Clinicopathologic characteristics of prostatic stromal sarcoma with rhabdoid features: A case report

Prostatic stromal sarcoma presenting with rhabdoid features is extremely rare, and only four cases have been reported in the English-language literature to date. Accordingly, there is no absolute definition of this group of tumors as yet, and our overall understanding of its morphological features, therapeutic regimen and prognosis is limited.

A 34-year-old male patient was referred to our hospital to address a 2-mo history of hematuria and progressive dysuria. Pelvic computed tomography scan revealed a 6.0 cm × 5.2 cm × 7.2 cm mass in the prostate, with bladder invasion. The patient underwent transurethral prostatectomy as upfront therapy. He refused further treatment and died of uncontrollable tumor growth 3 mo after surgery. Pathology analysis revealed the stroma to be pleomorphic, with a huge number of atypical spindle cells. Rhabdomyoblastic cells, with abundant eosinophilic cytoplasm, were detected. The spindle cells were positive for vimentin, INI1 and β-catenin, and the rhabdomyoblastic cells were positive for MyoD1, myogenin and INI1. The spindle cells and epithelial cells were sporadically positive for P53.

The prostatic stromal sarcoma tumor was immunoreactive for β-catenin, suggesting a role for the Wnt/β-catenin pathway in this tumor type.