Abstract
Background: Renal medullary carcinoma (RMC) is a diagnostically challenging, aggressive primary renal malignancy associated with abysmal survival. Delays in diagnosis contribute to most patients having diffusely metastatic disease at the time of initial presentation. Methods: We present the case of a 13-year-old African American male with sickle cell trait who presented with a renal mass and hematuria. Evaluation included imaging, fluid cultures, and cytologic assessment. Results: Patient was diagnosed with RMC based on cytologic assessment of sub-centimeter fluid collections aspirated from the left kidney at the time of cortical biopsy for suspected renal mass. The additional fluid aspiration in conjunction with renal biopsy was an atypical but crucial step in early diagnosis. Conclusion: Cytomorphologic evaluation of fluid biospecimens is not currently part of the standard work-up for patients with renal masses but, when available, can provide crucial information that reduces time to diagnosis. Prompt symptom recognition and treatment initiation may improve patient outcomes. © 2023 The Authors. Journal of Clinical Laboratory Analysis published by Wiley Periodicals LLC.