Urothelial carcinoma with oncocytic features: an extremely rare case presenting a diagnostic challenge in urine cytology.
Recognizing histological variants in urothelial carcinoma (UC) is important because some may be associated with different clinical outcomes and/or therapeutic approaches; being aware of unusual histological variants may also be crucial in preventing diagnostic misinterpretations. Histological variants based on cytoplasmic features, such as clear-cell, plasmacytoid, rhabdoid, and lipoid-rich variants, are described in invasive UC; however, these cytoplasmic features are not formally defined and not usually encountered in non-invasive UC. Oncocytic cytoplasm has not been well described in either invasive or non-invasive UC. Herein, we report an exceedingly rare case of UC with oncocytic features arising in the right renal pelvis, which presented a diagnostic challenge in urine cytology due to the relatively low nuclear-to-cytoplasmic ratio; however, it could definitively be diagnosed using histological specimens. UC diagnosis is based on the presence of papillary architecture and widespread p53 nuclear accumulation, suggesting malignancy. An oncocytic tumor is generally considered to be not actively dividing, as shown by the low Ki-67 labeling index in this case. In spite of the low proliferative activity, the possibility of intravesicle recurrence (IVR) should be considered since positive preoperative cytology of upper tract UC is a risk factor for IVR after nephroureterectomy.
Department of Pathology, Graduate School of Medicine, The University of Tokyo Tokyo, Japan ; Department of Pathology, Fujieda Municipal General Hospital Shizuoka, Japan.
Shogo
S
Tajima
D000368:Aged; D014408:Biomarkers, Tumor / Q000032:analysis; D002277:Carcinoma / Q000737:chemistry / Q000473:pathology* / Q000601:surgery / Q000652:urine*; D006801:Humans; D007150:Immunohistochemistry; D007680:Kidney Neoplasms / Q000737:chemistry / Q000473:pathology* / Q000601:surgery / Q000652:urine*; D007682:Kidney Pelvis / Q000737:chemistry / Q000473:pathology* / Q000601:surgery; D008297:Male; D008854:Microscopy, Electron; D009392:Nephrectomy; D024862:Oxyphil Cells / Q000737:chemistry / Q000473:pathology*; D011237:Predictive Value of Tests; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D016159:Tumor Suppressor Protein p53 / Q000032:analysis; D016482:Urinalysis; D014556:Urine / Q000166:cytology*; D019459:Urothelium / Q000737:chemistry / Q000473:pathology* / Q000601:surgery
D014408:Biomarkers, Tumor; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53
Urothelial carcinoma; histology; immunohistochemistry; oncocytic features; renal pelvis; urine cytology