Though the primary diagnostic utility of urine cytology is in the detection of high grade urothelial carcinoma, malignancies other than those of urinary tract origin may also be present. Direct invasion of the bladder by an adjacent neoplasm, metastasis from a distant primary, or inadvertent contamination during specimen collection may all result in nonurothelial tumor cells being present in a urine cytology specimen. Here, we report a case of endometrial adenocarcinoma that was first identified in a voided urine specimen collected for the routine evaluation of hematuria. The presence of cohesive clusters with apparent glandular differentiation raised the possibility of a nonurothelial neoplasm and prompted an additional workup. Immunohistochemical stains performed on cell block material demonstrated that the glandular cells were positive for PAX8 and negative for GATA3, suggestive of gynecologic origin. A subsequent endometrial curettage and hysterectomy revealed endometrial adenocarcinoma. When faced with papillary groups in a voided urine specimen, the cytopathologist must remember to consider a broad differential diagnosis to include malignancies outside of the urinary tract. It was our awareness of valuable clinical information and keen cytologic assessment which allowed for an accurate diagnosis in the setting of this unexpected finding.
Keywords: atypical glandular cells; endometrial carcinoma/adenocarcinoma; urine.
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