Urine analysis remains a fundamental tool for diagnosing renal and urothelial diseases. Although urinary sediment microscopy is primarily used to detect haematuria, leukocyturia, and other formed elements, it may occasionally reveal exfoliated malignant cells that prompt further diagnostic investigation. The detection of Upper Tract Urothelial Carcinoma (UTUC) through routine urinary sediment examination is uncommon, as voided urine samples typically show limited sensitivity for tumours arising in the upper urinary tract. We report the case of a 42-year-old woman who initially presented with persistent dysuria and abdominal discomfort and was treated empirically for a suspected urinary tract infection. Despite antibiotic therapy, symptoms persisted and urine culture remained negative. Subsequent urinalysis revealed proteinuria, haematuria, and leukocyturia. Microscopic examination of the urinary sediment demonstrated atypical cells characterized by nuclear membrane irregularity, coarse chromatin, prominent nucleolus, and an unusual cytoplasmic protrusion. These cytomorphological findings prompted further investigation with urine cytology, which was positive for malignant cells. Cystoscopy showed no abnormalities, leading to additional evaluation with computed tomography urography. Imaging revealed a large intraluminal mass occupying the left renal pelvis with associated hydronephrosis and para-aortic lymphadenopathy. Ureteroscopy with selective cytology and subsequent multidisciplinary assessment confirmed the diagnosis of high-grade UTUC. This case highlights the diagnostic value of meticulous urinary sediment examination. Although routine sediment analysis is not a substitute for cytology or imaging, careful morphological assessment may provide an early clue to underlying malignancy and trigger appropriate diagnostic pathways, particularly in patients with persistent urinary symptoms and negative urine cultures.
Clinica chimica acta; international journal of clinical chemistry. 2026 Apr 26 [Epub ahead of print]
Oscar D Pons-Belda, Cristina Prado-Majan, Paula López-Agulló, Ana Calbet-Tur, Emilia Moreno-Noguero
Department of Clinical Analysis, Hospital Can Misses, Eivissa, Spain. Electronic address: ., Primary Care, Ibiza and Formentera Health Area, Illes Balears, Spain., Department of Pathology, Hospital Can Misses, Eivissa, Spain., Department of Clinical Analysis, Hospital Can Misses, Eivissa, Spain.