animals Article Four Unusual Cases of Congenital Forelimb Malformations in Dogs Simona Di Pietro 1 , Giuseppe Santi Rapisarda 2 , Luca Cicero 3, * , Vito Angileri 4 , Simona Morabito 5 , Giovanni Cassata 3 and Francesco Macrì 1   Citation: Di Pietro, S.; Rapisarda, G.S.; Cicero, L.; Angileri, V.; Morabito, S.; Cassata, G.; Macrì, F. Four Unusual Cases of Congenital Forelimb Malformations in Dogs. Animals 2021, 11, 813. https://doi.org/10.3390/ ani11030813 Academic Editor: Francesca Ciotola Received: 1 February 2021 Accepted: 11 March 2021 Published: 14 March 2021 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). 1 Department of Veterinary Sciences, University of Messina, Viale Palatucci, 98168 Messina, Italy; dipietros@unime.it (S.D.P.); francesco.macri@unime.it (F.M.) 2 Department of Veterinary Prevention, Provincial Health Authority of Catania, 95030 Gravina di Catania, Italy; grapisarda1975@gmail.com 3 Institute Zooprofilattico Sperimentale of Sicily, Via G. Marinuzzi, 3, 90129 Palermo, Italy; giovanni.cassata@izssicilia.it 4 Veterinary Practitioner, 91025 Marsala, Italy; vitoang@gmail.com 5 Ospedale Veterinario I Portoni Rossi, Via Roma, 57/a, 40069 Zola Predosa (BO), Italy; morabitosimona759@gmail.com * Correspondence: lucacicero031182@gmail.com Simple Summary: Congenital limb defects are sporadically encountered in dogs during normal clinical practice. Literature concerning their diagnosis and management in canine species is poor. Sometimes, the diagnosis and description of congenital limb abnormalities are complicated by the concurrent presence of different malformations in the same limb and the lack of widely accepted classification schemes. In order to improve the knowledge about congenital limb anomalies in dogs, this report describes the clinical and radiographic findings in four dogs affected by unusual congenital forelimb defects, underlying also the importance of reviewing current terminology. Abstract: Four dogs were presented with thoracic limb deformity. After clinical and radiographic examinations, a diagnosis of congenital malformations was performed for each of them. In one case, a deformity involving both the radial and ulnar side of the distal limb was observed. Based on clinical and radiological evaluations, a diagnosis of postaxial terminal longitudinal ulnar hemimelia was performed. The term ectrodactyly was used to refer different malformations characterized by skin and soft tissue separation of the distal forelimb observed in two dogs. Simple complete uncomplicated syndactyly of the right forelimb, and complex incomplete uncomplicated syndactyly of the left forelimb were diagnosed in the fourth case. To the authors’ knowledge, ectrodactyly and simple complete uncomplicated syndactyly are very uncommon anomalies in companion animals and have been rarely documented. Moreover, postaxial terminal longitudinal ulnar hemimelia has still not been reported in dogs. Keywords: congenital limb deformity; dog; ectrodactily; syndactyly; ulnar hemimelia 1. Introduction Appendicular skeletal dysostoses are a group of dysmorphologies arising from al- terations of the limb’s developmental process, resulting in a wide range of abnormalities involving individual bones or portions of bones of the growing embryo body extremi- ties [1]. Hereditary (genetic aberrations) and environmental factors (drugs, maternal diseases, radiations and trauma) can cause an abnormal developmental process or an interference with a normal developmental process, respectively [2,3]. Limb formation is an intricate process, which takes place during the first weeks (from D23 to D35) of gestation in dogs [3–5] Presumptive limb-forming fields are early established Animals 2021, 11, 813. https://doi.org/10.3390/ani11030813 https://www.mdpi.com/journal/animals