Leiomyoma of the Urinary Bladder: A Review and Update
Authors: Anthony Kodzo-Grey Venyo  
Published: August 2020

Leiomyoma of the urinary bladder / leiomyoma of the ureter is a very rare benign tumour of smooth muscle origin which has been reported sporadically globally. Leiomyoma of the urinary bladder/ureter may be diagnosed incidentally during investigation of various conditions including infertility and hepatitis. Leiomyoma of the urinary bladder / ureter may manifest in female as well as in a male patient with non-specific symptoms including lower urinary tract symptoms / retention of urine, haematuria, loin pain/discomfort, urinary tract infections and cystitis. The general and systematic examinations may be normal but at times there may be a palpable mass within the area of the urinary bladder on bimanual examination but not always. There may occasionally be tenderness in the loin. The results of routine haematology and biochemistry blood tests would generally tend to be normal but there may be anaemia and impairment of renal function some cases of visible haematuria and obstruction of the ureter respectively. Ultrasound scan would tend to illustrate a well-circumscribed polypoidal soft tissue mass projecting into the urinary bladder or within the intramural area of the bladder. Intravenous urography would show a filling defect in the urinary bladder. CT and MRI scans of abdomen and pelvis with contrast would show a well-defined round mass in the area of the bladder which could be iso-tense to skeletal muscles on T1 and T2 weighted images and occasionally may show cystic areas of necrosis. Cystoscopy would show the lesion projecting into the urinary bladder at the specific area of the urinary bladder involved and at times the projecting lesion would be covered by normal looking urothelial mucosa and on other occasions when the lesion is large and in the area of a ureteric orifice the specific ureteric orifice would not be visualized. Diagnosis of leiomyoma of the urinary bladder / ureter would be confirmed upon histopathology and immunohistochemistry study features of trans urethral resection biopsies of the lesion which would tend to show smooth muscle spindled-cells with no evidence of atypia, or necrosis, or haemorrhage and associated with a low Ki67 index. Trans-urethral resection of the urinary bladder lesion tends to be undertaken for small to medium sized lesions with good outcome but this tends to be associated with about 18% recurrence rate that would require further resections or surgical excision to ensure complete removal of the lesion and no further recurrences. Surgical excision of the lesion including partial cystectomy, local excision / enucleation have been very effective for the treatment of larger leiomyomas with no reported recurrence so far; nevertheless, patients who undergo augmentation cystoplasty or total cystectomy and urinary diversion would need to cope with the functional problems related to the cystoplasty or urinary diversion. Differential diagnoses of leiomyoma of the urinary bladder / ureter include leiomyosarcoma, urothelial carcinoma and other malignant lesions affecting the urinary bladder. There is need for clinicians to explore minimal invasive surgery to treat patients who have leiomyoma of the bladder / ureter especially those who have multiple co-morbidities and the alterative management options that could be undertaken in multi-centre trials include: Cryotherapy, radiofrequency ablation, irreversible electroporation, high frequency ultrasound treatment and super-selective embolization of the arterial branch supplying the leiomyoma. Patients who develop ureteric obstructions would additionally require nephrostomy insertions or insertion of ureteric stents as a temporary measure to improve their renal functions.