Warthin-like variant of papillary thyroid carcinoma with lymph node metastases: a case report and review of the literature.

[BACKGROUND] We present a rare case of thyroid lesion marked as the Warthin-like variant of papillary thyroid carcinoma (WLV-PTC) with lymph node metastases. A proper preoperative identification is difficult because of unspecific cytology features and common ultrasound characteristics of this malignant tumor. The long-term prognosis cannot be thoroughly described due to the scarcity of data. The purpose of the presentation is to show common characteristics and long-term survival rates of an uncommon variant of differentiated thyroid cancer (DTC). Therefore, the data represented in this article can make a significant contribution to future investigations.

[CASE PRESENTATION] A 40-year-old Ukrainian woman had a lesion in the thyroid gland, which was accidentally diagnosed during medical checkup. Ultrasound (US) features were similar to the common suspicious nodule. It had typical signs of suspicion for malignancy (TI-RADS-4) on the background of thyroiditis. A thorough investigation of the neck showed lymph nodes with nonspecific US features on both lateral compartments. Lymph nodes were hypoechoic, oval-shaped and 10 mm wide, with regular contours, low central vascularity, with preserving hilar fat, without cystic formation. The patient did not have any complaints or changes in the hormone status. No hereditary findings linked with cancer were discovered. The woman had been living for a long time in the country with a high level of insolation, which was atypical for the ordinary environment of the patient. Fine-needle aspiration (FNA) of the lesion was done and the Bethesda system 6 result was obtained. Total thyroidectomy with central lymph node dissection was accomplished. The histological conclusion was WLV-PTC on the background of lymphocytic infiltration of the gland with metastasis to the lymph nodes. The inpatient radioactive iodine (RAI) ablation (100 mCi) was subsequently performed. Hormone withdrawal was used followed by RAI. In one year after the surgery the level of thyroglobulin (Tg) was 0.2 ng/ml. Up to the present time the five-year follow-up has not demonstrated any signs of recurrence relying on a level of Tg (< 0.04 ng/ml), Tg antibodies (< 14 IU/ml), neck US without any structural disease.

[CONCLUSION] WLV-PTC resembles salivary gland tumors with similar histological features. This variant is not well known, but often associated with a stroma lymphocytic infiltration and a low risk of lymph node metastases. It is regarded that this rare subtype has similar long-term survival rates as classic papillary thyroid cancer (PTC).