Nora’s lesion of the distal ulna: a case report

Nora’s lesion, also known as bizarre parosteal osteochondromatous proliferation (BPOP), is a very rare benign lesion with few published cases. BPOP is more common in adults during the second to third decades of life, and usually occurs on the hands and feet. Radiologically, it appears as a calcified mass attached to the bone cortex that grows rapidly and that recurs easily following resection. Aggressive features on imaging and confusing histopathological findings usually result in misdiagnosis or mistreatment. Herein, we present a case of a rare bony tumour involving the distal ulna presenting as a painless growing mass. An excisional biopsy with clear margins was performed without disturbing the ulnar nerve and arteries. There was no recurrent mass or calcified lesion 1 year after surgery. Based on its rarity and difficult diagnosis, BPOP should be considered in the differential diagnosis of a painless mass in the distal ulnar region. Careful follow-up after surgery is essential, even without lesion recurrence.

Nora’s lesion: bizarre parosteal osteochondromatous proliferation in right foot: a case report

<p class="abstract"><span lang="EN-US">Nora’s lesion is a benign lesion involving mainly the proximal phalanges, metatarsals or metacarpals in the hands and feet. It may be easily confused with a malignant entity and was first identified and reported by Nora et al. in 1983. We present a case of a 12 years old female with complains of a swelling over the right foot noticed 4 months ago. Plain radiograph revealed heterotrophic calcification over the dorso-lateral aspect of the head of the first metatarsal. MRI scan of the foot was suggestive of a benign pathology with a differential of bizarre parosteal osteochondromatous proliferation (BPOP) or an osteochondroma. The patient was managed with excision biopsy and lesion was excised along with the pseudo-capsule and adjoining periosteum. Cortex appeared normal and wound was washed with hydrogen peroxide and incision closed. Histopathology report was suggestive of Nora’s lesion. One year follow up of the patient showed no recurrence. BPOP proliferation is a benign lesion however differentials need to be kept in mind and treatment with excision of the lesion along with the pseudo-capsule and periosteal tissue beneath the lesion has low rates of recurrence. </span></p>

Bizarre Parosteal Osteochondromatous Proliferation (Nora's Lesion) in the Medial Sesamoid of the First Toe

Bizarre parosteal osteochondromatous proliferation, or Nora's lesion, is a unique bony lesion that generally originates from the small bones of the hands and feet in young adults. We report a case of a bizarre parosteal osteochondromatous proliferation originating from the medial sesamoid of the first toe that was managed surgically by en bloc excision. At 5-year follow-up, there was no evidence of recurrence.

Nora's Lesion: Bizarre Parosteal Osteochondromatous Proliferation Causing Splay Foot Deformity: A Case Report

Nora's lesion, or bizarre parosteal osteochondromatous proliferation (BPOP), is a rare benign lesion that is made up of varying degrees of cartilage, bone, and spindle cells. Most notably, calcification of the cartilage or “blue bone,” is a feature of the disorder. The condition principally affects long tubular bones of the hands and feet, and is generally seen in patients in their second and third decades of life. We present a case of BPOP occurring in the second interspace with symptoms that would be consistent with a more common diagnosis of predislocation syndrome, or a second interspace neuroma. This case study may help the clinician in considering a more subtle cause of a splay deformity in the second interspace, and walk through the diagnostic and treatment course for BPOP.