Lymphatic Invasion in Bethesda VI Papillary Thyroid Microcarcinomas: A Single-Center Retrospective Analysis

Öz

ABSTRACT Objective: Although small size in papillary thyroid microcarcinomas is generally associated with low risk, it may not reflect the biological behavior of the tumor. In this study, the effect of lymphatic invasion on metastatic risk and the metastatic characteristics of microcarcinomas with lymphatic invasion compared to macrocarcinomas were evaluated in a cohort with Bethesda VI diagnosis. Materials and Methods: A total of 116 patients with Bethesda VI cytology were categorized into papillary microcarcinoma (n=35) and papillary macrocarcinoma (n=81) groups. Lymphatic and vascular invasion were evaluated separately. Risk factors for central lymph node metastasis and inter-group metastatic burden were compared. Results: Vascular invasion was significantly more frequent in papillary macrocarcinomas (p=0.035), whereas lymphatic invasion rates were similar between the groups (p=0.385). In the papillary microcarcinoma group undergoing lymph node dissection, a significant association was detected between the presence of lymphatic invasion and central metastasis (p<0.001). Tumor size and multifocality were found to be non-significant in predicting metastasis. In the analysis performed, no difference was observed between the number of metastatic lymph nodes in lymphatic invasion-positive papillary microcarcinomas and macrocarcinomas (5.2 vs 4.9; p=0.597). A metastatic case with a 5 mm tumor size supported the independence of the aggressive phenotype from tumor size. Conclusion: Since the presence of lymphatic invasion in papillary microcarcinomas suggests that the tumor’s metastatic potential may be elevated to a level similar to that of macrocarcinomas, considering a more cautious strategy in the clinical management of these cases may be beneficial. However, due to the limited sample size, these findings are hypothesis-generating rather than definitive and should be validated in larger cohorts. Keywords: Papillary thyroid microcarcinoma, Bethesda VI, lymphatic invasion, central lymph node metastasis

Anahtar Kelimeler

• Papillary thyroid microcarcinoma
• Bethesda VI
• lymphatic invasion
• central lymph node metastasis

Bethesda VI Papiller Tiroid Mikrokarsinomlarında Lenfatik İnvazyon: Tek Merkezli Retrospektif Değerlendirme

Öz

ÖZET Amaç: Papiller tiroid mikrokarsinomlarında küçük boyut genellikle düşük riskle ilişkilendirilse de tümörün biyolojik davranışını yansıtmayabilir. Bu çalışmada, Bethesda VI tanılı kohortta; lenfatik invazyonun metastatik risk üzerindeki etkisi ve lenfatik invazyonu olan mikrokarsinomların makrokarsinomlar ile metastatik özellikleri değerlendirildi. Gereç ve Yöntem: Bethesda VI sitolojili 116 hasta, papiller mikrokarsinom (n=35) ve papiller makrokarsinom (n=81) olarak ayrıldı. Lenfatik ve vasküler invazyon ayrı ayrı değerlendirildi. Santral lenf nodu metastazı risk faktörleri ve gruplar arası metastatik yük açısından karşılaştırıldı. Bulgular: Vasküler İnvazyon papiller makrokarsinomlarda daha sıktı (p=0.035), ancak Lenfatik İnvazyon oranları gruplar arasında benzerdi (p=0.385). Santral Lenf nodu diseksiyonu yapılan papiller mikrokarsinom grubunda lenfatik invazyon varlığı ile santral metastaz arasında anlamlı ilişki saptandı (p<0.001). Boyut ve multifokalite metastazı öngörmede anlamsız bulundu. Yapılan analizinde; lenfatik invazyon pozitif papiller mikrokarsinomlar ile makrokarsinomların metastatik lenf nodu sayıları arasında fark izlenmedi (5.2 vs 4.9; p=0.597). 5 mm’lik metastatik olgu, agresif fenotipin boyuttan bağımsızlığını destekledi. Sonuç: Papiller mikrokarsinomlarda lenfatik invazyon varlığının, tümörün metastatik potansiyelini makrokarsinomlarla benzer bir düzeye taşıyabileceği düşünüldüğü için; bu olguların klinik yönetiminde daha temkinli bir stratejinin göz önünde bulundurulması yararlı olabilir. Ancak, sınırlı örneklem boyutu nedeniyle bu bulgular kesin sonuçlardan ziyade hipotez oluşturucu niteliktedir ve daha geniş kohortlarda doğrulanmalıdır. Anahtar Kelimeler: Papiller tiroid mikrokarsinomu, Bethesda VI, lenfatik invazyon, santral lenf nodu metastazı

Anahtar Kelimeler

• Papiller tiroid mikrokarsinomu
• Bethesda VI
• lenfatik invazyon
• santral lenf nodu metastazı

Kaynakça

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