Second toe swelling: Nora's lesion or glomus tumour, case report and literature review

We report a rare case of bizarre parosteal osteochondromatous proliferation (BPOP, Nora's lesion) of the right second toe in a 60-year-old man who presented with painful, bluish and bulbous swelling of the right second toe without any break in the skin.

Physical examination, plain radiography and magnetic resonance imaging (MRI) scan of the foot, histology of the excised tissue.

Bizarre parosteal osteochondromatous proliferation.

Radiographs showed a calcified/ossified lesion adjacent to the tuft of the terminal phalanx of the second toe. MRI showed a small low signal nodule on T1- and T2-weighted images in a subungual position adjacent to the terminal phalanx with sclerosis. The second toe was excised and the histology from excised tissue was consistent with "bizarre parosteal osteochondromatous proliferation". There was no malignant change on histology. Local excision of the entire lesion was done and there has been no recurrence to date.

BPOP, although a benign lesion, behaves aggressively with rapid growth and has a high risk of local recurrence after local resection (Nora et al. in Am J Surg Pathol 7(3):245-250, 1983; Meneses et al. in Am J Surg Pathol 17(7):691-697, 1993). Its clinical presentation can be confused with glomus tumour, subungual exostosis and enchondroma. The distinguishing features of BPOP and several relevant different differential diagnoses are discussed in this case report.