title: Collision tumors of the thyroid: A case report and review of the literature.
abstract: BACKGROUND
  Collision tumors of the thyroid are a rare pathology that present a diagnostic and treatment challenge. In this report, we present an interesting case and a review of the current literature as to inform management.
  
  
  RESULTS
  An 88-year-old woman presented with acute airway compromise and vocal cord paralysis. CT identified a thyroid mass and widespread metastasis. Histopathology identified the lesion as a collision tumor consisting of a squamous cell carcinoma (SCC) and papillary thyroid carcinoma. The patient was managed with surgery and palliative radiotherapy. However, she died from complications of a lower respiratory tract infection. We also present a review of the literature with 33 cases reviewed.
  
  
  CONCLUSIONS
  Management of collision tumors is complex because of the duality of the pathology. They should be managed in a multidisciplinary team setting and treatment should be patient specific. Generally, the most aggressive neoplasm should guide treatment. We recommend surgical management with adjunct therapy.
authors.affiliation: United Bristol Healthcare NHS Trust, ENT Bristol, United Kingdom.
authors.forename: Neil
authors.initials: N
authors.lastname: Ryan
authors.affiliation: North Bristol NHS Trust, Surgery Bristol, United Kingdom.
authors.forename: Graham
authors.initials: G
authors.lastname: Walkden
authors.affiliation: Great Western Hospital, Histopathology Swindon, United Kingdom.
authors.forename: Darko
authors.initials: D
authors.lastname: Lazic
authors.affiliation: United Bristol Healthcare NHS Trust, ENT Bristol, United Kingdom.
authors.forename: Paul
authors.initials: P
authors.lastname: Tierney
mesh_terms: D000369:Aged, 80 and over; D002277:Carcinoma / Q000175:diagnosis* / Q000532:radiotherapy / Q000601:surgery; D002291:Carcinoma, Papillary; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis* / Q000532:radiotherapy / Q000601:surgery; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D000077273:Thyroid Cancer, Papillary; D013961:Thyroid Gland / Q000473:pathology*; D013964:Thyroid Neoplasms / Q000175:diagnosis* / Q000532:radiotherapy / Q000601:surgery; D013965:Thyroidectomy
keywords: cancer; collision tumor; review; surgery; thyroid