Canine malignant lymphomas: comparison of morphologic and immunologic parameters
Holmberg, C.A.; Manning, J.S.; Osburn, B.I.
Journal of the National Cancer Institute 56(1): 125-135
1976
ISSN/ISBN: 0027-8874 PMID: 768497 Document Number: 97194
Twenty-three canine malignant lymphomas were studied to correlate morphological and immunologic properties of the neoplastic cells. Morphological characterization included histological classification of cell type and growth pattern, anatomical distribution of lesions, and transmission electron microscopical examination. Parameters examined to indicate B- or T-cell nature of lymphoma cells included demonstration of mitogen responsiveness, cell-surface Ig, spontaneous rosette formation with human RBc, and scanning electron microscope (SEM) examination of cell-surface features. Results indicated that the cells from histiocytic lymphomas were lymphocytes rather than histiocytes or macrophages. Most cells from lymphomas examined possessed cell-surface Ig, indicating B-cell nature. The cell types represented by the different Ig-positive lymphomas were compatible with maturation arrest at different stages in normal lymphocyte differentiation. For the two most common histological cell types, mitogen responsiveness and the presence of cell-surface Ig indicated that diffuse, poorly differentiated lymphocytic cases were biologically heterogeneous, whereas nodular histiocytic lymphomas were biologically homogeneous. Most canine lymphomas had a multicentric anatomical distribution; however, one thymic and two alimentary forms were observed. Lymphomas with a nodular pattern in lymph nodes had multifocal splenic involvement centered on small arteries, whereas lymphomas with a diffuse pattern in lymph nodes had diffuse involvement of splenic white pulp. The cells of Ig-positive and Ig-negative neoplasms examined by SEM were predominantly of the smooth-cell type.