Gastrocnemius acrometastasis from muscle-invasive urothelial bladder carcinoma: A case report

Urinary bladder carcinoma is a common malignancy worldwide. The metastatic disease to distant organs including lung, liver, and bone is well established. However, metastasis to below-knee-level; also known as acrometastasis is a rare occurrence and occurs approximately 0.1% of all bone metastases. It is standard of care to obtain a contrast enhanced computed tomography scan of the chest, abdomen, and pelvis for pretreatment planning, primary staging, and post treatment disease surveillance. This makes the occurrence of acrometastasis harder to detect and may only manifest clinically in advance disease. We report a case of 55 years old gentleman treated as muscle-invasive bladder urothelial carcinoma, presented with chronic left knee pain, and imaging demonstrating tumor in the left knee region. Histopathologic study shows features of metastatic disease from urinary bladder carcinoma to the left gastrocnemius muscle. The attending physician should raise the suspicion of metastatic disease if the patient with known malignancy presented with new soft tissue lesion elsewhere in the body.