Upper Tract Urothelial Carcinoma Complicated by Skeletal Muscle Metastases.

Urothelial carcinoma typically metastasizes via a lymphatic route to sites such as lymph nodes, bone, and liver. As in other malignancies, metastasis to skeletal muscle is rare. We present a case of a 66-year-old male with severe muscular pain after diagnosis of upper tract urothelial carcinoma, who was found to have extensive metastasis to skeletal muscles including gluteal, sternocleidomastoid, deltoid, vastus lateralis, and gastrocnemius muscles. Literature review demonstrated 18 previously reported cases of urothelial cell carcinoma with skeletal muscle metastasis, all male and all with bladder involvement. This case emphasizes the importance of thoroughly evaluating all muscular pain in patients with a history of malignancy as it may represent skeletal muscle metastasis with an associated increase in morbidity and mortality.