Uncommon muscle metastatic sites of renal cell carcinoma

Abstract

Introduction. Renal cell carcinoma (RCC) is the most common malignant renal tumor. It has a tendency for spreading to unusual and distant sites, such as the orbit, paranasal sinuses, thyroid gland, heart, skin, and muscles. Skeletal muscle metastases are accounting for only 0.4% of all metastatic localizations. Following CT, they may be presented in five different radiology types of lesions. The aim of our case was CT evaluation of rare skeletal muscle metastatic localizations of RCC, following the time interval of their occurrence in relation to the appearance of the primary tumor, with emphasis on metastases in the levator ani muscle, since this metastatic localization of RCC has not been recorded in the previous literature. Case outline. We present a 66-year-old man after partial nephrectomy, due to a primary diagnosis of RCC. Three years after the initial diagnosis, multiple distant metastases were verified at typical localizations, as well as rare localizations such as muscles, including levator ani. Conclusion. Advanced metastases in uncommon locations are most often accompanied by a poor prognosis, therefore the further algorithm includes monitoring the whole clinical and radiological status. Metastases in the levator ani muscle have been recorded for the first time in this report. Taking into account that this muscle has very important functions, such as supporting and raising the pelvic visceral structures, as well as having control of the flow of urine and defecation, it is of great importance to include this localization in the CT evaluation.