Thirty synchronous medullary and papillary thyroid carcinomas

Synopsis for table of contentsAn exceptional number of synchronous MTC/PTC in the same thyroid gland is presented. This may be the most numerous case series reported in the literature. Synchronous PTC/MTC in the same thyroid gland were classified into 4 subtypes and the clinical and pathological aspects as well as the results are presented. Background and objectivesThe synchronous occurrence of multiple neoplastic processes in the thyroid gland is unusual. We investigated the clinicopathological features of 30 medullary thyroid carcinomas (MTC) in association with papillary (PTC). MethodRetrospective analysis of operated patients for thyroid tumors. Synchronous PTC/MTC in the same thyroid gland were classified into 4 subtypes: (type I) True mixed MTC/PTC, MTC and PTC closely intermingled. (Type II) Collision MTC/PTC, i.e. tumors that meet at the same site, invade each other and appear as a single mass in the thyroid gland, i.e. MTC and PTC merge. (Type III) Synchronous anatomically separate tumors in the same thyroid lobe, i.e. separated from each other by non-tumorous thyroid parenchyma. (Type IV) Synchronous tumors occurring in separate anatomical lobes or in the isthmus. Clinical and pathological data were reviewed. Location: Department of thyroid surgery, China-Japan Union Hospital, Jilin University. Time frame: 14 years (June 2008-November 2022). ResultsThirty patients were identified with an overall prevalence of 28621 (0.1%). 17 (56.7%) were male, 13 (43.3%) female, mean age 51.3 +/- 11.0 years, mean BMI 23.6 +/- 3.6kg/m(2). Mean duration of symptoms was 11.2 +/- 18.4 months. Mean calcitonin level was 133.7 +/- 196.4 pg/ml. Fine needle aspiration (FNA) was offered in 21 cases: 9 (42.9%) were suspected carcinoma, 9 (42.9%) PTC, 1 (4.8%) MTC, 2 (9.4%) MTC/PTC. Pathology revealed type I 4 (13.3%), type II 2 (6.7%), type III 14 (46.7%), type IV 10 (33.3%). The mean diameter of MTC was 1.6 +/- 2.0cm, 18 (60%) were micro-MTC. The mean diameter of PTC was 0.9 +/- 1.9 cm, 26 (86.7%) were micro-PTC. In 16 (53.3%) micro-PTC/-MTC occurred in synchronous sequence. Four patients had a recurrence: 2 had to be re-operated due to MTC recurrence, 2 died due to distant metastases (bone, liver). ConclusionWe report an exceptional number of MTC/PTC in the same thyroid gland. This may be the most numerous case series reported in the literature. The clinical and pathological aspects as well as the results are presented.