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.

中文翻译：

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zar骨疲劳性骨折同时发生怪异的骨旁骨软骨瘤增生

奇异的骨膜旁骨软骨瘤增生（BPOP）是一种相对罕见的良性骨膜外骨软骨瘤样增生性病变，在形态学上与恶性肿瘤相似。BPOP的病因尚未确定，BPOP与骨折相关的报道尚无报道。一名57岁的女性右脚疼痛和肿胀已有1个月的病史，运动后病情恶化，休息后病情好转。体格检查发现右脚第三meta骨的背面长有一个1.5厘米×1.5厘米的坚硬，不可移动的肿块。触诊时有红斑和压痛。右脚的计算机断层扫描（CT）显示第三third骨的颈部骨折，骨折部位的骨溶解和软组织肿胀。骨闪烁显像显示示踪剂摄取增加，表明在第三meta骨颈部异常骨代谢。进行手术切除病变。组织病理学和免疫组化证实了BPOP的诊断。BPOP是一种罕见的良性病变，通常会被误诊。鉴别诊断主要通过成像和组织病理学评估来实现。