Introduction: Papillary thyroid carcinoma (PTC) is the most common thyroid malignancy. It typically spreads through cervical lymph nodes (LNs). Distant metastases only occur in a minority of cases, and cutaneous involvement is rare (<1%). The coexistence of skin and lung metastases without nodal spread is exceptionally rare. Hereby, we report a PTC case initially presenting as a solitary subcutaneous nodule and a later diagnosed pulmonary nodule without central neck LN involvement. Case presentation: A 59-year-old woman was presented with a painless, firm, and mobile subcutaneous nodule on the anterior neck. Excisional biopsy revealed metastasis of classic PTC. Ultrasound identified TIRADS 5 nodules in the thyroid. Fine needle aspiration biopsy (FNAB) confirmed Bethesda VI. CT imaging detected a solitary small nodule at the right lower lobe of lung. The patient underwent total thyroidectomy with central compartment dissection. Histopathology confirmed multifocal classic PTC with extrathyroidal extension and yet no LN metastasis. Staging was IVb. Adjuvant radioactive iodine therapy was conducted. The patient remains disease-free under TSH suppression after 12 months of follow-up. Informed consent was obtained from the patient. Clinical discussion: This presentation introduces an atypical dissemination of PTC with bypassing regional lymphatic pathways. Awareness of such patterns is essential for avoiding misdiagnosis and ensuring accurate staging and optimal management. In addition, comprehensive evaluation and adherence to the NCCN and AJCC guidelines are key to achieving favorable outcomes. Conclusion: This study supports the theory that PTC may metastasize via alternative routes rather than the classic lymphatic way.
Rahimi-Movaghar et al. (Fri,) studied this question.