Gross Hematuria Revealing Bilateral Renal Metastases From Pulmonary Squamous Cell Carcinoma: A Case Report.

Renal metastases from lung cancer are uncommon in clinical practice and are usually asymptomatic. Bilateral renal metastases presenting with gross hematuria as the initial manifestation of pulmonary squamous cell carcinoma (SCC) are exceptionally rare. We describe the case of a 67-year-old man with a 50-year smoking history who presented with painless hematuria, bilateral flank pain, intermittent fever, and weight loss. Abdominal computed tomography (CT) revealed bilaterally enlarged kidneys containing multiple hypodense lesions, while chest CT revealed a right hilar mass with collapse of the right middle and lower lobes. CT-guided biopsies of both the renal and pulmonary lesions confirmed a poorly to moderately differentiated SCC. Immunohistochemistry showed positivity for p63, CK5/6, and CK7 and negativity for CK20 and uroplakin, confirming bilateral renal metastases from a primary pulmonary SCC. Following multidisciplinary discussion, systemic therapy was initiated, as surgical management was not indicated. This case highlights the importance of including metastatic lung cancer in the differential diagnosis of bilateral renal masses presenting with hematuria and underscores the pivotal role of renal biopsy in establishing the correct diagnosis.