Encapsulated papillary thyroid carcinoma: A clinico-pathologic study of 106 cases with emphasis on its morphologic subtypes (histologic growth pattern) Journal Article

  

Authors:	Rivera, M.; Tuttle, R. M.; Patel, S.; Shaha, A.; Shah, J. P.; Ghossein, R. A.
Article Title:	Encapsulated papillary thyroid carcinoma: A clinico-pathologic study of 106 cases with emphasis on its morphologic subtypes (histologic growth pattern)
Abstract:	Background: Encapsulated papillary thyroid carcinoma (EPTC) can have a histologic growth pattern similar to the one seen in classical papillary thyroid carcinoma (PTC) or akin to the follicular variant of PTC (FVPTC). This study aims to assess the behavior of EPTC according to its growth pattern. Methods: All cases of thyroid carcinomas treated at our institution between 1980 and 2000 were reviewed and reclassified according to current histopathologic criteria. Results: After review by two pathologists, 106 cases were included. Forty-three (41%) of the cases were identified as encapsulated classical PTC (E-CPTC) and 63 (59%) as encapsulated FVPTC (E-FVPTC). E-FVPTC had a higher rate of vascular invasion (16/63; 25%) than E-CPTC (2/43; 5%) (p = 0.007). In contrast, E-CPTC had a higher frequency of capsular invasion (28/43; 65%) than E-FVPTC (24/63, 38%) (p = 0.01). The lymph node metastatic rate was significantly higher in E-CPTC (11/43, 26%) compared to E-FVPTC (2/63, 3%) (p = 0.0014). All 34 noninvasive E-FVPTC lacked evidence of nodal metastases while 4 of 15 (27%) noninvasive E-CPTC presented with nodal disease (p = 0.006). Distant metastasis occurred only in four cases of E-FVPTC at presentation. These four FVPTC had extensive capsular and/or vascular invasion and no nodal disease. None of noninvasive EPTC recurred, including 30 patients treated by lobectomy without radioactive iodine (RAI) therapy (median follow-up: 8.9 years). Conclusion: E-CPTC resembles classical PTC in its propensity to metastasize to lymph nodes and its vascular/capsular invasive pattern while E-FVPTC behaves more like follicular carcinoma/adenoma group of tumors. Meticulous search for capsular and vascular invasion can reliably predict the metastatic potential of E-FVPTC but not of E-CPTC. The latter can therefore be treated like unencapsulated classical PTC. Noninvasive E-FVPTC could be managed like minimally invasive follicular carcinoma by lobectomy without RAI therapy. Invasive E-FVPTC seem quite indolent if no distant metastases are found at presentation. © Copyright 2009, Mary Ann Liebert, Inc.
Keywords:	adult; controlled study; human tissue; treatment outcome; aged; aged, 80 and over; middle aged; retrospective studies; major clinical study; clinical feature; histopathology; cancer growth; follow up; lymph node metastasis; lymphatic metastasis; cell structure; tumor volume; carcinoma, papillary; medical record review; retrospective study; distant metastasis; radioactive iodine; thyroidectomy; neoplasm invasiveness; thyroid carcinoma; thyroid neoplasms; papillary carcinoma; thyroid gland; adenocarcinoma, follicular; adenocarcinoma, papillary; follicular carcinoma
Journal Title:	Thyroid
Volume:	19
Issue:	2
ISSN:	1050-7256
Publisher:	Mary Ann Liebert, Inc
Date Published:	2009-02-01
Start Page:	119
End Page:	127
Language:	English
DOI:	10.1089/thy.2008.0303
PUBMED:	19191744
PROVIDER:	scopus
DOI/URL:	http://www.scopus.com/inward/record.url?eid=2-s2.0-59649088294&partnerID=40&md5=ba366895282c567d66eae83b643f50cf
Notes:	--- - "Cited By (since 1996): 5" - "Export Date: 30 November 2010" - "CODEN: THYRE" - "Source: Scopus"

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