Splenosis Unmasked: Incidentally Rediscovered in a Patient With Nephrolithiasis and Remote Splenectomy

Splenosis is the autotransplantation of splenic tissue that can occur after splenic rupture or splenectomy. It is usually asymptomatic and discovered incidentally. Nephrolithiasis is a common cause of acute flank pain, often diagnosed by non-contrast computed tomography imaging. Splenectomy has been reported as a risk factor for nephrolithiasis in selected hematologic conditions, although its relevance in patients without hematologic disease remains uncertain. A 65-year-old man presented with acute left flank pain. Results of computed tomography imaging of the abdomen confirmed left-sided nephrolithiasis and also revealed multiple well-circumscribed soft tissue nodules in the lower abdomen and pelvis, raising concern for metastatic disease. A detailed history revealed previous splenectomy following an automobile accident at the age of 6 and confirmed splenosis years earlier by technetium scan prior to this admission. The patient's past medical history of splenectomy and proper history supported the diagnosis of splenosis. This case report highlights the importance of recognizing splenosis as a benign mimic of malignancy on imaging. Thorough history-taking and awareness can prevent unnecessary diagnostic testing and interventions. A history of splenectomy can be a risk factor for nephrolithiasis in individuals with certain hematological diseases.