[Primary ureteral leiomyosarcoma: a rare cause of obstructive uropathy].

Objectives: Transitional cell carcinoma is the most frequent primary malignant neoplasia obstructive ureteral pathology. Nevertheless, obstructive primary ureteral leiomyosarcoma (stromal tumour) is an unusual disease, diagnosed by histopathological examination of nephroureterectomy surgical specimens.

Methods/results: We report a case of ureteral obstructive uropathy in a 38-year-old woman, with non functional left kidney. Intravenous and retrograde pyelography revealed pyelocalyceal and ureteral dilatation and a large polypoid intraluminal lobulated mass in the pelvic ureter. Pathologic and immunohistochemical techniques showed a nonepithelial, stromal malignant tumour with appearance of smooth muscle cell differentiation: leiomyosarcoma.

Conclusions: Primary leiomyosarcoma is an unusual ureteral obstructive etiology and should be considered in this condition. Correct preoperative diagnosis is rarely made and this tumour is diagnosed by pathological examination. Abdomino-pelvic computerized tomography scan and ultrasound should be performed before diagnosing a lesion with these features as a primitive ureteral tumour.