Lamb congenital lymphatic malformation - a case report

Lymphatic malformations have been rarely reported in literature either in humans or in animals. However, in recent years, concern about these malformations in humans has increased. A five-month-old Rasa Aragonesa male lamb was received at the Ovine Clinical Service of the Veterinary Faculty of Zaragoza, Spain, with a history of cervical protuberances coming from birth. The lamb showed three round swollen lumps (5–12 cm in diameter) parallel to the trachea on the left side of the neck. Clinical examination, haematology, ultrasonography, fluid examination and histopathology were performed. No abnormalities were found in blood samples and ultrasound confirmed a multicystic lesion with internal separations. Histological evaluation of the tissue revealed dilated lymphatic vessels and channels in the dermis and hypodermis; some lymphatic vessels were filled with amorphous proteinaceous material and occasional lymphocytes and macrophages. These protuberances were diagnosed as congenital lymphatic malformations. Most of the gross and microscopical lesions were very similar to those described in humans. To the authors’ knowledge, this is the first time that a congenital lymphatic malformation is described in sheep. Sheep, cervical protuberances, congenital disorders, lymphangioma Lymphatic malformations (LMs) are rare vascular malformations both in humans and animals. However, in recent years, concern about these malformations in humans has increased. When describing vascular anomalies the nomenclature is confusing. Some authors classified lymphangiomas as being: capillary (or simplex), cavernous, and cystic lymphangiomas (Yildirim et al. 2004; Wiegand et al. 2008). There are other classifications based on morphological aspects and they are divided into: macrocystic, microcystic and combined lymphagiomas (Wiegand et al. 2008). Currently, LMs are classified into two categories: “vascular tumours” and “vascular malformations” based upon clinical, histological and biochemical differences (Wiegand et al. 2008; Perkins et al. 2010). It has not been formally demonstrated that LMs are malignant disorders, and despite their unclear aetiology, some observations suggest a genetic aetiology because up to 40% of LMs detected during foetal development occur in children who present chromosomal anomalies (Perkins et al. 2010). In cattle, LMs have been described and a hypothesis of a genetic disorder transmissible through an autossomal recessive gene was also established (Wanke et al. 1990). These authors described the clinical case of two calves showing cervical hygroma (macrocystic LMs) at birth and they concluded that analysis of the pedigrees indicates that the lymphocysts may represent a hereditary malformation. As this is an unknown and rare case in ruminants, the aim of this work was to provide veterinary practitioners and researchers with some knowledge achieved throughout the study of this clinical case. ACTA VET. BRNO 2014, 83: 239–241; doi:10.2754/avb201483030239 Address for correspondence: Dr. Delia Lacasta Animal Pathology Department Veterinary Faculty, University of Zaragoza Miguel Servet 177, 50013 Zaragoza, Spain Phone: +34 976 761 578 E-mail: [email protected] http://actavet.vfu.cz/