Histological and immunohistochemical evaluation of stroma variations and their correlation with the Ki-67 index and expressions of glucose transporter 1 and monocarboxylate transporter 1 in canine thyroid C-cell carcinomas.

Canine thyroid C-cell carcinomas (CTCCs) are malignant tumors derived from calcitonin-producing C-cells of the thyroid gland. This study aimed to investigate the histological diversity of CTCCs from the viewpoint of stroma variations and to investigate their components by histological and immunohistochemical analyses including semiquantitative analysis of the density of microvessels (MVs) and α-SMA-positive cell count. Moreover, we examined whether the variations correlated with the Ki-67 index and expressions of glucose transporter 1 (GLUT-1) and monocarboxylate transporter 1 (MCT-1). Three stroma types (reticular, R, nest, N, and trabecular, T) were observed in CTCCs, and 21 cases were divided into 3 variations based on their combinations: mixed R and N (R/N) (n=7), simple N (n=7) and mixed T and N (T/N) (n=7). Immunohistochemically, stroma types depended on morphological features of α-SMA/fibronectin/laminin/collagen type IV-positive stroma cells. The density of MVs in R/N tended to be highest, and the density of those in N was significantly higher than the density of those in T/N (P=0.028). The α-SMA-positive cell count for N tended to be the lowest among the 3 variations. The Ki-67 index for R/N was significantly higher than those of the other variations (vs. N, P=0.007; vs. T/N, P=0.03), and that for T/N tended to be higher than that for N. Although there were no significant differences, GLUT-1 and MCT-1 expressions tended to be low in N. We concluded that stroma variations reflect tumor cell proliferation and expressions of GLUT-1 and MCT-1 in CTCCs.

Histological and immunohistochemical evaluations of lobular dissecting hepatitis in American cocker spaniel dogs.

Histological and immunohistochemical evaluations of lobular dissecting hepatitis (LDH) were performed in nine American cocker spaniel dogs. Histological examination showed diffuse fibrosis with weak inflammatory reaction of extensive neutrophils, macrophages, lymphocytes and plasma cells. Immunohistochemical examination revealed that the myofibroblastic cells positive for anti-α-smooth muscle actin and anti-vimentin antibodies produced reticular and collagen fibers and brought about the dissection of hepatic cords and diffuse disappearance of hepatocytes. Reticular fibers invading between hepatocytes and the surrounding small group of hepatocytes were strongly positive for anti-collagen type III and anti-collagen type IV antibodies. The positivity to anti-fibronectin and anti-laminin antibodies was frequently continuous on the basement membrane of the sinusoids of the remaining hepatic cords and between the hepatocytes. Positive findings for anti-E-cadherin antibody were not observed between the hepatocytes showing positive findings for anti-collagen type III and anti-collagen type IV antibodies. These results may explain the expression of fibronectin and laminin that occurs prior to the invasion of reticular fibers between hepatocytes. The present study further suggests that expression of an extracellular matrix mainly containing fibronectin and laminin between the hepatocytes and proliferation of collagen fibers and reticular fibers have a major role in the rupture of the hepatic cords and disappearance of hepatocytes.