Indagini morfologiche ed immunoistochimiche sulle neoplasie testicolari del cane

A retrospective survey on a color of 232 dogs submitted to the Department of Veterinary Anatomic Pathology for necropsy revealed that testicular tumors in dogs are frequent and the seminoma is one of the most represented tumor in this species. In addition this finding suggested that, as reported in men, testicular tumor in dogs have increased during the last years. Since Seminoma is one of the most common tumor in man, it was hypothesized that the dog might represent a good animal model for the study of human seminoma. In human, two type of seminoma are described: the spermatocytic seminoma, that derives from mature spermatocytes and demonstrates benign behaviour, and the classical seminoma, that arises from undifferentiated seminal germ cells (i.d. gonocytes), is more malignant and frequently metastasized. In order to study the frequency of these two type of seminoma in the dogs, 43 testicular tumor with a previous diagnosis of seminoma were evaluated histologically with haematoxylin and eosin and periodic-acid Schiff (PAS) stains and immunohistochemically with an antibody directed against Placental Alkaline Phosphatase (PLAP) antigen, a marker of gonocytes. This study demonstrated the presence of two type of seminoma, classical and spermatocytic, in canine species and demonstrated that canine seminomas share morphological, histochemical and immunohistochemical features with the human counterpart. In addition, the occurrence of Carcinoma in situ (CIS, Seminoma precursors lesions) was demonstrated also in the dog. Carcinoma in situ (CIS ) has been considered as a part of a human male reproductive disorder defined Testicular dysgenesis syndrome (TDS). TDS comprehend a wide spectrum of clinical and histopathological disorders. In addition, it has been suspected that environmental pollutants oestrogen-like or anti-androgenic activity may play a role in the pathogenesis of TDS. In order to evaluate the occurrence of TDS in dogs, all the testes submitted to the histopathology service from 2006 have been examined morphologically for the presence of histological features of TDS and immunohistochemically with anti-PLAP antibody for the presence of CIS. Finally, stated the important role of oestrogen and its receptors in prostatic growth and differentiation and progression of prostatic carcinoma in human being, the expression of oestrogen receptors in normal, hyperplastic and neoplastic canine prostates has been evaluated. A progressive loss of oestrogen receptors expression in hyperplastic and neoplastic canine prostate and may account for the high degree of de-differentiation of canine prostatic carcinoma.