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Rosciani A.S.,Servicio de Diagnostico Histopatologico y Citologico | Merlo W.A.,Servicio de Diagnostico Histopatologico y Citologico | Insfran R.M.,Servicio de Diagnostico Histopatologico y Citologico | Benitez J.S.,Servicio de Diagnostico Histopatologico y Citologico | Ortega H.H.,Cat. Biologia Celular
Revista Veterinaria | Year: 2010

Myoepithelial cells (MEC) proliferate in complex and mixed canine mammary gland tumors. They usually transform into cells from myxoid, chondroid and bone tissues. Different attempts to characterize and make them evident have been made, by using specific markers. Myoepithelial cells suffer phenotypic transformations during proliferation, and different types of such transformations have been described: fusiform, hypertrophic, stellate and rounded myoepithelial cells and chondroblasts. The purpose of this assay is to present the results from the proliferation cells' nuclear antigen (PCNA) and alpha smooth muscle actin (AA) double immunohistochemical technique, which revealed CME proliferation. In addition, to report the description of morphologically identified MEC's varieties on hematoxilin and eosine slides. Fifty four canine mammary tumours diagnosed as simple (SC) and complex carcinomas (CC), and carcinomas in mixed benign tumours (CMT), were studied. The five MEC's varieties (previously described by other authors, were recognized. All types, except for chondroblasts and or osteocytes, were observed in CC, whereas all of them were seen in CTM. SC showed the presence of fusiform and hypertrophic MEC. Positive AA cytoplasmic staining pattern was seen in the all of fusiform and hypertrophic MEC. Less than 50% of stellate MEC was weakly reactive. No positive rounded MEC were observed. Chondroblasts and osteocytes were observed with a weak stain only in two occasions. CC (17,33) and CTM (15,67) showed the highest PCNA reactive MEC's nucleus counts over SC (12,56), although no significant statistics differences were found. These findings are in agreement with the current presumption that MEC proliferate, transform and give rise to different tissues such as fibrous, myxoid and chondroid. Source


Merlo W.A.,Servicio de Diagnostico Histopatologico y Citologico | Rosciani A.S.,Servicio de Diagnostico Histopatologico y Citologico | Insfran R.M.,Servicio de Diagnostico Histopatologico y Citologico | Lopez J.E.,Servicio de Diagnostico Histopatologico y Citologico | Maccio O.A.,Servicio de Diagnostico Histopatologico y Citologico
Revista Veterinaria | Year: 2010

The purpose of this work is to present the results from the evaluation of different parameters in twelve female dogs with mammary tumors before and after treatment with tamoxifen. Animals were in clinical stages III and IV according to the World Health Organization TNM system (tumor, node, metastasis). Samples obtained using fine needle aspiration cytodiagnosis and pre-treatment tumor biopsies were analyzed. Mammary gland extirpations were performed after tamoxifen treatment. Histopathology was performed to classify the neoplasms, as well as to determine histological malignancy grade and to evaluate other parameters such as presence of necrosis, vascular invasion, and lymphoplasmacytic infiltration. The cytodiagnosis was in concordance with the histological classification of surgical specimens in 50% of the cases. The histological classification, the histological grade of malignancy determination, and the assessment of vascular invasion, lymphoplasmacytic infiltration, and necrosis showed many differences between pre-treatment biopsies and post-treatment surgical samples. These differences are considered as a consequence of the small size of the biopsies that would not reflect the particular heterogeneity of the tumors. Furthermore, these differences do not allow to confirm neither reject tamoxifen pharmacological effectiveness, which period of administration was short and implemented in patients in advanced clinical stages. Source

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