title: Simultaneous medullary carcinoma and differentiated thyroid cancer. Case report.
abstract: BACKGROUND
  Medullary thyroid cancer (MTC) is an uncommon and aggressive tumour representing only 5-10% of all thyroid malignancies. MTC arises from parafollicular thyroid cells (C-cells) producing calcitonin hormone. Differentiated thyroid cancer (DTC) is the most frequent thyroid tumour (papillary or follicular), representing 80% of all thyroid cancer. DTC derives from follicular thyroid cells, that come from the central thyroid sketch. The association between medullary and papillary thyroid cancer is rare. Several cases have been reported of mixed carcinomas.
  
  
  METHODS
  We report two cases of associated medullary and papillary carcinomas in two different foci in patients with respectively Graves' disease and multinodular goiter. A young woman affected by Grave's disease and multinodular goiter under pharmacological treatment with antithyroidal drugs underwent total thyroidectomy. The histopathological examination revealed the presence of a medullary carcinoma of the middle third of right lobe (1.1 cm) with an adjacent papillary microcarcinoma (0.5 cm). A 72-years-old woman, affected by euthyroid multinodular goiter, underwent total thyroidectomy. The pathological findings were two microcarcinomas, medullary (0.44 cm) in the left lobe and papillary (0.22 cm) in the right lobe.
  
  
  CONCLUSIONS
  We can speculate that this coexistence is inferred, not having shown a specific cause that justifies the association between the two types of tumour and the high prevalence of papillary carcinoma.
authors.affiliation: Emdocrine Surgery Unit, Department of Surgical Sciences Organ Transplant and Advanced Technologies, University of Catania, Italy. mario.costanzo@unict.it
authors.forename: Mario
authors.initials: M
authors.lastname: Costanzo
authors.forename: Alessia
authors.initials: A
authors.lastname: Marziani
authors.forename: Vanessa
authors.initials: V
authors.lastname: Papa
authors.forename: Maria Concetta
authors.initials: MC
authors.lastname: Arcerito
authors.forename: Matteo Angelo
authors.initials: MA
authors.lastname: Cannizzaro
mesh_terms: D000328:Adult; D000368:Aged; D018276:Carcinoma, Medullary / Q000175:diagnosis; D002291:Carcinoma, Papillary / Q000175:diagnosis; D005260:Female; D006801:Humans; D009378:Neoplasms, Multiple Primary / Q000175:diagnosis; D013964:Thyroid Neoplasms / Q000175:diagnosis