Soft tissue chondroma of the index finger: clinical, histological and radiological findings in a unique case.

A chondroma is a benign, slow-growing cartilaginous tumor. When arising in the medullary cavity of a bone it is referred to as an enchondroma-a very common bone tumor. When occurring in soft tissue without any connection to bone, which is extremely rare, it is known as a soft-tissue chondroma (STC). A 38-year-old female presented with a 2- year history of right index finger pulp swelling in the absence of trauma. On physical examination a firm, immobile nodule, approximately 1 cm in diameter, was observed on the palmar side of the right index finger. The overlying skin was normal. Plain X-ray showed a dense, soft tissue shadow without calcification in the right index finger pulp, but the adjacent bones were intact. MRI showed a 1-cm diameter, well-demarcated lesion with intermediate signal intensity on T1-weighted images and high signal intensity on T2-weighted images. MRI also showed that the tumor had no bony involvement and that the adjacent bones were normal. Histopathological examination of the biopsy specimen showed lobules of mature hyaline cartilage with chondrocytes in the lacunae in the dermal and subdermal layers. Mitotic figures and an increase in cellular atypism were not observed. Based on the histopathological and radiological findings, the mass was thought to be an STC and total excision was performed. Examination of the excised mass confirmed the diagnosis of STC. STC should be considered in patients with a slowly growing, mildly painful cutaneous mass.