Lung adenocarcinoma and pulmonary metastases coexist in a patient with papillary thyroid carcinoma: A case report.

RATIONALE: Multiple primary malignant tumors (MPMTs) are defined as 2 or more independent primary malignancies of different histologies/origins in the same individual. Although the incidence of MPMTs is being increasing, second primary cancer (SPC) is still rare and difficult to distinguish from metastasis. Here, we present a case of thyroid carcinoma with lung metastasis and primary lung cancer.

PATIENTS CONCERNS: The patient was a 66-year-old man diagnosed of papillary thyroid carcinoma (PTC) with lymph nodes, lung, and skeletons metastases. One of the pulmonary nodules had contrary manifestations, such as, noniodine avid, high uptake of F-fluorodexyglucose (F-FDG) and progress after iodine-131 radioiodine therapy.

INTERVENTIONS: CT guided biopsy and I-125 seed brachytherapy of nodule in right upper lobe were performed.

DIAGNOSIS: The patient was diagnosed of PTC with lymph nodes, lung, and skeletons metastases, accompanied by primary lung adenocarcinoma.

OUTCOMES: After 2 years of follow-up, nodules of inferior lobes almost disappeared and the nodule of right upper lobe shrank to only 0.7 cm.

LESSONS: Physicians should be aware of SPC in clinical work, and improve the early diagnosis rate with a variety of examination methods and select the best treatment to improve the prognosis of patients.