Thyroid metastasis revealing a lung adenocarcinoma: A case report and review of the literature

INTRODUCTION: Metastatic lung adenocarcinoma in the thyroid is very rare. The clinical presentation and the radiological findings for metastasis carcinoma are nonspecific and do not allow the distinction between metastatic lung carcinoma and primary thyroid tumor. CASE PRESENTATION: We report the case of a pulmonary papillary adenocarcinoma revealed by a thyroid metastasis in a 62-year-old and non-smoker patient with no history of cancer. DISCUSSION: Thyroid metastasis revealing a primary adenocarcinoma of lung is extremely rare. In the absence of a history of lung cancer, the histological appearance of a papillary adenocarcinoma localized in the thyroid can be misdiagnosed as a primary thyroid cancer given the non-specificity of the clinical, radiological and histological presentations. Immunohistochemical analysis and molecular studies are the gold standards for establishing the diagnosis of the primary site. CONCLUSION: In this report we aim to discuss the histological and immunohistochemical features of lung adenocarcinoma metastazing in thyroid gland through a literature review. We are also targeting to highlight the essential role of immunohistochemistry and molecular study for the confirmation of the primary pulmonary origin and to discuss therapy for patients with lung cancer metastatic in the thyroid [17].