Unusual metastases from tall cell variant of papillary thyroid cancer

Background: Tall cell variant (TCV) cancer is considered more aggressive than the classic variant of papillary thyroid cancer (PTC). Distant metastases are more common among this variant and affect survival. Little is known about the molecular pattern of this histotype. Methods: This is a report of 2 cases of unusual metastases from TCV, BRAF V600E-positive. Results: A 38-year-old woman developed subcutaneous metastases during short-term follow-up; at medium-term follow-up, the patient showed detectable stimulated serum thyroglobulin without disease evidence at imaging. A 33-year-old man presented incidental thymic metastases at time of surgical treatment; this is the first case of not ectopic thymic metastases from PTC. Conclusion: TCV may present with unusual metastases already during early follow-up. The more aggressive behavior could be linked to the higher prevalence of BRAF point mutations, but only a long-term follow-up might clarify if this association could worsen the prognosis. Moreover, skin metastases have been predictive factors of worse outcome in our patients, but not thymic metastases.