SMARCB1-deficient renal medullary carcinoma without sickle cell trait: clinicopathological and molecular characteristics
10.3760/cma.j.cn112151-20241220-00860
- VernacularTitle:不伴有镰状细胞特征的SMARCB1缺陷型肾髓质癌临床病理及分子特征分析
- Author:
Huizhi ZHANG
1
;
Jun HOU
;
Xiaoqun YANG
;
Qiuyuan XIA
;
Suying WANG
;
Yifen ZHANG
;
Hong CHEN
;
Xiaohui DING
;
Heli WANG
;
Ming ZHAO
Author Information
1. 宁波市临床病理诊断中心，宁波 315021
- Publication Type:Journal Article
- Keywords:
Kidney neoplasms;
Collecting duct carcinoma;
Pathology, clinical;
Immunohistochemistry;
Molecular biology;
SMARCB1/INI1
- From:
Chinese Journal of Pathology
2025;54(8):838-844
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To investigate the clinicopathological features including immunophenotype, molecular characteristics, differential diagnosis and prognosis of SMARCB1-deficient renal medullary carcinoma (RMC) without sickle cell trait.Methods:The clinicopathological data of 12 cases of SMARCB1-deficient RMC without sickle cell trait were collected from 7 domestic institutions during the period of 2015 to 2024. Their clinical characteristics, morphological features and immunohistochemical properties were observed and analyzed. High-throughput DNA-targeted next-generation sequencing was performed, and follow-up data were gathered along with relevant literature review.Results:Among the 12 patients, 5 were female and 7 were male. The patients age ranged from 27 to 84 years with a median age of 58.5 (46.0, 71.0) years. None of them had sickle cell disease or other hemoglobinopathies. Eight cases occurred in the left kidney and 4 cases were located in the right kidney. The average maximum diameter of the tumor was 6.1 (4.0,7.5) cm, with a range of 2.0 to 14.9 cm (the median maximum diameter 5.5 cm). Histologically, the tumors showed poorly differentiated adenocarcinoma, arranged in solid and tubular patterns. Papillary structure was noted in 5 cases, cribriform structure in 3 cases, rhabdoid differentiation in 3 cases, and sarcomatoid differentiation in 2 cases. Inflammatory desmoplastic stromal reaction was observed in 8 cases, among which stromal myxoid degeneration was seen in 6 cases. Tumor necrosis was apparent in 6 cases. The tumor cells had abundant eosinophilic or clear cytoplasm and prominent nucleoli. The nuclear grading was grade 3 or 4 according to the International Society of Urological Pathology (ISUP). Immunohistochemical staining showed that the tumor cells of all 12 cases expressed PAX8 and loss of SMARCB1/INI1 protein expression, and 5 of 10 cases expressed OCT3/4. Seven samples had valid archived paraffin tissues for high-throughput DNA-targeted next-generation sequencing. The results showed that all 7 cases had pathogenic mutations in the SMARCB1 gene. The mutation sites included exon5 c.595A>T (p.K199*), exon2 c.200_207del (p.S67*), exon2 p.G69VfsTer16, exon7 c.986G>T (p.S329I), exon7 c.886A>T (p.K296*), exon6 c.635T>A (p.L212*), exon5 c.577del (p.M193Wfs16), and exon6 c.784del (p.V262Sfs5). Follow-up data were obtained for 6 of 12 patients. Among them, 1 patient had lung and bone metastases, 1 patient had liver and bone metastases and 1 patient had multiple bone metastases at the time of diagnosis; 1 patient had bone metastases 5 months after surgery. One patient died of postoperative complications 10 days after surgery, 4 patients died of tumors (the survival time ranged from 4 to 8 months), and 1 patient had no recurrence or metastasis during the 8-month follow-up after surgery.Conclusions:SMARCB1-deficient RMC without sickle cell trait is a highly aggressive and poorly differentiated renal cell carcinoma. It has similar histomorphology, immunophenotype, molecular characteristics and prognosis to RMC, which further supports that it is a sporadic subtype of RMC related to sickle cell trait.
