Granular Cell Tumor of the Bladder: A Report of Six Cases

Better characterize granular cell tumor of the bladder, with only 20 cases reported to date and unclear management guidelines.

We report 5 benign and 1 malignant granular cell tumor of the bladder.

Patient ages ranged from 33 to 73. Tumor sizes ranged from 0.2 to 6.3 cm. Two benign granular cell tumors were incidental findings with others presenting with painless hematuria. Benign granular cell tumors infiltrated the muscularis propria, and were confirmed by immunohistochemistry for S100 protein with negative stains for keratins. The malignant granular cell tumor involved the entire bladder wall with extension into peri-vesical tissue. Benign granular cell tumors were treated by transurethral resection (TUR) or partial cystectomy; all patients were disease-free at last follow-up. The malignant granular cell tumor was treated by anterior exenteration and bilateral pelvic lymphadenectomy. This patient developed pulmonary and pleural metastases two years after surgery.

Given the locally infiltrative nature of granular cell tumors and that 50% of reported benign granular cell tumors with sufficient follow-up recurred following initial TUR, it is prudent to recommend partial cystectomy if technically feasible. A later TUR at a time of tumor regrowth could result in obstruction of ureters depending on their location and with greater infiltrative growth, with larger subsequent resections be needed for complete removal. In other cases, immediate repeat TUR after a diagnosis of granular cell tumor would lessen the likelihood of local recurrence. Either partial or radical cystectomy is needed for the rare malignant granular cell tumor.

Urology. 2018 Aug 28 [Epub ahead of print]

Yue Sun, Victor E Reuter, Cristina Magi-Galluzzi, Alex Sankin, Jonathan I Epstein

Department of Pathology, Johns Hopkins Medical Institute, Baltimore, MD., Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY., Department of Pathology, Cleveland Clinic, Cleveland, OH., Department of Urology, The Albert Einstein College of Medicine & The Montefiore Medical Center, New York, NY., Departments of Pathology, Urology, and Oncology, Johns Hopkins Medical Institute, Baltimore, MD. Electronic address: .