Orhun Çığ Taşkın1, Ayşe Armutlu2, Orhan Ağcaoğlu3, Önder Peker4, Tarık Terzioğlu5, Mehmet Onur Demirkol6, Serdar Tezelman3, Yersu Kapran2. 1. Department of Pathology, Koç University Hospital, Turkey. Electronic address: otaskin@kuh.ku.edu.tr. 2. Department of Pathology, Koç University Hospital, Turkey. 3. Department of Surgery, Koç University Hospital, Turkey. 4. Department of Pathology, VKV American Hospital, Turkey. 5. Department of Surgery, VKV American Hospital, Turkey. 6. Nuclear Medicine and Radionuclide Therapy, Koç University Hospital, Turkey.
Abstract
OBJECTIVE: Lymph node metastasis occurs in a subset of papillary microcarcinoma patients. We aimed to analyze the differences between metastatic and non-metastatic papillary microcarcinomas in order to identify a high-risk subgroup that is likely to require more aggressive treatment. MATERIALS AND METHODS: 126 thyroidectomies with lymph node dissections (central ± lateral), diagnosed as papillary microcarcinoma, were reviewed. RESULTS: Mean age of 126 patients (F/M = 3.3) was 42 years. Mean size of the largest tumor was 7 mm. Classical was the most frequently (89%) encountered subtype. Multiple histologic subtypes co-occurred in 19%. Lymphovascular invasion was present in 16% (n = 20). 55 (44%) and 71 (56%) cases were unifocal and multifocal, respectively. 90 cases (71%) were non-encapsulated with overall infiltrative tumor borders, whereas in 36 cases (29%), the tumor had a well-defined capsule. Among those, 23 (64%) had tumor capsule invasion. 47 (37%) cases had metastasis in lymph nodes. In univariate analysis, metastasis was associated with tumor size of >5 mm (p = 0.02), tumor burden of >5 mm (p = 0.03), lymphovascular invasion (p = 0.02) and non-encapsulation (p = 0.01). No associations were found regarding sex, age, histologic subtype, lymphocytic thyroiditis, tumor capsule invasion (in capsulated tumors), laterality and multifocality (p > 0.05). In multivariate analysis, lymphovascular invasion (p = 0.01, OR = 3.97, 95% CI 1.35-11.67), tumor size >0.5 cm (p = 0.031, OR = 2.92, 95% CI 1.10-7.71) and non-encapsulation (p = 0.033, OR = 2.85, 95% CI 1.08-7.51) were independent risk factors. CONCLUSION: Size (largest tumor or sum of all foci) of >5 mm, non-encapsulation and lymphovascular invasion were independent predictors of LNM in PMs. Unifocal tumors metastasize the same as multifocal tumors, suggestive of the contribution of other factors. Patients with sporadically resected microcarcinomas should be carefully followed-up, especially those that harbor risk factors in histology.
OBJECTIVE: Lymph node metastasis occurs in a subset of papillary microcarcinomapatients. We aimed to analyze the differences between metastatic and non-metastatic papillary microcarcinomas in order to identify a high-risk subgroup that is likely to require more aggressive treatment. MATERIALS AND METHODS: 126 thyroidectomies with lymph node dissections (central ± lateral), diagnosed as papillary microcarcinoma, were reviewed. RESULTS: Mean age of 126 patients (F/M = 3.3) was 42 years. Mean size of the largest tumor was 7 mm. Classical was the most frequently (89%) encountered subtype. Multiple histologic subtypes co-occurred in 19%. Lymphovascular invasion was present in 16% (n = 20). 55 (44%) and 71 (56%) cases were unifocal and multifocal, respectively. 90 cases (71%) were non-encapsulated with overall infiltrative tumor borders, whereas in 36 cases (29%), the tumor had a well-defined capsule. Among those, 23 (64%) had tumor capsule invasion. 47 (37%) cases had metastasis in lymph nodes. In univariate analysis, metastasis was associated with tumor size of >5 mm (p = 0.02), tumor burden of >5 mm (p = 0.03), lymphovascular invasion (p = 0.02) and non-encapsulation (p = 0.01). No associations were found regarding sex, age, histologic subtype, lymphocytic thyroiditis, tumor capsule invasion (in capsulated tumors), laterality and multifocality (p > 0.05). In multivariate analysis, lymphovascular invasion (p = 0.01, OR = 3.97, 95% CI 1.35-11.67), tumor size >0.5 cm (p = 0.031, OR = 2.92, 95% CI 1.10-7.71) and non-encapsulation (p = 0.033, OR = 2.85, 95% CI 1.08-7.51) were independent risk factors. CONCLUSION: Size (largest tumor or sum of all foci) of >5 mm, non-encapsulation and lymphovascular invasion were independent predictors of LNM in PMs. Unifocal tumors metastasize the same as multifocal tumors, suggestive of the contribution of other factors. Patients with sporadically resected microcarcinomas should be carefully followed-up, especially those that harbor risk factors in histology.