Occult Multifocal Thyroid Papillary Carcinoma with Cystic Lymph Nodes Metastases

Background: Papillary thyroid microcarcinoma presenting as cystic lymphadenopathy as a first and sole sign has rarely been reported. When the nodal metastasis is cystic, with no apparent suspicious thyroid mass on ultrasound (US) it may be misdiagnosed as benign cystic masses. An accurate pre-operative diagnosis is essential since the management of these two conditions is different. Case report: A 32-year-old woman was referred to our endocrinology outpatient clinic for evaluation of a neck mass. Ultrasonography (USG) showed 3 lymph nodes, the largest one being 6×19×22 mm (conglomerate lymphadenopathy) in size with a cystic component divided by septa, a complex echo, microcalcifications and undistinguishable echogenic hilum, in the right side adjacent to the carotid artery. However, the thyroid USG has not revealed any abnormality. USG-guided fine-needle aspiration cytology of the cystic lymph node was performed, and cytomorphological findings confirmed a papillary carcinoma derived from the thyroid gland. The patient underwent total thyroidectomy with right lateral and central lymph node dissection. Postoperative histopathology evaluation revealed 3 papillary microcarcinomas in the right lobe, the largest one being 0.4 cm in size and 2 metastatic lymph nodes. Conclusion: Ultrasound-guided FNA is a critical step in lymph node metastases. If lymph node FNA cytology and/ or needle wash specimens confirm thyroid cancer metastases, total thyroidectomy with central lymph node dissection would be appropriate even if ultrasound did not detect any lesion in the thyroid gland as in the presented case.