Nora's lesion of the thumb and a differential diagnosis

In this paper, we report a rare case of a solitary osteochondromatous tumour on the volar tip of the thumb of a 47-year-old woman. An X-ray examination showed a heavily calcific mass close to the bone and an alteration of the bone, next to the lesion. A wide-margin biopsy was performed on this tumour and a histological examination was conducted, which showed the characteristics of a bizarre parosteal osteochondromatous proliferation of the bone (Nora's lesion). The lesion was 0.8×0.9 cm. This neoplasm has a high tendency for local recurrence, although metastatic behaviour has not yet been reported. Due to its possible recurrence, this lesion requires radical surgery and, at times, amputation is necessary. In this case, wound healing was uncomplicated and there was no deficit after surgery. No recurrences were observed after 2 years from the surgery. At the end, we describe six differential diagnoses for the Nora's lesion. We explain some important characteristics of every one of the six lesions. © 2010 Springer-Verlag.