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follicular thyroid carcinoma

Etiology: -> iodine deficiency may play a role Epidemiology: 1) 10-20% of thyroid cancers 2) most commonly occur in the 5th to 6th decade of life 3) female/male predominance of 3/1 Pathology: 1) encapsulation is typical, making differentiation from follicular thyroid adenoma difficult* 2) relatively uniform, orderly cuboidal cells surrounding occasionally colloid-filled follicles 3) microscopic invasion through the capsule may result in distant metastases 4) vascular dissemination predominates over lymphatic spread * Much ado about removing the name 'cancer' from noninvasive encapsulated follicular variant of papillary thyroid carcinoma which seems to amount to follicular thyroid adenoma versus follicular thyroid carcinoma [3] Immunohistochemistry: - thyroglobulin + - TTF1 + - vimentin + Genetics: - implicated genes: TSHR Clinical manifestations: 1) slowly enlarging, painless thyroid nodules (most common presentation) 2) may present with metastases to the lung or bone -> functioning metastatic cancer may rarely present as thyrotoxicosis Laboratory: - serum thyroglobulin may be used as a marker for residual or recurrent disease Radiology: -> more differentiated lesions may take-up radiolabeled iodine Differential diagnosis: - follicular thyroid adenoma Management: 1) total thyroidectomy with lymph node dissection 2) radio-iodine ablation of remnant thyroid tissue following surgery 3) encapsulated lesions without capsular invasion may be surgically resected, resulting in cure 4) prognosis: a) overall 5 year survival 92% [2] b) larger, invasive cancers show 30% 5-year survival, 20% 10-year survival 5) follow-up evaluation for recurrence requires a) discontinuation of levothyroxine b) allowing the TSH to rise c) measuring serum thyroglobulin as a marker for residual thyroid tissue

Interactions

disease interactions

Related

chromosomal translocation t2q13:3p25 (follicular thyroid carcinoma) follicular thyroid adenoma

General

adenocarcinoma thyroid carcinoma

References

  1. Cotran et al Robbins Pathologic Basis of Disease, 5th ed. W.B. Saunders Co, Philadelphia, PA 1994 pg 1138
  2. Medical Knowledge Self Assessment Program (MKSAP) 11, 14, 15, 17, 18. American College of Physicians, Philadelphia 1998, 2006, 2009, 2015, 2018.
  3. Nikiforov YE, Seethala RR, Tallini G et al Nomenclature Revision for Encapsulated Follicular Variant of Papillary Thyroid Carcinoma. A Paradigm Shift to Reduce Overtreatment of Indolent Tumors. JAMA Oncol. Published online April 14, 2016 PMID: 27078145 http://oncology.jamanetwork.com/article.aspx?articleid=2513250 - Patel KN Noninvasive Encapsulated Follicular Variant of Papillary Thyroid "Cancer" (or Not)Time for a Name Change. JAMA Oncol. Published online April 14, 2016 PMID: 27077657 http://oncology.jamanetwork.com/article.aspx?articleid=2513246