S3080 Metastatic Renal Cell Carcinoma as a Cause of Solitary Gastric Polyp

Abstract

Introduction: Renal Cell Carcinoma (RCC) is the most common cancer originating from the kidney, accounting for 80-85% of all primary renal neoplasms. Clear cell carcinoma represents the most common histopathological subtype. About 30% percent of RCC cases have metastasized at the time of initial presentation. The classical sites of metastasis include the lungs, bones, liver, and brain. RCC metastasis to the stomach is extremely rare, occurring in approximately 0.2% of RCC cases. We present a rare case of solitary gastric polyp due to metastatic RCC. Case Description/Methods: A 64-year-old female with a past medical history of hypertension and gastroesophageal reflux disease presented to the clinic with a 4-month history of post-prandial intermittent right-sided abdominal pain denied hematuria or melena. Vital signs were normal. On examination, she had right-sided fullness. Labs were significant for hemoglobin of 9 g/dL. Abdominal ultrasound revealed a 13-cm mass in the right upper quadrant arising from the pole of the right kidney. This was confirmed by MRI which showed significant parasitic vessels in and around the mass. The patient underwent esophagogastroduodenoscopy for evaluation of anemia that showed a solitary 5-mm sessile polyp in the gastric body with no evidence of active bleeding. The pathology of the polyp removed indicated clear cell carcinoma, consistent with metastatic RCC. Chest CT showed subcarinal lymphadenopathy with a conglomerate measuring 5.3 cm x 3.1 cm, evidence of multiple 4-7 mm lung nodules – two on the right and one on the left. The patient was referred to the medical oncologist and systemic immunotherapy was commenced. Discussion: This report highlights the rarity of stomach metastasis in RCC, which likely occurred by hematogenous spread due to an abundant renal blood supply. Other routes of metastasis include lymphangitic spread and contiguous spread via the renal capsule, renal pelvis, and ureter (3). The Stomach metastasis can present as solitary/multiple polyps or an ulcer. Lesions are usually asymptomatic and occur in the gastric fundus or body. When symptomatic, gastrointestinal bleeding and anemia are the most common presentation. Patients with RCC and gastric metastasis usually have metastatic lesions in other organ systems, as seen in our patient, and the prognosis for such patients is poor. Therefore, this rare entity should be considered in a patient with gastrointestinal symptoms in the setting of underlying Renal cell carcinoma.