Acral congenital superficial dermal lymphatic malformations in two unrelated cats: clinicopathological, dermoscopic and ultrastructural findings

Background: Cutaneous vascular malformations (CVM) represent a spectrum of human diseases identified at birth or in paediatric patients and classified according to the type of vessel affected. Confusing classification in human medicine has led to misdiagnoses and frequent nomenclature revision. Cutaneous lymphatic malformations (CLM) are reported sporadically in humans. Objective: To describe the clinicopathological findings of superficial dermal cutaneous lymphatic malformations (SDCLM) in two cats. Animals: Two unrelated adult domestic short hair cats. Methods: The two cats were evaluated clinically and with a dermoscope for recurrent swelling and presence of vesicles oozing serosanguineous fluid affecting the right and left hind foot, respectively, since birth. Skin biopsy specimens were collected for histopathological and immunohistochemical evaluation and electron microscopy. Results: A CVM was suspected based on the age of onset, clinical signs, results of diagnostic imaging and histopathological findings. Dermoscopy was used to describe the alterations of the skin surface. The involvement of the lymphatic vessels was confirmed using immunohistochemical findings and electron microscopy. Conclusion and clinical importance: To the best of the authors’ knowledge, this is the first description of the clinical, dermoscopic, histopathological and ultrastructural characteristics of SDCLM in cats resembling the human counterpart. SDCLMs are rare conditions and appropriate histopathological and immunohistochemical confirmation is required to avoid misdiagnosis and mistreatment.