Free-ranging Eurasian otter (Lutra lutra) with rare osteoblastic osteosarcoma: a forensic and genetic investigation from central Italy

Background The Eurasian otter Lutra lutra experienced a dramatic decline in Europe during the 20th century. The urbanization of human population following the abandonment of countryside as well as reintroduction plans led to a recent recovery in many areas. Case presentation We investigated both cause of death and genetic origins of a recently discovered dead otter specimen in Tuscany, a region of central Italy where the species disappeared three decades ago. The necropsy was performed using a forensic approach. We also sequenced three gene fragments [cytochrome-oxidase subunit I (COXI), cytochrome-b (cytb), control region (D-loop)] of the mitochondrial DNA (mtDNA), to infer to which populations the rescued individual was genetically closest to. Then, we compared these sequences with those retrieved from fecal samples collected in north east Italy as well as with many others downloaded from the GenBank. Conclusion This is the first case of a neoplastic lesion in a bone tissue of wild Eurasian otter, with morphological features compatible with osteoblastic osteosarcoma. Molecular analyses revealed a high affinity of the i