Unexpected metastasis of thyroid cartilage involvement from lung adenocarcinoma: A case report

Abstract

BACKGROUND

Thyroid cartilage noncontiguous metastatic involvement is an extremely rare entity due to the absence of vessels within the cartilaginous tissue. A literature review revealed that metastasis from lung cancer is even rarer.

CASE SUMMARY

A 51-year-old male smoker presented with progressive, painful left upper neck lumps for 8 months, accompanied by 10 kg weight loss, poor appetite, and mentation. He had a 30-year history of chronic alcohol use. Following comprehensive imaging studies and pathological examinations, we have identified metastatic lung adenocarcinoma with widespread dissemination to multiple sites including the thyroid cartilage. The final diagnosis is: Lung adenocarcinoma (pT3N3M1c, Stage IVb), epidermal growth factor receptor-mutated (p.E746_S752delinsV). After multidisciplinary team discussion, the patient was initiated on targeted therapy with gefitinib (250 mg/day). At 6-month follow-up, the patient has shown significant clinical improvement with marked reduction in subcutaneous masses in both the cervical and abdominal regions.

CONCLUSION

Monitor for uncommon thyroid cartilage noncontiguous metastases; early detection improves outcomes.

Keywords: Neck neoplasms; Thyroid cartilages; Adenocarcinoma of lung; Case report

Core Tip: This rare case documents thyroid cartilage metastasis from an epidermal growth factor receptor (EGFR)-mutated lung adenocarcinoma (p.E746_S752delinsV) in a 51-year-old smoker. Despite the avascular nature of cartilaginous tissue, the patient presented with neck masses, weight loss, and widespread metastases (pT3N3M1c, stage IVB). First-line gefitinib achieved remarkable regression of cervical, abdominal subcutaneous, and oropharyngeal lesions at 6 months. Key highlights: (1) Thyroid cartilage metastasis, though exceptionally rare, warrants vigilance in lung cancer; (2) EGFR targeting remains effective even in unusual metastatic patterns; and (3) Multidisciplinary management optimizes outcomes. Early molecular testing is critical for tailored therapy.