Bizarre parosteal osteochondromatous proliferation | |
---|---|
Other names | Nora lesion or Nora disease[1][2] |
Specialty | Orthopedics |
Symptoms | Painless lump in finger or toe[1] |
Risk factors | Possibly trauma in a minority[1] |
Diagnostic method | Medical imaging[1] |
Differential diagnosis | Mainly subungal exostosis[1] |
Treatment | Surgical excision.[1] |
Prognosis | Up to 50% recur after surgery[1] |
Frequency | Rare,[2] <5% of cartilage tumors,[3] M=F[1] |
Bizarre parosteal osteochondromatous proliferation (BPOP), also known as Nora's lesion,[4] is a type of non-cancerous bone tumor belonging to the group of cartilage tumors.[1][2][5] It is generally seen in the tubular bones of the hands and feet,[6] where it presents with a rapidly enlarging painless lump in a finger or toe.[1]
It is composed of bone, cartilage and spindle cells.[1] Some people report previous trauma.[1]
Diagnosis is by medical imaging.[1] Treatment is by surgical excision.[1] Up to 50% recur after surgery.[1]
It is rare,[2] and occurs more often in the 20s and 30s.[1] Combined with subungal exostosis, it accounts for less than 5% of cartilage tumors.[3] Males and females are affected equally.[1] The condition was first described by Frederick E. Nora in 1983.[6][7]
BPOP generally presents with a 1–3 cm painless lump in a finger or more frequently a toe.[1] Growth can be rapid.[2]
It is composed of bone, cartilage and spindle cells.[1] A small number of people have reported previous trauma.[1]
Medical imaging usually shows a well-defined wide-based bony growth on the surface of bone.[6]
BPOP is distinct from subungal exostosis.[1][6] Conditions that may appear similar to BPOP include: myositis ossficans, ostechondroma, surface osteosarcoma and granulomatous infection.[2]
Treatment is by surgical excision.[1]
BPOP is rare.[2] It is most often seen in people in their 20s and 30s.[1] Combined with subungal exostosis, it accounts for less than 5% of cartilage tumors.[3] Males and females are affected equally.[1][6]
Bizarre parosteal osteochondromatous proliferation was first described by Frederick E. Nora in 1983.[6][7] Generally in the US, it has been thought of as a mouthful and hence it is sometimes referred to as Nora's lesion.[4]
In 1998 a report of a similar lesion to BPOP was reported in a wallaby.[8]