A Case of the Synchronous Double Cancer of the Papillary Thyroid Cancer and the Lung Adenocarcinoma Diagnosed by the Endobronchial Ultrasound-guided Transbronchial Needle Aspiration

Abstract

Background. While cases of synchronous double cancer of the thyroid cancer and lung cancer are often reported, it may be difficult to differentiate them from thyroid cancer alone with lung metastases based solely on image findings. Case. A 76-year-old woman was considered to have papillary thyroid cancer with multiple distant metastases based on computed tomography (CT) findings of calcification in the thyroid gland and multiple lung nodules as well as the results of cytology. An abnormal uptakes was detected in the hilar, mediastinal lymph nodes and bones on positron emission tomography (PET)-CT. Considering the possibility of complication with lung cancer, we performed endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) of the subcarinal lymph node. Consequently, Napsin-A, EGFR mutation-positive lung adenocarcinoma was diagnosed and synchronous double cancer of the papillary thyroid cancer (cT2N1bM0/Stage II) and lung cancer (cT4N3M1c/Stage IVB) was considered. After the administration of afatinib, the abnormal lesions except for that in the thyroid gland had regressed significantly. Conclusion. In cases of papillary thyroid cancer with hilar or mediastinal lymphadenopathy, EBUS-TBNA for those lymph nodes may be useful for differentiating synchronous double cancer of papillary thyroid cancer and lung cancer from thyroid cancer alone with lung metastases.