27 September 2025
: Case report 
SMARCA4-Deficient Undifferentiated Carcinoma: A Report of 2 Cases
Rare disease
Sa-Hong Kim ABDEF 1,2, Kyoyoung Park D 1,2, Jane Chungyoon Kim D 1,2, Jeesun Kim D 1,2, Do-Joong Park D 1,2,3, Hyuk-Joon Lee D 1,2,3, Han-Kwang Yang D 1,2,3, Yoonjin Kwak ABDEF 4,5, Seong-Ho Kong ABDEF 1,2,3*DOI: 10.12659/AJCR.949989
Am J Case Rep 2025; 26:e949989
Figure 2 Histologic and immunohistochemical features of SMARCA4-deficient undifferentiated carcinoma from endoscopic biopsy (Case 1)(A) Hematoxylin and eosin staining shows a poorly cohesive malignant tumor composed of round-to-epithelioid cells with solid growth pattern and no evidence of glandular or squamous differentiation. (B) The tumor cells are negative for cytokeratin (AE1/AE3). (C) Immunohistochemistry reveals complete loss of BRG1 expression in tumor cells, with retained expression in background stromal elements.