI is less sensitive in detecting pale calcification, but can detect changes in the T2WI signal of the tendon and contrast effects. Knowing bone lesions and specific imaging findings of calcific tendinitis can help to differentiate from bone tumors.