MERITS OF THE PMiT (PAPILLARY MICROTUMOR) TERMINOLOGY IN THE DEFINITION OF INDICENDAL PAPILLARY CARCINOMAS OF THE THYROID: EXPERIENCE OF FIFTY CASES

Background: The term “papillary thyroid microcarcinoma (PTMC)” is generally employed to designate an incidental papillary carcinoma measuring 1 cm or less witch manifests extremely indolent behaviour. PTCMs are often detected by chance in thyroids removed for benign clinical nodules or widespread processes. There has been an exponential increase in the detection of PTCMs thanks to the recent improvement and application of ultrasonography in the management of thyroid lesions. However, no definitive treatment guideline has been developed to indicate how best to treat and manage these small tumours. For this reason the surgeon and patients may become alarmed when the pathologist reports the presence of PTMC and this may lead to re-operation, radical dissection of the neck or extensive irradiation, all of which are deemed unnecessary. On the other hand, the pathologist is concerned in defining as a “carcinoma” a lesions which he considers benign. For these reasons, Rosai et al proposed the term Papillary Microtumour of the thyroid (PMiT) during the 12th Annual Cancer Meeting in Porto (2003) and reported strict definition criteria for such entities. Methods: Since 2003, we have adopted, the Porto proposal criteria for PMiT in agreement with clinicians and surgeons. Here we report a series of 50 consecutive cases designed as PMiT (during the interval from March 2003 to August 2007) collected and treated at Molinette Hospital, University of Turin. Results: Patients (39F 11 M, median age 55.3 years) underwent to total thyrodectomy (47/50) or to lobectomy (3/50). No further treatment was performed. At histology, PMiT are often associated with benign nodules (19/50) or diffuse hyperplasic goitre (29/50), more rarely to parathyroid adenoma (1/50) and Thymoma B1 (1/50). All patients are alive and well after a median of 31.6 months follow-up (range from 5 to 57 months). Conclusions: In our experience this terminology, is well accepted by both clinicians and patients, since it decreases the danger of over-treatment, minimizes the psychological anxiety engendered by a diagnosis of carcinoma, and maintains the patient’s eligibility for life insurance unalterated.