Angiomyxoma of the Ureter Imitating an Upper Tract Urothelial Carcinoma: A case report - Beyond the Abstract

Angiomyxoma is a mesenchymal neoplasm most commonly reported in women with a 6:1 female to male ratio. Angiomyxoma is most commonly reported involving the pelvis. In female patients, the tumor was found in the vagina, vulva, uterine cavity and urinary bladder. In male patients, it was found involving the scrotum, spermatic cord, prostate, penis, and urethra. Angiomyxoma is described as a slowly growing displacing mass rather than invading adjacent structures with no distant metastasis. 

Aggressive behavior is often due to its infiltrative nature with frequent association with local recurrence attributed to inadequate surgical resection when not anticipated preoperatively.

Angiomyxoma do not commonly present with pathognomonic features on imagining, particularly if presented in atypical locations. Cross-sectional imaging, CT (computerized tomography) or MRI (Magnetic Resonance Imaging), may provide the best imagining information for preoperative diagnostic planning to-date. These tumors tend to be large, displacing masses with an unusual growth pattern. Pathologically angiomyxoma contain stroma with loose myxoid and high-water content background. This contributes to the high signal intensity on T2 weighted images on MRI, which may serve as a diagnostic clue. Additionally, the fibrovascular tissue may present as heterogeneous “swirled” enhancing bands.

From a radiological perspective, the atypical and uncommon presentation of angiomyxoma in the ureter would have been difficult to suggest based on CT features alone. This is related to the overlapping features of the presenting mass, in comparison to the more common tumors such as TCC (Transitional cell carcinoma) and fibroepithelial polyps. MR (Magnetic Resonance) urography may have suggested some of the above-described clues which may have helped in suggesting an alternative tumor type particularly with a myxoid matrix that is not typical to the more common urothelial neoplasms. Cross-sectional imaging will have served best in outlining the tumor origin, extent and signal characteristics.

Surgery with complete excision remains the first-line treatment for aggressive angiomyxoma eradication according to available evidence. We believed that a ureteral biopsy could have led to an organ-sparing surgery if angiomyxoma were to be considered in our differential diagnosis.

Urology Guidelines recommend doing a CT urography and a diagnostic ureteroscopy before treatment but the guidelines also state that the use of diagnostic ureteroscopy and biopsy are to be done in cases where additional information will impact treatment decisions. In our case, there was no doubt about the decision of treatment after seeing the images. As this is the first case documented in the ureter it would be very difficult to think of anything else than a malignant tumor.

Written by: Jamil AK Addas, MD1 and Ahmed S. Zugail, MD2 
1. Senior Radiology Resident, the University of Toronto, Ontario, Canada
2. Senior Urology Resident, Sorbonne University, Paris, France

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