Recurrent KRAS mutations are early events in the development of papillary renal neoplasm with reverse polarity

none22siWe evaluated the clinicopathologic and molecular characteristics of mostly incidentally detected, small, papillary renal neoplasms with reverse polarity (PRNRP). The cohort comprised 50 PRNRP from 46 patients, divided into 2 groups. The clinically undetected ( T (n = 21), c.34 G > T (n = 3), c.35 G > A (n = 2), c.34 G > C (n = 2) resulting in p.Gly12Val, p. Gly12Asp, p.Gly12Cys and p.Gly12Arg, respectively. One PRNRP had a G12A/V/D complex mutation. Twenty-six PRNRP were concurrently present with other tumors of different histologic subtypes in the ipsilateral kidney; molecular testing of 8 of the latter showed wild-type KRAS gene despite the presence of KRAS mutations in 5 concurrent PRNRP. On follow up, no adverse pathologic events were seen (range 1–160 months; mean 44 months). In conclusion, the presence of KRAS mutations in small, clinically undetected PRNRP provides a unique finding to this entity and supports its being an early event in the development of these neoplasms.noneAl-Obaidy K.I.; Saleeb R.M.; Trpkov K.; Williamson S.R.; Sangoi A.R.; Nassiri M.; Hes O.; Montironi R.; Cimadamore A.; Acosta A.M.; Alruwaii Z.I.; Alkashash A.; Hassan O.; Gupta N.; Osunkoya A.O.; Sen J.D.; Baldrige L.A.; Sakr W.A.; Idrees M.T.; Eble J.N.; Grignon D.J.; Cheng L.Al-Obaidy, K. I.; Saleeb, R. M.; Trpkov, K.; Williamson, S. R.; Sangoi, A. R.; Nassiri, M.; Hes, O.; Montironi, R.; Cimadamore, A.; Acosta, A. M.; Alruwaii, Z. I.; Alkashash, A.; Hassan, O.; Gupta, N.; Osunkoya, A. O.; Sen, J. D.; Baldrige, L. A.; Sakr, W. A.; Idrees, M. T.; Eble, J. N.; Grignon, D. J.; Cheng, L