Hobnail subtype of papillary carcinoma of the thyroid-a rare case with uncommon features.

The cytological features of the hobnail variant of papillary thyroid carcinoma may be subtle. It is important to recognize this variant because it may influence the corresponding surgical treatment and follow-up due to its aggressive nature. The hobnail subtype of papillary thyroid carcinoma is a rare entity with aggressive features. It presents extrathyroidal extension or lymph nodal metastasis in a high percentage of the cases.