Papillary thyroid carcinoma (PTC) is the most common primary malignant neoplasm of the thyroid gland and, when confined to the thyroid, often keeps an indolent course with good patient prognosis [1]. However, though unusual, distant metastases can occur and, when identified, are typically observed in bone and lung [1]. The presence of such distant metastases portends a worse outcome with severely reduced patient survival rates [2], [3].

While follicular carcinoma of the thyroid exhibits hematogenous spread and is not infrequently identified as metastatic tumor within the central nervous system, the identification of brain metastases of PTC origin is very rare, comprising only 0.1–5% of cases of brain metastases of differentiated thyroid carcinoma [4], [5]. Many studies have explored the risk factors for such disseminated cases citing male sex, older age, and extrathyroidal extension (ETE) as possible associated influences [6], [7].

Here we present all cases of metastatic PTC to brain identified within the pathology archives at our institution with a careful and comprehensive analysis of patient demographics, histologic features of both primary and metastatic tumors, molecular features, and patient outcomes. We found that all cases in our archives demonstrate aggressive histologic variants within the brain metastases. Likewise, where evaluable, the primary tumors from which these metastases arose similarly demonstrate unfavorable morphologic subtypes of PTC. Thus, our study accentuates how imperative it is to accurately report histologic variant in the pathology report in order to better predict tumor course and patient outcome.