Primary small cell neuroendocrine carcinoma of the tonsil combined with squamous cell carcinoma of the hypopharynx: a case report.

Background: Primary small cell neuroendocrine carcinoma (SCNEC) of the tonsils is extremely rare and is often misdiagnosed as squamous cell carcinoma. Cases coexisting with hypopharyngeal squamous cell carcinoma (HPSCC) have not been reported. The presence of concurrent aortic arch aneurysm further complicates treatment. Case Description: A 71-year-old male presented with pharyngeal pain lasting over one month. Imaging and pathological examinations confirmed right tonsillar SCNEC (with approximately 80% Ki-67 positivity) and left HPSCC, along with concurrent aortic arch aneurysm and stage III chronic kidney disease. Following multidisciplinary consultation, intracavitary aortic repair was performed first, followed by radical tumor resection 2 weeks later (including tonsillectomy, hypopharyngeal tumor resection, and bilateral cervical lymph node dissection). Postoperative pathology showed negative surgical margins and no lymph node metastasis. Perioperative complications included left upper limb intermuscular vein thrombosis and pulmonary infection, both of which resolved after treatment. Adjuvant radiotherapy and chemotherapy were recommended but declined by the patient and family. No recurrence was observed on laryngoscopy at 6 months postoperatively. Conclusions: Primary SCNEC of the tonsils combined by HPSCC is extremely rare. A complete diagnostic evidence chain (independent imaging findings, distinct immunophenotypes, and exclusion of pulmonary primary origin) is essential. For high-risk patients with arterial aneurysms, a multidisciplinary "addressing vascular issues first, then performing tumor resection" sequential approach can reduce perioperative risks.