[390] Renal Cell Carcinoma with Rhabdoid Features: Cytologic Features on Fine Needle Aspiration Biopsy

Li Yan Khor, Christopher G Przybycin, Stephen Gmitro, Cristina Magi-Galluzzi, Jordan P Reynolds. Cleveland Clinic, Cleveland, OH

Background: Rhabdoid differentiation (RD) in renal cell carcinoma (RCC) is associated with poor prognosis. Distinction of RD from oncocytic renal neoplasms is challenging due to overlapping cytologic features. Fine needle aspiration (FNA) cytology of RCC with RD is not well-described. Our aim was to establish consistent cytologic features to detect RD in FNA biopsies.
Design: We performed a search for cases of primary or metastatic RCC with RD with concurrent FNA. Cases were reviewed for RD and compared to consecutive FNA of oncocytic kidney neoplasms with histologic follow up. Cytologic parameters were defined (Table 1), and cases were screened by a cytotechnologist and a fellow. Fisher exact test was performed to determine if each parameter of RD was significantly different when compared to conventional oncocytic neoplasms.
Results: 76 specimens contained RCC with RD: 68 clear cell RCC (CCRCC), 1 papillary RCC, 1 chromophobe RCC (ChRCC) and 6 unclassified RCC. 6 of these had FNA; 2 cases were from primary kidney tumors and 4 from metastases (2 lung, 1 liver, 1 distant lymph node). RCC with RD were compared to 17 conventional (non-RD) oncocytic tumors (6 CCRCC, 3ChRCC, 4 oncocytomas, and 4 benign kidneys with fibrosis). 6 parameters on FNA were significantly associated with RCC with RD (p<.01): irregular nuclear membrane, vesicular nuclei, eccentric nuclei, vesicular cytoplasm, intracytoplasmic inclusions and ill-defined cell borders (Table 1).
Conclusions: In this series, we describe key cytologic features of RCC with RD, which were even identified in metastases. As RD is associated with poor prognosis, the presence of characteristic parameters on initial FNA may signify a more aggressive neoplasm suggesting early definitive management.

Cytologic parameters in RCC with rhabdoid features
 Non rhabdoid (n=17)Rhabdoid (n=6) 
Follow up histology (n=23)Parameter absentParameter presentParameter absentParameter presentp-value (Fisher exact test)
Nuclear enlargement2 (12%)15 (88%)06 (100%)0.53
Irregular nuclear membrane17 (100%)006 (100%)<.001
Vesicular nuclei15 (88%)2 (12%)06 (100%)<.001
Central nuclei2 (12%)15 (88%)6 (100%)0<.001
Eccentric nuclei15 (88%)2 (12%)06 (100%).003
Prominent nucleolus8 (47%)9 (53%)5 (83%)1 (17%).3401
Granular cytoplasm17 (100%)06 (100%)0<.001
Vesicular cytoplasm15 (88%)2 (12%)06 (100%).0003
Intracytoplasmic inclusion17 (100%)03 (50%)3 (50%).0113
Well-defined cell borders7 (41%)10 (59%)6 (100%)0.0191
Ill-defined cell borders11 (65%)6 (35%)06 (100%).0137
Cohesive sheets6 (35%)11 (65%)6 (100%)0.0137
Loss of cohesion3 (18%)14 (82%)06 (100%).5392

Category: Cytopathology

Monday, March 4, 2013 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 55, Monday Morning


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