Collision tumor of invasive squamous cell carcinoma and adenoid cystic carcinoma in the oropharynx: a case report

Abstract Introduction: Primary collision tumors composed of two histologically distinct components are rare in the head and neck, its pathobiological features remain unclear. Case presentation: A man in his late 50s presented with paranesthesia pharynges and underwent upper endoscopy, followed by histopathological examination of biopsy specimens. He seems to have two tumors in the oropharynx with a size of 1.5*1.3cm, and an ulcer focus in the esophagus measuring about 1*0.8cm. Histopathological examination revealed a coexistence tumor of two components in the oropharynx, one was an adenocarcinoma with cribriform and solid growth pattern, with interstitial vitreous degeneration and central necrosis, the other was with a solid growth pattern, which was observed in both oropharynx and esophagus. The patient had a favorable outcome.Conclusion: Correct diagnosis can be challenging and is essential and beneficial for the prognosis of the patient.