Coinciding Bladder Leiomyoma and Renal Angiomylipoma: A Case Report.

Benign mesenchymal neoplasms are rare tumors of the bladder and kidney. The most common mesenchymal bladder tumor is the leiomyoma, while angiomyolipoma is the most frequent mesenchymal renal tumor. Despite being the most frequent of benign bladder mesenchymal neoplasms at 35%, leiomyomas comprise just 0.43% of all bladder tumors.¹ Angiomyolipomas are similarly rare, identified in less than 0.2% of the general population.³

It’s hypothesized that both are influenced by estrogen. Given the low frequency that these tumors are encountered, they pose a unique challenge to clinicians and guidelines for diagnosis and treatment remain unclear. 

Methods or Case Description: We present the case of a 64-year-old female patient with simultaneous leiomyoma of the bladder and renal angiomyolipoma, along with history of uterine leiomyomas. Pathology was confirmed via transurethral resection of the bladder tumor and percutaneous biopsy of the renal mass. Pathology of bladder lesion revealed this mass to be positive for desmin and SMA, and negative for S100, CD34, and C KIT, consistent with pathological diagnosis of leiomyoma.  Pathology of the renal mass demonstrated cells positive for Melan- A and HMB - 45, as well as Caldesmon and smooth muscle actin, consistent with renal angiomyolipoma. 

Outcomes: The patient was presented with possible treatment modalities and a joint decision was made to pursue active surveillance with annual imaging.

Conclusion: Leiomyomas of the urinary bladder and angiomyolipomas of the kidney are infrequently encountered neoplasms and even more rare to occur simultaneously.  Their rarity makes them a challenge to current clinicians as their are no guidelines for treatment or diagnosis. Additional research into the etiology, development and typical course should be pursued as well as investigating a possible relationship between bladder and uterine leiomyomas with renal angiomyolipomas is required.