Papillary Microcarcinoma

Abstract

Papillary microcarcinoma (PMC) is increasing in incidence because of diagnosis by ultrasound-guided fine-needle aspiration cytology. Between January 1966 and December 1995, we treated 6019 patients with papillary cancer; among them, 2070 patients with PMC were studied. PMC is essentially very similar to papillary cancer that is 11 mm or larger and has a very good prognosis. Smaller tumors and younger patients have a better prognosis. Among PMC, larger tumors (6–10 mm) recur in 14% at 35 years compared with 3.3% in patients with smaller tumors. Patients older than 55 years have recurrence in 40% at 30 years, with a worse prognosis than younger patients who have a recurrence rate of less than 10%. Extracapsular invasion by the primary tumor also has a higher recurrence rate. The majority of recurrences are in the neck. Therefore, annual ultrasound of the neck is effective for recurrence surveillance. Papillary microcarcinoma is similar to larger papillary carcinomas with tumor characteristics and age-based recurrence rate that extends for many years, justifying long surveillance after surgery.