Genitourinary And Sarcomas
Although STSs of the genitourinary tract are uncommon in adults, they account for up to 8% of all malignant disease in children younger than 15 years.503 The management of genitourinary sarcomas in children has been more successful than that in adults and is discussed in detail elsewhere in this book. In the Memorial Sloan Kettering Cancer Center adult sarcoma database, only approximately 3% were of genitourinary origin. The paratesticular region (33%) and prostate or seminal vesicles (28%) are the most frequent sites of genitourinary sarcomas, followed by the bladder (23%) and kidneys (16%). The most common histologic subtypes in adults are leiomyosarcoma (44%) and rhabdomyosarcoma (33%), although a spectrum of other histologic subtypes has been reported.504
A feature of genitourinary sarcomas that distinguishes them from other sarcomas is the fact that the vast majority of these lesions are of high histologic grade. In a report from the Memorial Sloan Kettering Cancer Center, fully 86% of genitourinary sarcomas were high grade, and 56% were larger than 5 cm.504 Similar findings have been reported from the MD Anderson Cancer Center, where 15 (88%) of 17 primary sarcomas of the kidney met pathologic criteria for high-grade classification and tumor size ranged from 5.5 to 23 cm.505 These findings have obvious prognostic implications, and series reports have indicated relatively poor 5-year OS rates for patients with high-grade histologic type (48% versus 100% for low-grade lesions) or large tumor size (30% for lesions ≥5 cm versus 83% for lesions <5 cm).
Signs and Symptoms:
Leiomyosarcoma has rather vague symptoms, allowing it to mature gradually. If the tumor is cutaneous, it manifests as small, solitary nodules. If the tumor is deep, it tends to arise near medium to large veins. Rarely, leiomyosarcoma can be found near large vascularized structures. In these cases, the tumor obstructs the vessel leading to decreased outflow. This occurs most frequently in the pulmonary artery.
Diagnosis is based on the presence of smooth muscle actin and desmin by immunochemistry. Imaging from computed tomography scans and magnetic resonance imaging scans can be very useful when contrast materials are used.
Typically elongated cells with abundant cytoplasm can be seen. Multinucleated giant cells can occur as well. It is also possible for epithelioid changes to occur, such as a cell becoming rounded with concomitant clear cell changes in the neoplasm.
Leiomyosarcoma is most often discovered by chance; however, abdominal cramping, bloating, or vaginal bleeding is possible due to the growth of the tumor.
The keystone treatment is complete resection. Chemotherapy has not been shown to be beneficial in some cases.