SMARCA4-altered malignancies: Cytologic diagnostic challenges and clinicopathologic correlation.
Only 12% of SMARCA4-altered malignancies were histologically undifferentiated tumors.
SMARCA4-altered malignancies: Cytologic diagnostic challenges and clinicopathologic correlation.
SMARCA4-deficient undifferentiated tumors (SMARCA4-dUT) have been included in the latest WHO classification of tumors.
This study examined the cytomorphology, management, molecular features and prognosis of malignancies harboring SMARCA4 alterations.
Biopsied cytologic slides were reviewed.
Tumor origins were predominantly the lung (61%) and gallbladder (9%).
The most common tumor type was adenocarcinoma (70%).
Nuclear grade 2-3 was seen in 93% of cases, with prominent nucleoli and coarse chromatin.
Prognosis is further modulated by allelic status (biallelic vs. monoallelic vs. subclonal), and mutations in DDR pathway (24%).
SMARCA4-altered malignancies show diverse differentiation and lack consistent cytomorphologic features.
Majority of cases were differentiated malignancies and only four cases (12%) were undifferentiated, suggesting SMARCA4 alterations were associated with poor prognosis but were not exclusive drivers of undifferentiated malignancy.