Elsevier

The Journal of Hand Surgery

Volume 46, Issue 4, April 2021, Pages 344.e1-344.e9
The Journal of Hand Surgery

Case Repository
Bizarre Parosteal Osteochondromatous Proliferation (Nora Lesion) in Pediatric Phalanges

https://doi.org/10.1016/j.jhsa.2020.05.002Get rights and content

Bizarre parosteal osteochondromatous proliferation, or Nora tumor, is an uncommon lesion affecting the tubular bones of the hands and feet. Normally arising from the cortical surface and periosteum of these bones, these lesions histologically consist of a hypercellular cartilaginous cap covering a bony stalk that is surrounded by ossified areas and spindle cell stroma. The differential diagnosis includes conditions involving the periosteum such as chondrosarcoma, parosteal osteosarcoma, osteochondroma, turret exostosis, and florid reactive periostitis. The only effective treatment is wide surgical excision; nevertheless, local recurrence rates are extremely high and may necessitate revision surgery. In the present study, we report 3 cases of Nora lesion located in the hand in pediatric patients. The diagnosis in these cases was challenging owing to their presenting symptoms and radiographic findings. The diagnosis was made based on characteristic findings noted on the radiographic images and was confirmed by histological examination following excision.

Section snippets

Case 1

A 12-year-old boy presented with a painless mass on the middle phalanx of his right middle finger (Fig. 1). The patient was otherwise in good health, was on no medications, and had no significant past medical history. There was a history of trauma 6 months previously while playing at school. On physical examination, he had a lobulated lesion along the middle phalanx of the right middle finger. It was 3 cm in diameter and extended from the radial to the volar aspect of the finger. Radiographs

Discussion

Bizarre parosteal osteochondromatous proliferation is an uncommon benign reactive lesion that arises from the periosteum through a process of cartilaginous metaplasia. The age distribution of cases reported in the literature ranges from 8 to 74 years with most cases occurring in the 20s and 30s1, 2, 3 without sex predilection. We report 3 cases between the ages of 2 and 12 in this series, all arising in the middle or proximal phalanx. In approximately three-quarters of all cases of BPOP, the

Acknowledgements

The authors of this study wish to thank Marybeth Ezaki, MD, for her invaluable assistance with the manuscript preparation and submission.

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