Esophageal squamous cell carcinoma recurring as a solitary renal mass

Herein, a case of solitary, unilateral renal metastasis in a patient with curatively resected thoracic esophageal carcinoma, who achieved a pathological complete remission after neoadjuvant concurrent chemoradiotherapy, is reported. The kidney is the 4(th) or 5(th) most common visceral metastasis site of a primary esophageal carcinoma. More than 50% of renal metastases typically show bilateral involvement. Solitary, unilateral renal metastasis is extremely rare. Renal metastases from a primary esophageal carcinoma are usually latent and its diagnosis is very unusual in a live patient. The solitary renal metastasis in this case was not accompanied by metastases to other sites. The value of a nephrectomy in solitary renal metastasis of esophageal cancer is not known due to the rarity of such cases. A nephrectomy could be justified in limited situations, such as with uncertainty of histological diagnosis, severe life-threatening hematuria, which cannot be controlled by embolization, or solitary renal metastasis with a long disease-free interval.