The authors present two cases of primary @entity1492 ( @entity1492 ) of the kidney. Both @entity1 had a mass in the upper part of the left kidney without any primary @entity1313 . Grossly, the @entity5 were solid masses both measuring 7.5  cm in the greatest diameter. Histologically, one of the lesions exhibited a predominantly lobular growth of round or oval small uniform epithelioid cells in variable cellularity. Circular zones of crowded @entity5 cells alternating with hypocellular collagenous tissue in a concentric fashion around entrapped native renal tubules were distinctive. The second case was distinctive with significant cytological atypia in the neoplastic cells and prominent reactive proliferations in the trapped renal tubules. Immunohistochemically, @entity2277 , @entity588 and @entity5088 were diffusely positive in both. They were negative for @entity2281 protein, @entity2280 , and desmin, whereas @entity3778 were positive in one lesion. Fluorescence in situ hybridization assay using dual staining probes detected @entity12726 - @entity12522 fusion in each lesion, which is characteristic molecular findings of @entity1492 . One @entity1 presented widespread distant metastases at the time of diagnosis. In the other, no @entity5 deposits were detected other than primary. Both @entity1 have been alive with 30 and 10  month follow-ups, respectively. These @entity5 are 6th and 7th cases of primary renal @entity1492 in the literature confirmed by FISH study, which exhibit unique and remarkable histomorphologic features.

Primary XXXX of kidney with variant histomorphologic features: report of 2 cases and review of the literature.

@entity1 :: ('9606', 'Species') :: ['patients', 'patient'] @entity588 :: ('596', 'Gene') :: ['bcl-2'] @entity1313 :: ('MESH:D001932', 'Disease') :: ['extrarenal neoplastic lesions'] @entity5 :: ('MESH:D009369', 'Disease') :: ['tumor', 'tumors'] @entity3778 :: ('4267', 'Gene') :: ['CD99'] @entity12522 :: ('90993', 'Gene') :: ['CREB3L1'] @entity1492 :: ('MESH:D005354', 'Disease') :: ['SEF', 'sclerosing epithelioid fibrosarcoma'] @entity2277 :: ('7431', 'Gene') :: ['vimentin'] @entity2280 :: ('947', 'Gene') :: ['CD34'] @entity12726 :: ('2130', 'Gene') :: ['EWSR1'] @entity5088 :: ('4585', 'Gene') :: ['MUC4'] @entity2281 :: ('6271', 'Gene') :: ['S-100']
@entity1492 :: (MESH:D005354,Disease) :: ['sclerosing epithelioid fibrosarcoma']
