Collision tumors of the thyroid. A special clinical and pathological entity

Andreea Bojoga, Laura Stănescu, Corin Badiu


Thyroid collision tumors are rare entities that designate two histologically and morphologically distinct tumors that occur simultaneously or as metastases from other organs within the thyroid. Medullary and papillary carcinoma co-occurrence is the most frequent. Several theories tried to explain the pathogenic mechanisms underlining collision tumors, including the theory which assumes that one tumor predisposes the other, stem cell theory, and random effect theory, but their combination better explains the origin of these tumors. Hypotheses about common genetic behavior responsible for the pathogenesis have also been suggested, such as the involvement of germline mutation of RET (Rearranged during Transfection) proto-oncogene in medullary thyroid carcinoma and papillary thyroid carcinoma coexistence, but there is controversy on this topic. Management of thyroid collision tumors is challenging owing to the presence of two distinct tumors with different biological aggressiveness, treatments options, and prognosis, and needs to be individualized.


cancer; thyroid; collision tumors

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Brandwein-Gensler M, Urken M, Wang B. Collision tumor of the thyroid: a case report of metastatic liposarcoma plus papillary thyroid carcinoma. Head Neck. 2004; 26(7):637-641.

Thomas A, Mittal N, Rane SU, et al. Papillary and medullary thyroid carcinomas presenting as collision tumors: a case series of 21 cases at a tertiary care cancer center. Head Neck Pathol. 2021; 15(4):1137-1146.

Volante M, Papotti M, Roth J, et al. Mixed medullary-follicular thyroid carcinoma. Am J Pathol. 1999; 155(5):1499-1509.

Walvekar RR, Kane SV, D’Cruz AK. Collision tumor of the thyroid: follicular variant of papillary carcinoma and squamous carcinoma. World J Surg Oncol. 2006; 4:65.

Plauche V, Dewenter T, Walvekar RR. Follicular and papillary carcinoma: a thyroid collision tumor. Indian J Otolaryngol Head Neck Surg. 2013; 65(Suppl 1):182-184.

Cichoń S, Anielski R, Konturek A, Barczyński M, Cichoń W. Metastases to the thyroid gland: seventeen cases operated on in a single clinical center. Langenbecks Arch Surg. 2006; 391(6):581-587.

Pastorello RG, Saieg MA. Metastases to the thyroid: potential cytologic mimics of primary thyroid neoplasms. Arch Pathol Lab Med. 2018; 143(3):394-399.

Koufopoulos N, Zacharatou A, Gouloumis A-R, et al. Metastatic thyroid osteosarcoma with concomitant multifocal papillary carcinoma presenting as a collision tumor. Cureus. 2021; 13(6):e15425.

Chung AY, Tran TB, Brumund KT, Weisman RA, Bouvet M. Metastases to the thyroid: a review of the literature from the last decade. Thyroid Off J Am Thyroid Assoc. 2012; 22(3):258-268.

Ryan N, Walkden G, Lazic D, Tierney P. Collision tumors of the thyroid: a case report and review of the literature. Head Neck. 2015; 37(10):E125-129.

Rossi ED, Pantanowitz L, Hornick JL. A worldwide journey of thyroid cancer incidence centred on tumour histology. Lancet Diabetes Endocrinol. 2021; 9(4):193-194.

Sadow PM, Hunt JL. Mixed medullary-follicular-derived carcinomas of the thyroid gland. Adv Anat Pathol. 2010; 17(4):282-285.

Biscolla RP, Ugolini C, Sculli M, et al. Medullary and papillary tumors are frequently associated in the same thyroid gland without evidence of reciprocal influence in their biologic behavior. Thyroid. 2004; 14(11):946-952.

Wong RL, Kazaure HS, Roman SA, Sosa JA. Simultaneous medullary and differentiated thyroid cancer: a population-level analysis of an increasingly common entity. Ann Surg Oncol. 2012; 19(8):2635-2642.

Rossi S, Fugazzola L, De Pasquale L, et al. Medullary and papillary carcinoma of the thyroid gland occurring as a collision tumour: report of three cases with molecular analysis and review of the literature. Endocr Relat Cancer. 2005; 12(2):281-289.

Pishdad R, Cespedes L, Boutin R, Jaloudi M, Raghuwanshi M. Coexistence of two different thyroid malignancies: a collision phenomenon. Cureus. 2020; 12(4):e7539.

Kim WG, Gong G, Kim EY, et al. Concurrent occurrence of medullary thyroid carcinoma and papillary thyroid carcinoma in the same thyroid should be considered as coincidental. Clin Endocrinol (Oxf). 2010; 72(2):256-263.

Nabili V, Natarajan S, Hirschovitz S, Bhuta S, Abemayor E. Collision tumor of thyroid: metastatic lung adenocarcinoma plus papillary thyroid carcinoma. Am J Otolaryngol. 2007; 28(3):218-220.

Toyoshima MTK, Domingues RB, Soares IC, et al. Thyroid collision tumor containing oncocytic carcinoma, classical and hobnail variants of papillary carcinoma and areas of poorly differentiated carcinoma. Arch Endocrinol Metab. 2021; 65(4):495-499.

Warman M, Lipschitz N, Ikher S, Halperin D. Collision tumor of the thyroid gland: primary squamous cell and papillary thyroid carcinoma. ISRN Otolaryngol. 2011; 2011:582374.

Soror NN, Shah P, Hemrock L, Bennett R. Primary squamous cell carcinoma of the thyroid: a case report and literature review about a rare entity. Cureus. 2021; 13(5):e14963.

Sokoya M, Thomas CM, Eustaquio M. A rare collision tumor: tracheal sarcomatoid carcinoma invading a papillary thyroid carcinoma. Open Access Libr. J 2017; 4(12):1-6.

Booya F, Sebo TJ, Kasperbauer JL, Fatourechi V. Primary squamous cell carcinoma of the thyroid: report of ten cases. Thyroid. 2006; 16(1):89-93.

Gul K, Ozdemir D, Ugras S, Inancli SS, Ersoy R, Cakir B. Coexistent familial nonmultiple endocrine neoplasia medullary thyroid carcinoma and papillary thyroid carcinoma associated with RET polymorphism. Am J Med Sci. 2010; 340(1):60-63.

Kleer CG, Giordano TJ, Merino MJ. Squamous cell carcinoma of the thyroid: an aggressive tumor associated with tall cell variant of papillary thyroid carcinoma. Mod Pathol. 2000; 13(7):742-746.

Darwish A, Satir AA, Hameed T, Malik S, Aqel N. Simultaneous medullary carcinoma, occult papillary carcinoma and lymphocytic thyroiditis. Malays J Pathol. 1995; 17(2):103-107.

Ljungberg O, Ericsson UB, Bondeson L, Thorell J. A compound follicular-parafollicular cell carcinoma of the thyroid: a new tumor entity? Cancer. 1983; 52(6):1053-1061.<1053::aid-cncr2820520621>;2-q

Gurkan E, Gurbuz Y, Tarkun I, Canturk Z, Cetinarslan B. Mixed medullary-papillary carcinoma of the thyroid: report of two cases and review of the literature. Indian J Pathol Microbiol. 2014; 57(4):598-602.

Dikbas O, Duman AA, Guvendi GF. Medullary thyroid carcinoma and papillary thyroid carcinoma in the same patient as a collision tumour. Case Rep Endocrinol. 2019; 2019:4038628.

Brauckhoff M, Gimm O, Hinze R, Ukkat J, Brauckhoff K, Dralle H. Papillary thyroid carcinoma in patients with ret proto-oncogene germline mutation. Thyroid. 2002; 12(7):557-561.

Bounacer A, Wicker R, Caillou B, et al. High prevalence of activating ret proto-oncogene rearrangements, in thyroid tumors from patients who had received external radiation. Oncogene. 1997; 15(11):1263-1273.

Ball DW. Medullary thyroid cancer: therapeutic targets and molecular markers. Curr Opin Oncol. 2007; 19(1):18-23.

Vantyghem M-C, Pigny P, Leteurtre E, et al. Thyroid carcinomas involving follicular and parafollicular C cells: seventeen cases with characterization of RET oncogenic activation. Thyroid Off J Am Thyroid Asso.c 2004; 14(10):842-847.

Weinhaeusel A, Scheuba C, Lauss M, et al. The influence of gender, age, and RET polymorphisms on C-cell hyperplasia and medullary thyroid carcinoma. Thyroid Off J Am Thyroid Assoc. 2008; 18(12):1269-1276.


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