30 July 2026
: Case report 
Thoracic SMARCA4-Deficient Undifferentiated Tumor Presenting as a Giant Mediastinal Mass: A Case Report
Challenging differential diagnosis, Rare disease, Educational Purpose (only if useful for a systematic review or synthesis)
Nanami Ichihashi ABCDEF 1, Motona Kumagai
ABCDEF 2,3*, Miyako Shimasaki BCDEF 2, Akihiro Shioya BCDEF 3,4, Sohsuke Yamada BCDEF 3,5
DOI: 10.12659/AJCR.952937
Am J Case Rep 2026; 27:e952937
Figure 3 Immunohistochemical findings of the tumor(A) Tumor cells showing diffuse positivity for CD34. (B) Complete loss of SMARCA4 (BRG1) expression in tumor cells, with preserved expression in non-neoplastic cells serving as an internal control. (C) Tumor cells showing SALL4 negativity. (D) Nuclear positivity for SOX2 in tumor cells. Abbreviations: BRG1, Brahma-related gene 1; CD34, cluster of differentiation 34; SALL4, Sal-like protein 4; SMARCA4, SWI/SNF-related matrix-associated actin-dependent regulator of chromatin subfamily A member 4; SOX2, sex-determining region Y-box 2.