Papillary microcarcinoma of the thyroid has been described as either a normal variant or a serious malignancy. We describe our experience with papillary microcarcinoma and lymph node metastases.

A total of 685 consecutive total thyroidectomies with central compartment neck dissection were reviewed for papillary microcarcinoma. Association of central compartment lymph node metastases with age, gender, tumour multifocality, bilaterality and extrathyroidal extension was analysed.

Out of 170 papillary microcarcinoma cases, multifocality was found in 72 (42.4 per cent), bilaterality in 49 (28.8 per cent) and extrathyroidal extension in 16 (9.4 per cent). In all, 23 patients (13.5 per cent) had lymph node metastases. There was a significant association (p < 0.05) between extrathyroidal extension (but no other tumour characteristics) and lymph node metastases.

In all, 13.5 per cent of papillary microcarcinomas in our series showed lymph node metastases. Lymph node metastases were associated with extrathyroidal invasion of the papillary microcarcinoma.

The incidence of papillary thyroid cancer is rising, with an increase in the number of microcarcinomas being discovered. There is controversy in the literature regarding the optimal management of these tumours. This study aimed to review our institution's experience with the presentation and management of papillary thyroid microcarcinoma.

Retrospective analysis from the Sydney Head and Neck Cancer Institute, from 1987 to 2009.

A total of 228 patients were analysed. Papillary thyroid microcarcinomas were discovered incidentally in 116 (50.9 per cent) patients and non-incidentally in the remaining 112 (49.1 per cent) patients. Amongst the non-incidental group, 11.6 per cent of patients presented with lateral cervical lymph node involvement. Non-incidental microcarcinomas were significantly associated with younger age (<45 years) (p = 0.007) and larger tumours (5–10 mm) (p < 0.001). Only four patients in the incidental group suffered recurrent disease (locoregional). No patient developed distant metastatic disease or died during follow up.

Papillary thyroid microcarcinomas present both incidentally and non-incidentally, with equal prevalence. Non-incidental tumours not infrequently present with cervical lymph node disease. The patient outcome is generally excellent.