Sakamoto Akio, Ishii Takeaki, Oda Yoshinao, Iwamoto Yukihide
Department of Orthopaedic Surgery, National Hospital Organization Kokura Medical Center, Kitakyushu, Fukuoka, Japan.
J Med Case Rep. 2012 Nov 29;6:407. doi: 10.1186/1752-1947-6-407.
Nonossifying fibroma is a common fibrous bone lesion in children that occurs in the metaphysis of the long bones of the lower extremities. The lesion rarely leads to aneurysmal bone cyst, which is characterized as a blood-filled space.
We present the case of a 13-year-old Japanese boy with a complaint of discomfort in the thigh and a small, well-defined, osteolytic lesion with cortical thinning located in the medullary space of the distal diaphysis of the femur. At 10-month follow-up, the size of the lesion had increased. Gadolinium-enhanced magnetic resonance imaging failed to detect any solid area. Curettage and bone graft were performed and confirmed a blood-filled cystic lesion. The pathological diagnosis of the cyst wall was that of nonossifying fibroma, suggesting aneurysmal bone cyst as a secondary change. An aneurysmal bone cyst is rarely found secondary to nonossifying fibroma, and the diaphyseal location is atypical for nonossifying fibroma, both of which made diagnosis challenging.
The current case is a reminder to clinicians that, although rare, nonossifying fibroma can be associated with aneurysmal bone cyst, and both can occur in the diaphysis of long bones.
非骨化性纤维瘤是儿童常见的纤维性骨病变，发生于下肢长骨的干骺端。该病变很少导致骨囊肿，其特征为充满血液的腔隙。
我们报告一例13岁日本男孩，主诉大腿不适，在股骨远端干骺端髓腔内有一个小的、边界清晰的溶骨性病变，伴有皮质变薄。在10个月的随访中，病变大小增大。钆增强磁共振成像未检测到任何实性区域。进行了刮除术和骨移植，证实为充满血液的囊性病变。囊肿壁的病理诊断为非骨化性纤维瘤，提示骨囊肿为继发性改变。非骨化性纤维瘤继发骨囊肿很少见，且非骨化性纤维瘤的骨干部位不典型，这两者都使得诊断具有挑战性。
本病例提醒临床医生尽管罕见，但非骨化性纤维瘤可与骨囊肿相关，且两者均可发生于长骨骨干。
