Intestinal SMARCA4(BRG1)-deficient undifferentiated carcinoma:a pathological analysis and review of literature

XU Cunbao; YAO Xihu; WANG Yixuan; CHEN Yifeng

doi:10.3969/j.issn.1007-8096.2025.10.011

Abstract：Objective To investigate the clinicopathological features,immunophenotypes,diagnosis and differential diagnosis,treatment,and prognosis of intestinal SMARCA4(BRG1)-deficient undifferentiated carcinoma.Methods The clinical and pathological data from 2 cases intestinal SMARCA4(BRG1)-deficient undifferentiated carcinoma were retrospectively analyzed.HE staining and the immunohistochemical EnVision two-step method were employed to evaluate the clinicopathological characteristics,and relevant literature was reviewed.Results The tumor cells exhibited a sheet-like and diffuse growth pattern.Most tumor cells demonstrated an epithelioid morphology with vacuolated nuclei and prominent nucleoli,while a small subset showed rhabdoid morphology.Mitotic figures were easily observed.Immunohistochemically,BRG1 expression was lost;SOX2,Vim,and SALL4 were expressed to varying degrees;CK and CD34 were either positive or negative;CK20,CDX-2,and SATB2 were negative,and Ki-67 proliferation index was markedly high(approximately 80%).This carcinoma was more commonly found in males,with a median age of 62 years,and had a tendency to develop distant liver metastasis.The one-year mortality rate of patients was high,with a median survival time of about 11 months.Conclusion Intestinal SMARCA4(BRG1)-deficient undifferentiated carcinoma is a rare,poorly differentiated,and highly aggressive tumor that predominantly occurs in middle-aged and elderly males.It is prone to lymph node metastasis and distant metastasis.Treatment options include surgery,chemotherapy,immunotherapy,and targeted therapy.The disease is associated with a short median survival time and poor prognosis.