Citomorphological diagnostic of malignant histiocytic neoplasm in dogs

Abstract

From the literature results that it can’t be found information, for the canine species, about the cytomorfological differential diagnosis in the malignant histio-dendritical proliferations. In this paper the authors want to bring a series of exclusive cytomorphologic arguments for the positive diagnosis and differential diagnosis of canine malignat proliferations, which have as a proliferative cellular base, the histiocytic cell and the dendritic cell. In this study we discuss three cytomorphologic forms of malignant proliferations of the histiocytic and dendritic cell. Two of these forms, the dendritic sarcoma and the histiocytic sarcoma, belong to the malignant lymphoma category; these are solid tumors localized in the tegument, lymph nodes and spleen. The third histiocytic proliferation forms is the histiomonocytic leukemia, which belongs to the liquid forms, localized in the hematopoietic marrow, with permanent cytemic discharge in the peripheral blood. Between the dendritic sarcoma and the histiocytic sarcoma diagnosis confusions can be created. The differential diagnosis can be made with difficulty on the histopathological sample, but very easily on the cytomorphological ones. The differences obtained by the cytomorphological technique, which ensures at the end the differential diagnosis, are generated by two easily identifiable aspects: the first one consist in the presence of a large cytoplasm with multiple prolongations in dendritic sarcoma and total absence of this aspect in the histiocytic malignant cellular forms; the second aspect consists in the presence of a true syncytial cellular pointing out a veritable cytoplasmic mega-anastomosis in the dendritic sarcoma, and the lack of this aspect in the histiocytic proliferations. Histiomonocytic leukemia differs fundamentally from any other leukemia cell form by the the existence of a very high cellular polymorphism with cell gigantism and monstrosities. Finally, we make the assessment that besides the cytomorphological exam, there is no other methodology of these histiocytic proliferative variants except immunohistochemistry, which is an expensive and time consuming method. Histopathology can only provide the information that the malignant proliferation have as a cellular base, the histiocytic cell.