Epithelioid Malignant Mesothelioma in Dogs: A Case Series
R. Jyothi Priya *
Department of Veterinary Pathology, Veterinary College and Research Institute, Orathanadu, Tamil Nadu Veterinary and Animal Sciences University, Orathanadu, Tamil Nadu, India.
E. Tamileniyan
Department of Veterinary Medicine, Veterinary College and Research Institute, Orathanadu, Tamil Nadu Veterinary and Animal Sciences University, Orathanadu, Tamil Nadu, India.
K. Kannan
Veterinary Clinical Complex, Veterinary College and Research Institute, Orathanadu, Tamil Nadu Veterinary and Animal Sciences University, Orathanadu, Tamil Nadu, India.
K. Thilagavathi
Department of Veterinary Pathology, Veterinary College and Research Institute, Orathanadu, Tamil Nadu Veterinary and Animal Sciences University, Orathanadu, Tamil Nadu, India.
M. Veeraselvam
Department of Veterinary Medicine, Veterinary College and Research Institute, Orathanadu, Tamil Nadu Veterinary and Animal Sciences University, Orathanadu, Tamil Nadu, India.
K. Jayakumar
Department of Veterinary Surgery and Radiology, Veterinary College and Research Institute, Orathanadu, Tamil Nadu Veterinary and Animal Sciences University, Orathanadu, Tamil Nadu, India.
*Author to whom correspondence should be addressed.
Abstract
Cytological evaluation of serosal fluids, advanced imaging techniques and histopathological examination are essential diagnostic tools for confirmation of the disease. Cytologically, malignant epithelioid mesothelioma is characterized by clusters of polygonal cells with abundant eosinophilic cytoplasm, increased nuclear to cytoplasmic ratio, multinucleation, prominent nucleoli and characteristic knobby cell borders. Two Dalmatian dogs aged 9 and 12 years and one 12-year-old non-descript male dog were presented to the Veterinary Clinical Complex, VC & RI, Orathanadu with dyspnoea, vomiting and rapid weight loss. Clinical examination revealed severe respiratory distress due to pleural effusion and ventral abdominal oedema. Haematological findings included severe anaemia, hemoconcentration and neutrophilic leucocytosis, while serum biochemical analysis showed hypoproteinemia, hypoalbuminemia, hypoglycemia and elevated hepatic enzyme levels. Thoracic and abdominal radiography revealed pleural and peritoneal effusions with diffuse nodular serosal thickening. Cytological examination of pleural and peritoneal effusions demonstrated pleomorphic epithelioid mesothelial cells with knobby borders, pseudo-acinar arrangements, multinucleation and numerous mitotic figures suggestive of malignant epithelioid mesothelioma. Histopathology of ultrasound guided pleural biopsy sample confirmed papillary and pseudo-acinar malignant mesothelial proliferation with marked cytologic atypia and abundant eosinophilic cytoplasm. The study highlights the occurrence of malignant epithelioid mesothelioma in older male dogs with associated paraneoplastic syndromes including anaemia, hypoglycemia, paraneoplastic hepatopathy and wasting syndrome.
Keywords: Cytology, dog, histopathology, malignant epithelioid mesothelioma, paraneoplastic syndrome, pleural effusion