Ulnar dimelia and a rare variant ulnar trimelia: Case reports

Ulnar dimelia is an infrequent congenital anomaly of the upper limb characterized by the duplication of the ulna, absence of the radial ray, and polydactyly. We report on 2 cases of young girls with upper limb abnormalities who were brought to our Advanced Imaging Department for specialized imaging evaluation. The first case is a 15-month-old girl with a typical manifestation of ulnar dimelia. X-ray images of her right forearm and hand showed 2 ulnar-like bones, absence of the radial ray, and post-axial polydactyly. Our second case is a 7-year-old girl with evident limited pronosupination and shortening of the left forearm. Findings from computed tomography evaluation included ulnar duplication, one of which had a bifid aspect, with characteristics that are similar to ulnar proximal and distal epiphysis. The latter case which, to the best of our knowledge, has not been reported in the literature, is a rare variant of ulnar dimelia, that we have called ulnar trimelia. In this contribution, we emphasize the importance of an adequate diagnostic imaging approach for accurate recognition of upper limb anomalies, so that the treatment selection is appropriate to achieve better health outcomes and improve patients’ quality of life. Our descriptions and images presented in this contribution form the basis for further research.