Immunohistochemistry of nodular dermatofibrosis in a German Shepherd – a case report

This case report describes nodular dermatofibrosis in an 11-year-old female dog of the German Shepherd breed. Previously, at the age of 6 years (initial stage), a sample from a tumorous nodule on her back was removed. Histological examination of the sample from this period showed hyperplasia of cells with a lobular structure. Immunohistochemistry staining demonstrated focal positivity to pancytokeratin. In the terminal stage (at 11 years of age), clinical examination revealed apathy, uncoordinated movement of the hind limbs, obstipation, anorexia and occasional vomiting with progressive weight loss. Skin inspection found multiple skin ulcerating tumorous lesions localized in the sacral region of the back and intercostally, partly fluctuating around the size 4 cm in diameter. Necropsy revealed an intraabdominal tumour localized among intestinal loops. Nodular lesions were found also in the lung parenchyma, on the dorsal surface of the epiglottis, in the myocardium, the cortex and the medulla of the kidneys, the adrenal gland, and in the intestinal wall. Histological analysis showed systemic production of fibrous nodules and formation of fibrous tissue with atrophy of parenchyma tissue. However, no connection between dermatofibrosis and adenocarcinoma of the kidney was found in this case, which was supplemented with pancytokeratin antibody. CD3 + lymphocytes were observed mainly in the zone of cell proliferation and in the interface towards the fibrous layer. Macrophages were seen mainly in the transitional zone between cellular and fibrous part. This indicated participation of monitored immunocompetent cells in fibroblast degradation.