Occult Papillary Thyroid Carcinoma Presenting as Cystic Lateral Neck Swelling. Case Series and Review of Literature.

Background: Up to 85% of thyroid carcinoma cases are papillary thyroid cancers. It may be the only or initialsymptom of the disease, undergoing cystic transformation and manifesting as lateral neck metastases or regionallymph nodes from an unknown primary source.Patients and methods: Between January 2020 and May 2023, five individuals exhibiting a lateral cervical swellingin conjunction with a clinically unremarkable thyroid gland were managed within the surgical oncology divisionof the general surgery department at Tanta University Hospital, Egypt. A mass was found in the supraclaviculararea in two patients, the mid-anterior border of the right sternomastoid muscle region in one case, and thesubmandibular region in two cases. In all cases, there were no detectable thyroid gland masses. The clinicalexamination revealed no enlargement of the thyroid gland. The patients underwent indirect laryngoscopy, free T3,free T4, fine needle aspiration cytology (FNAC), neck ultrasonography, and CT scan.Results: Sub-centimetric nodules were found in two cases with non-suspicious cervical lymph nodes, while theneck ultrasonography and CT scan revealed cystic swelling and a normal thyroid gland in three cases. In twocases, the FNAC revealed benign cells consistent with a branchial cyst; in one case, it revealed a parotid tail tumor;in the final two cases, it revealed malignant cells. The indirect laryngoscope, TSH, free T3, and free T4 were allnormal. In every case, the histology revealed occult metastatic papillary thyroid cancer that had spread to a cysticlymph nodal tissue. The patients had radioactive iodine therapy after a modified cervical lymph node dissection inaddition to a total thyroidectomy.Conclusion: while addressing a cystic lesion in the neck, surgeons should take into account the potential for nodalmetastases from hidden malignancies, this condition may be attributed to pathologies such as papillary thyroidcarcinoma.