primary malignant tumors of renal pelvis are relatively rare and constitute about 8 - 14% of all renal malignancies ( 1 ) . urothelial carcinoma occurs in more than 90% of cases and scc only in 0.7% to 7% ( 2).these tumors are mostly seen in adults and less commonly in pediatric age groups . although the pelvic tumors are detected clinically at an early stage because of early desquamation of cells and hematuria , still the survival rate is not good enough . the common etiological factors include renal calculi , infections , endogenous and exogenous chemicals , vitamin a deficiency and hormonal imbalance , however , scc have been reported even in the absence of these factors ( 3 ) . the case being reported had scc of renal pelvis presenting as hydronephrosis and chronic pyelonephritis in the absence of renal calculi and other predisposing factors . a 52 years old male patient , farmer by occupation presented with complaints of heaviness and swelling in left side of upper abdomen since one year . the swelling was increasing in size gradually with occasional episodes of pain in left loin without radiation to any other side and occasional burning sensation during micturition . ultrasonography of abdomen showed grade - iii hydronephrosis in left kidney with dilated pelvis and ureter . there was no free fluid and the right kidney was normal in size , shape and echotexture . intravenous pyelography ( ivp ) showed prompt secretion of contrast by right kidney , which measured 14.45.9 cm with normal pelvicalyceal system . diethylene triamine penta - acetic acid ( dtpa ) scan revealed non - functioning left kidney with glomerular filtration rate ( gfr ) of 0.28 ml per minute per 1.73 m with total gfr 61ml / min/1.73 m ( normal value : 64.8ml / min/1.73 m ) and right kidney was normally functioning with gfr of 60.7 ml / min/1.73 m . a large photon deficient area was noticed in left renal fossa in the initial images . no significant tracer uptake was noticed in left kidney in the entire course of study till 4hrs . the patient underwent nephrectomy for non - functioning kidney thought to be due to chronic pyelonephritis and the resected specimen was submitted for histopathology . gross examination of the specimen showed a multi - cystic sac - like structure measuring 11 x 6 x 2.5 cm along with the attached ureter . cut surface of specimen showed multiple loculi with varied appearance and thinned out wall at some places with intervening thickened areas at others ( fig 1 ) . the sections from various representative areas revealed dilated pelvicalyceal system lined by metaplastic squamous epithelium and shows changes of chronic pyelonephritis ( fig 2 ) . cyst lined by metaplastic epithelium with focus of malignant squamous cell . ( 100x h and e stain ) histopathology from solid portions in pelvis region showed features of moderately differentiated squamous cell carcinoma ( fig 3 ) . the tumor was not involving retroperitoneal soft tissue including renal vessels , gerota s fascia and lymph nodes . primary malignant tumors of renal pelvis are relatively rare , constituting 8 - 14% of all renal malignancies ( 4 ) . the most common renal malignancy in adult is clear cell carcinoma followed by papillary carcinoma and chromophobe cell carcinoma ( 5,6 ) . the kidney is unusual site for scc which is known to arise from collecting system ( 7 ) . usually renal squamous cell carcinoma is highly aggressive and of a high grade at presentation . scc of urothelial tract is thought to arise through a process of metaplasia of urothelium . various etiological factors have been held responsible for squamous metaplasia and subsequent carcinoma . of these renal calculi and infections other factors implicated include exogenous and endogenous chemical , vitamin a deficiency , hormonal imbalance , schistosomiasis and smoking . however , cases have been reported in which no apparent etiological factor could be detected ( 1,3 ) . in our case tumor squamous metaplasia in adjacent mucosa is seen in 17 - 33% of patients ( 8) . hydronephrosis or even pylonephrosis with peritoneal abscess formation have been reported in upper urinary tract carcinoma . surgery is the mainstay of treatment in scc of renal pelvis and may result in cure in patients with lower stage tumor . the prognosis of scc of renal pelvis is very poor with a median survival rate of 3.5 months . their general poor prognosis can be attributed to a typically advanced stage at diagnosis , but stage for stage prognosis is similar for squamous and usual urothelial carcinoma.(9 ) to conclude this case is reported to highlight that a diagnosis of malignancy should be considered in a long history of inflammation or infectious pathology with no known risk factors as calculi or diabetes mellitus . careful history taking may give clue for the presence of risk factors but scc of renal pelvis may occur in absence of any of predisposing condition . therefore , careful and exhaustive assessment of specimen and examination of histopathological sections is mandatory to avoid any occult malignancy in such type of non - functioning kidney .
squamous cell carcinoma ( scc ) of urinary tract is a rarely encountered tumor . 
 the incidence of this tumor is 1.4 per cent of all renal malignancies ( 1 ) . 
 we present a case of 52 years male with squamous cell carcinoma of renal pelvis , presenting as chronic pyelonephritis transforming the kidney into non - functioning multicystic cavitatory mass without any renal calculi . 
 the case highlights the rarity of tumor in absence of calculi or any other predisposing factor . 
 moreover , histology of resected specimen detected features of scc giving importance to careful and exhaustive assessment of specimen and of histologic sections , when there is no suspicion of malignancy clinically .