Methods for the differentiation of giant cells in canine and feline neoplasias in paraffin sections.

Abstract

In the following study cells with at least two cell nuclei are addressed as giant cells. In 47 biopsies of feline neoplasias (fibrosarcoma, haemangioendothelsarcoma, mammary adenocarcinoma, osteoidsarcoma, complex sarcoma), and 25 biopsies of canine neoplasias (malignant seminoma, mammary adenocarcinoma, haemangioendothelsarcoma, fibrosarcoma, osteoblastic sarcoma, complex sarcoma) giant cells are distinguished either as neoplastic giant cells or as reactive (non-neoplastic) giant cells. Cell nuclei of neoplastic giant cells which are labelled with the monoclonal antibody MIB 1 are mitotic active; cell nuclei are polymorph and can show atypical mitosis; the cytoplasmic reaction with tartrate resistant acid phosphatase (TRAP) is negative. Negative reactions with MIB 1, positive TRAP staining and homogeneous cell nuclei are distinctive for osteoclast-like glant cells. Other non-neoplastic giant cells (e.g. foreign body cells, Langhans-giant cells) are negative with both MIB 1 and TRAP. Double staining of paraffin sections is possible. Routine formalin-fixation, embedding in paraffin and decalcifying tissue samples do not interfere with MIB 1 immunoreactions or TRAP reactions. Methodological modifications that were necessary for the preparation of paraffin sections from canine and feline tissue samples are discussed. As the presence of neoplastic giant tumour cells is an index for a poor prognosis in human medicine, not only the entity of the tumour must be named, but also the exact significance of the giant cell type:, e.g. fibrosarcoma with osteoclast-like giant cells, hepatic carcinoma with reactive giant cells, malignant seminoma with neoplastic giant cells, angiosarcoma with both neoplastic giant cells and osteoclast-like giant cells. This would enable the classification of further neoplasias dealing with clinical courses of the diseases. Over the past years our stains have remained stable. It is possible to carry out retrospective investigations with archived tissue samples and make permanent preparations. A reclassification and a refined form of diagnosis (tumour and giant cell type) would be recommended.