Undifferentiated Pleomorphic Sarcoma
Undifferentiated pleomorphic sarcoma (UPS) is a malignant mesenchymal tumor with no identifiable line of differentiation. It is a therefore diagnosis of exclusion.
UPS originating in the genitourinary tract is rare, and literature consists mainly of single case reports.
UPS is a tumor of adults, arising mainly in patients between the fifth and the eight decades.
It occurs predominantly in males.
Genitourinary UPS arises more frequently in the urinary bladder, but few examples have also been reported in the kidney, the prostate, and the spermatic cord (Kunze et al. 1994; Kulmala et al. 1994; Ptochos et al. 1999; Demir et al. 2012).
Treatment is surgical, combined in some cases with chemotherapy and radiation.
UPS is an aggressive tumor with frequent local and distant relapse and a poor prognosis.
UPS usually appears as a large multilobulated gray-white, fleshy mass. The cut surface often shows hemorrhagic, myxoid, and/or necrotic changes.
Immunohistochemically, tumor cells are positive for vimentin and focally for smooth muscle actin. H-caldesmon, desmin, S100 protein, and epithelial markers are usually not expressed.
UPS presents complex genomic aberrations.
UPS can be diagnosed after having excluded other high-grade spindle and pleomorphic malignancies. The main differential diagnosis in the urogenital tract is with sarcomatoid carcinoma (de Peralta-Venturina et al. 2001), which presents morphologic and immunohistochemical overlaps with UPS (positivity for vimentin and focal expression of actin). However, sarcomatoid carcinoma presents an epithelial component, or, even in absence, it is at least focally immunoreactive to cytokeratin and/or EMA. Other high-grade pleomorphic sarcomas can be excluded by searching for specific lines of differentiation, also with the help of an appropriate immunohistochemical panel.
References and Further Reading
- de Peralta-Venturina, M., Moch, H., Amin, M., Tamboli, P., Hailemariam, S., Mihatsch, M., Javidan, J., Stricker, H., Ro, J. Y., & Amin, M. B. (2001). Sarcomatoid differentiation in renal cell carcinoma: A study of 101 cases. The American Journal of Surgical Pathology, 25, 275–284.CrossRefGoogle Scholar
- Demir, L., Can, A., Dirican, A., Bayoğlu, V., Rezanko, T. A., Akyol, M., Kucukzeybek, Y., Erten, C., & Tarhan, M. O. (2012). Malignant fibrous histiocytoma of the spermatic cord in a patient with polycystic kidney disease; review of the literature. Clinical Genitourinary Cancer, 10, 280–283.CrossRefGoogle Scholar