Department of Orthopaedics and Traumatology, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, 200032, China.
Oxford University Clinical Academic Graduate School, Medical Sciences Division, University of Oxford, Oxford, OX3 9DU, UK.
BMC Musculoskelet Disord. 2020 Mar 12;21(1):161. doi: 10.1186/s12891-020-3168-x.
Bizarre parosteal osteochondromatous proliferation (BPOP) is a relatively rare benign extraperiosteal osteochondroma-like proliferative lesion that shares similarities with malignant tumours in terms of morphology. The aetiology of BPOP has yet to be determined and there are no previous reports of BPOP associated with fracture.
A 57-year-old woman presented with a one-month history of pain and swelling in her right foot, which were worsened by activity and improved with rest. Physical examination revealed a hard, non-mobile mass measuring 1.5 cm × 1.5 cm on the dorsal aspect of the third metatarsal of the right foot. There was overlying erythema and tenderness on palpation. Computed tomography (CT) of the right foot demonstrated a fracture of the neck of the third metatarsal, osteolysis at the fracture site and soft tissue swelling. Bone scintigraphy revealed increased tracer uptake suggesting abnormal bone metabolism at the neck of the third metatarsal. Surgical excision of the lesion was performed. Histopathology and immunohistochemistry confirmed the diagnosis of BPOP.
BPOP is a rare benign lesion that is commonly misdiagnosed. Differential diagnosis is mainly achieved through imaging and histopathological assessment.
奇异骨旁骨软骨瘤性增殖（BPOP）是一种相对罕见的良性骨外骨软骨瘤样增殖性病变，其形态与恶性肿瘤相似。BPOP 的病因尚未确定，以前也没有与骨折相关的 BPOP 报告。
一名 57 岁女性因右脚疼痛和肿胀一个月就诊，活动时加重，休息时缓解。体格检查发现右脚第三跖骨背侧有一个 1.5cm×1.5cm 的硬而不可移动的肿块。触诊时有红斑和压痛。右脚 CT 显示第三跖骨颈骨折、骨折部位骨质溶解和软组织肿胀。骨闪烁扫描显示第三跖骨颈摄取示踪剂增加，提示骨代谢异常。对病变进行了手术切除。组织病理学和免疫组织化学检查证实了 BPOP 的诊断。
BPOP 是一种罕见的良性病变，常被误诊。鉴别诊断主要通过影像学和组织病理学评估来实现。
