骨転移が疑われたinsufficiency fractureの8例

Insufficiency Fracture of the Pelvic Girdle Initially Suspected of Being a Skeletal Metastasis. Report of 8 Cases

　骨転移が疑われて紹介されたinsufficiency fractureの8例を経験した．平均年齢は65.6歳(38～76歳)で全例女性であった．主訴は全例腰部から殿部にかけての疼痛であり，3例はさらに鼠径部痛も認めた．骨の脆弱性を来した原因は放射線障害3例，薬剤性骨粗鬆症3例，老人性骨粗鬆症2例であった．1例を除き画像で診断可能であり，骨粗鬆症と同様の治療で全例軽快した．特徴的な画像を理解しておくとともに，治療の影響によってinsufficiency fractureを起こしやすい癌腫があることを認識しておくことが重要である．

　Insufficiency fracture (IF) is a rare stress fracture that occurs in patients with weak bones.　We report eight cases in which the patient was initially suspected of having a skeletal metastasis, but was later diagnosed with an insufficiency fracture of the pelvis.　All of the patients were female, and their mean age was 65.6 years (range：38 to 76 years).　All of the patients presented with low back and/or buttock pain, and three patients also experienced groin pain.　The etiology of the bone loss was previous radiotherapy in 3 cases, cancer chemotherapy in 2 cases, corticosteroid therapy for a brain tumor in 1case, and osteoporosis in 2 cases.　In seven patients the diagnosis of stress fracture was made on the basis of the imaging findings alone, but needle biopsy was required in the other patient.　The symptoms of all of the patients were relieved by treatment for osteoporosis.　It is important to be aware of this rare condition and to avoid confusion with skeletal metastasis, especially in patients with a past history of malignancy.