30 June 2026
: Case report 
Delayed Thyroid Metastasis of Lung Adenocarcinoma Mimicking Primary Thyroid Carcinoma: A Case Report
Challenging differential diagnosis, Rare coexistence of disease or pathology
Yen Thi Le
AD 1, Hau Xuan Nguyen ADF 2,3,4*, Thai Hong Le BCE 1, Anh Tuan Doan Van BCEF 2, Duong Thai Pham BCE 3, Tuan Minh Vu BCE 3, Hoang Van Nguyen BCE 2
DOI: 10.12659/AJCR.952744
Am J Case Rep 2026; 27:e952744
Figure 2 Immunohistochemical analysis demonstrated strong nuclear positivity for Thyroid Transcription Factor-1 (TTF-1, clone SPT24, Dako) (A), diffuse cytoplasmic positivity for Napsin A (clone IP64, Cell Marque) (B), and positivity for Cytokeratin 19 (CK19, clone RCK108, Dako) (C) in tumor cells (original magnification ×200). Positive tumor cells exhibiting brown immunoreactivity are indicated (black arrows).