Prevalence of Papillary Thyroid Carcinoma Difference in Pathologic Features and Tumor Capsule

  • Introduction: There is a recent shift toward performing a thyroid lobectomy in patients with a preoperative diagnosis of Papillary Thyroid Carcinoma (PTC) when certain criteria are met. PTC has a tumor capsule which can be intact, absent (AC), incomplete (ICC) or with invasion (CI) as described by the pathologist. The American Thyroid Association does not provide guidelines for the need of completion thyroidectomy when only these features are present1. While the prognostic significance of other unfavorable pathologic features have been evaluated, there is a scarcity of studies referring to tumor capsule status2,3. The purpose of our study is to evaluate the prevalence of different pathologic features related to the tumor capsule in patients with PTC. 

    Methods: Retrospective study. Included patients with a final pathology of PTC. We then evaluated the pathologic features associated with tumor capsule and classified them into two subgroups: intact capsule (TC-), and altered capsule (TC+) which includes AC, ICC and CI. We then identified presence or absence of unfavorable features (UF+ or UF-) in each of the subgroups. UF are angio-lymphatic invasion, perineural invasion, extra thyroidal extension, multifocality, and lymph node metastasis. 

    Results: 276 patients were included. Histologic presence of TC- and TC+ were 73.91% (204/276) and 26.09% (72/276), respectively. Prevalence of UF- within TC- and TC+ were of 41.67% (115/276) and 12.68% (35/276), respectively. In the TC+/UF- group, the most prevalent was AC 57.1% (20/35), reaching statistical significance with a p-value <0.01. 

    Conclusion: Almost 13% of patients with PTC can present with only an altered capsule finding on permanent pathology. This group of patients deserves to be further studied to determine optimal management.

 

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