Calcifying tendinitis of the gluteus maximus tendon presenting as a tumor-like lesion: a case series

Introduction Severe pain and limitation of function of the hip joint can be a challenge for the clinician. Unawareness of the presence of calcifying tendinitis in hip joint muscle and tendeons can lead to unnucessary (invasive) diagnostics and potentially harmful treatment. Case presentation We present two cases of calcifying tendinitis of the gluteus maximus muscle. The patients presented with excruciating pain at the lateral part of the thigh with limitation of daily activities. In one case, a caucasian male 44 years of age, the diagnosis was based on the characteristic radiologic appearance of a calcification in the tendon of the gluteus maximus muscle without any other findings. In the other case, a caucasian male 45 years of age, there was also considerable cortical erosion at the insertion of the muscle, which led to the suspicion of malignant disease. Further radiologic investigation and a needle biopsy narrowed the diagnosis down to calcifying tendinitis. Both patients revored fully with conservative treatment.