Lymphatic vessel density and VEGF-C expression are significantly different among benign and malignant thyroid lesions.

Thyroid cancer is the most frequent endocrine neoplasia worldwide. The route for metastasis and loco-regional invasion preferentially occurs by lymphatic vessels. For this reason, the assessment of lymphatic vessel density (LVD) is supposed to represent both a prognostic parameter and also a potential therapeutic target. In order to evaluate the value of LVD in benign and malignant thyroid lesions, we analyzed 110 thyroidectomy specimens using D2-40, a specific marker for lymphatic vessels and vascular endothelial growth factor C (VEGF-C), the most potent molecule of lymphatic proliferation. LVD was significantly different between papillary and follicular carcinomas in total (p = 0.045) and peritumoral area (p = 0.042). Follicular adenoma and follicular carcinoma showed an important difference of intra- (p = 0.019) and peritumoral (p = 0.033) LVD. VEGF-C was more markedly expressed in malignancies than in benign lesions (p = 0.0001). Almost all cancers with high positive VEGF-C expression also exhibited increased peritumoral LVD (p = 0.049) when compared with the benign lesions. Indeed, the high peritumoral LVD of malignant thyroid lesions is an important finding for surgery planning and supports the practice of total thyroidectomy in malignant thyroid neoplasm's since the lymphatic peritumoral vessels definitely are an escape path for tumor cells.

Avaliação da expressão dos membros da família de fatores de crescimento endotelial vascular e seus receptores e da densidade vascular sanguínea e linfática, em lesões malignas e benignas da tireóide / Evaluation of the family members of vascular endothelial growth factors and their receptors and blood and lymphatic vascular density in malignant and benign thyroid lesions

As neoplasias tireoidianas são importante causa de morbi-mortalidade. A patogênese da disseminação neoplásica pelo organismo é um complexo e intrigante processo pelo qual grande parte das neoplasias malignas se dissemina, a partir de um sítio de origem, para diferentes partes do organismo, utilizando como vias preferenciais os sistemas vasculares venoso e linfático. A expressão dos fatores de crescimento endotelial vascular e de seus receptores (VEGFs e VEGFRs) estão relacionados à angiogênese e linfangiogênese tumoral participando do diagnóstico, avaliação prognostica e tratamento de neoplasias malignas. O papel da angiogênese e da linfangiogênese na patogênese dos cânceres de tireóide ainda não foi completamente desvendado. Os diferentes padrões de comportamento dos tumores tireoidianos e de suas metástases variam de acordo com o tipo de tumor e ainda não foi completamente explorado se diferenças na expressão dos VEGFs e VEGFRs influenciam a metástase tumoral ou determinam um comportamento mais agressivo. Na presente tese, avaliamos a expressão imuno-histoquímica dos VEGFs e VEGFRs e a densidade vascular sanguínea e linfática nos bócios adenomatosos, tireoidites linfocitárias e adenomas foliculares, bem como nos carcinomas papilíferos e foliculares e suas regiões adjacentes. Posteriormente, correlacionamos nossos achados com os dados clínico-patológicos. Observamos que há um crescimento gradual na intensidade da expressão dos VEGFs e VEGFRs a partir do tecido tireoidiano com fenótipo normal, lesões proliferativas benignas e neoplasias malignas. Nos carcinomas, apesar da profusa expressão dos VEGFs e VEGFRs detectamos correlação estatisticamente significativa apenas do VEGF-D e VEGF-R3 com um pior estadiamento tumoral nos carcinomas papilíferos. A densidade vascular sanguínea foi superior a densidade vascular linfática em todas as lesões estudadas sendo que os carcinomas foliculares apresentaram a maior densidade vascular sanguínea e as tireoidites...

The thyroid neoplasms are important causes of morbi-mortality. The pathogenesis of the neoplastic dissemination through the organism is a complex and intriguing process by which many malignancies spreads from a site of origin to different parts of the body, using as preferential routes the venous and lymphatic vascular systems. The expression of vascular endothelial growth factors and their receptors (VEGFs and VEGFRs) are related to tumor angiogenesis and lymphangiogenesis participating in the diagnosis, prognostic evaluation and treatment of malignant neoplasms. The role of angiogenesis and lymphangiogenesis in the pathogenesis of thyroid cancers has not been completely elucidated. The different patterns of behavior of thyroid tumors and their metastases vary with the tumoral type and have not yet been fully explored whether differences in the expression of VEGFs and VEGFRs influence tumor metastasis or determine a more aggressive behavior. In this thesis, we evaluated the immunohistochemical expression of VEGFs and VEGFRs and the blood and lymphatic vascular density in goiter, thyroiditis and follicular adenomas and in papillary and follicular carcinomas and their adjacent regions. Afterward, we correlated our findings with the clinical pathological data. We observe that there is a gradual increase in intensity of expression of VEGFs and VEGFRs from normal thyroid tissue, proliferative lesions, benign and malignant neoplasms. In carcinomas, despite the profuse expression of VEGFs and VEGFRs we detected only statistically significant correlation of VEGF-D and VEGF-R3 with a worse tumor staging in papillary carcinomas. The blood vessel density was higher than lymphatic vascular density in all lesions studied. The follicular carcinomas showed the highest blood vessel density and thyroiditis the largest lymphatic vascular density. In the papillary carcinomas a lower blood vessel density was associated with vascular invasion and the different...

Significance of AgNOR measurement in thyroid lesions.

OBJECTIVE: To evaluate the discriminating potential of AgNOR area measurement and count in thyroid tumors using static cytometry equipment. STUDY DESIGN: Slides were analyzed by a computerized system for image analysis, CAS 200 (Becton & Dickinson, U.S.A.), using the Cell Measurement computer program (CAS 200, Becton & Dickinson). The argyrophilic reaction (NORs) was evaluated with a 400-fold amplification directly from the computer monitor. RESULTS: Thirty-three cases were analyzed for AgNOR staining. The cases studied included 3 goiters, 10 follicular adenomas, 6 Hürthle adenomas, 4 follicular carcinomas, 7 papillary carcinomas, and 3 Hürthle carcinomas. A total of 6,600 nuclei were evaluated. For statistical purposes, lesions were classified as benign and malignant, and both the number and the area of counted NORs showed very similar values. The NORs median among 19 benign tumors was 1.484 (SD +/- 0.265) and of 14 malignant tumors was 1.436 (SD +/- 0.414); the NORs areas were 2.6584 (SD +/- 1.0653) and 2.3643 (SD +/- 0.6320), respectively. CONCLUSION: Our results showed that AgNOR evaluation was not a significant parameter to discriminate between malignant and benign thyroid lesions.

DNA measurements after radiation - induced tissue structure of thyroid gland of rats

INTRODUÇAO: A exposição da tireóide à irradiação está associada à alteração do componente cromossômico nessa glândula. OBJETIVO: Avaliar o conteúdo de DNA (ploidia) em glândula tireóide submetida à radiação. MATERIAL E MÉTODOS: Foram irradiadas tireóides de 75 ratos; 25 foram usados como grupo controle e não sofreram irradiação. A exposição à irradiação foi realizada com o uso de Cobalt-60 na região cervical anterior direita com espaço de 3-30cm, com anel traqueal de 2º e 6º e dose de 600 centigrays (cGY). O conteúdo de DNA (ploidia) foi obtido com o método de Feulgen-Thionin e quantificado com o aparelho CAS 200 de citometria estática. RESULTADO: Dos 92 casos, 88 (95,7 por cento) foram diplóides, independente do tempo de exposição; aneuploidia foi observada em quatro casos (4,3 por cento), somente no grupo sacrificado aos 33 dias. Oito casos foram excluídos por problemas técnicos. CONCLUSAO: A irradiação afeta muito precocemente o conteúdo de DNA nuclear levando a aneuploidia.