Thyroid Cancer in Thyroglossal Duct Remnants: Case Series and Extensive Review of the Literature

펼치기

Purpose: Thyroglossal duct cysts (TGDC) are rarely malignant (1%-3%). We performed a systematic review incorporating data from patients operated for malignant TGDC reported in literature and describe an additional case from our clinics. Methods: Three databases were searched for manuscripts including TGDC cancers, regarding patient demographics, imaging, pathology, and therapeutic methods. We included data from our cohort and articles found in PubMed, PubMed Central and Cochrane. Results: We included 372 articles reporting 1,842 cases of TGDC, 628 with malignant histology: 544 papillary thyroid cancer, 28 squamous cell cancer, 9 follicular thyroid cancer and 36 various subtypes/mixed histology; 10 (1.59%) presented with distant metastasis, 120 (19.2%) with lymph node infiltration, 138 (21.9%) with capsule invasion, 120 (19.1%) with extrathyroidal extension. An analysis looking at data exclusively from case series, comprising ≥15 patients (cancer and benign histology) included three studies with 827 patients and 86 (10.4%) had TGDC cancer. The mean age for cancer patients was 39.77±13.24 years, 23 (28.0%) had affected lymph nodes, 14 (29.8%) had capsular invasion, in 4 (4.9%) the malignancy recurred and in 37 (48.7%) there was extrathyroidal extension. The average tumor size was 1.5±0.8 cm in cancerous and 1.6±1.4 cm in non-cancerous lesions. Our cohort included one patient with papillary thyroid carcinomas. Conclusion: Thyroglossal duct cyst cancers affect both genders almost equally. Cancer patients are older and mostly treated with the Sistrunk procedure. Distant metastases are rare, but other features of tumor aggressiveness are more common. The epidemiology of various histological types is almost identical to that of thyroid cancer.