An update on papillary microcarcinoma

Purpose of review There is a worldwide increasing incidence of thyroid cancer, mostly due to the increased diagnosis of papillary microcarcinoma (PMC). This review examines its clinical significance and optimal treatment. Recent findings It is unclear whether or not the increase in PMC is real, or is simply due to the increased detection and diagnosis. The increase has been attributed to the widespread availability of thyroid ultrasound, with increasing numbers of clinically insignificant thyroid nodules subject to fine needle aspiration biopsy and surgical excision. An additional explanation is simply an increase in the number of routine histologic sections taken from the thyroidectomy specimens over the years. There have been two recent large clinical series with long-term follow-up highlighting the excellent prognosis of PMC. Novel research into immunohistochemical markers and advanced imaging with fluorodeoxyglucose positron emission tomography aims to identify the markers of more aggressive PMC. Management of PMC remains controversial, from observation alone to total thyroidectomy/radioiodine ablation. Summary PMC has been increasing rapidly over recent decades due to increased cervical ultrasound and increased detection in pathological specimens. There is no compelling evidence base for the management of PMC, with retrospective series highlighting the excellent prognosis.