Urine cytology in the detection of renal cell carcinomas - a territory-wide multi-institutional retrospective review of more than 2 decades.

INTRODUCTION: Compared with urothelial lesions of the upper urinary tract, the diagnostic performance of urine cytology in detection of renal cell carcinomas is underreported. This study aims to establish the role of urine cytology in the assessment of renal carcinomas by a multi-institute review of urine cytology from nephrectomy confirmed renal cell carcinomas, referenced against renal urothelial and squamous cell carcinomas. METHODS: Records of nephrectomy performed from the 1990s to 2020s at three hospitals were retrieved and matched to urine cytology specimens collected within 1 year prior. Patient demographics, specimen descriptors, and histology and staging parameters were reviewed and compared against cytologic diagnoses. RESULTS: There were 1147 cases of urine cytology matched with renal cell carcinomas, with 666 renal urothelial/squamous carcinomas for comparison. The detection rate for urothelial/squamous (atypia or above [C3+]: 63.1%; suspicious or above [C4+]: 24.0%) were higher than renal cell carcinoma (C3+: 13.1%; C4+: 1.5%) (p < 0.001). The positive rate for upper tract urine exceeded other collection methods at 45.0% (C3+) and 10.0% (C4+) (p < .01). Other factors associated with increased positive rates were male sex, collecting duct carcinoma histology, nuclear grade, and renal/sinus involvement (p < .05). Multivariate analysis revealed additional positive correlations with presence of sarcomatoid tumor cells, lymphovascular invasion, and perinephric fat involvement (p < .05). Larger lesion size and higher urine volume did not improve detection rates (p < .05). CONCLUSIONS: The detection rate of renal cell carcinomas is suboptimal compared with urothelial carcinomas, although urine samples collected from cystoscopy or percutaneous nephrostomy significantly outperformed voided urine specimens.

Prevalence and interpretation of AFF immunostain of DEK::AFF2 fusion-associated papillary squamous cell carcinoma in a retrospective cohort of recurrent sinonasal papillomas.

DEK::AFF2 fusion-associated papillary squamous cell carcinoma is a novel entity characterized by its unique translocation and malignant clinical course. In this study, AFF immunohistochemistry (IHC) was performed in recurrent sinonasal papillomas for reviewing the prevalence of undiagnosed DEK::AFF2 carcinomas and to investigate the performance of AFF IHC in diagnosis of DEK::AFF2 carcinomas. Recurrent sinonasal papillomas after surgical excision in a two-decade period were retrieved. Histologic slides were reviewed for features of DEK::AFF2 carcinoma. AFF IHC was performed, and cases with any (> 1%) nuclear positivity were validated by DEK break apart fluorescence in situ hybridization. Totally 43 cases were included, comprising 28 inverted, 6 exophytic, one oncocytic, and 8 non-specified sinonasal papillomas. Five (11.6%) cases exhibited positivity to AFF IHC. Three cases exhibited patchy weak to moderate staining intensity predominantly in a granular cytoplasmic pattern. Two cases exhibited strong and diffuse (> 90%) nuclear staining. Cases showing weak staining were negative for DEK rearrangement, while those with strong staining were positive. Both cases of DEK::AFF2 carcinoma showed aggressive behavior with extensive local invasion and nodal metastasis. Background stromal plasma cells, when present, consistently showed strong and diffuse staining. AFF IHC was further performed in plasmacytoma samples as control and showed strong and diffuse immunoreactivity. A significant minority of recurrent sinonasal papillomas represent DEK::AFF2 carcinomas. Granular, cytoplasmic, or incomplete AFF staining should be considered as negative. In view of the rarity of DEK::AFF2 carcinomas, plasma cells and plasma cell neoplasms are potential for internal and surrogate external controls.