Indian Journal of Medical Specialities

: 2020  |  Volume : 11  |  Issue : 1  |  Page : 21--27

Prevalence of pathological lesions in 161 nephrectomies: An experience from a teaching hospital in urban industrial area of Maharashtra

Shirish S Chandanwale, Piyusha Naragude, Madhuri Singh, Akshi Raj, Sunita Bamanikar, Archana C Buch, Kushal Shah 
 Department of Pathology, Padm. Dr. D. Y. Patil Medical College, Pune, Maharashtra, India

Correspondence Address:
Dr. Shirish S Chandanwale
Department of Pathology, Padm. Dr. D. Y. Patil Medical College, Pimpri, Pune - 411 018, Maharashtra


Background: Kidneys can be involved in various pathological processes. Nephrectomy is a common procedure in urological practice. Aim: The objective of the present study is to find out the frequency of various neoplastic and non-neoplastic lesions in nephrectomy specimens and to study histomorphological features from a teaching hospital in urban industrial area. Materials and Methods: The study included 161 nephrectomy specimens. Grossly, findings were noted. Detailed histological features were studied. Lesions were broadly categorized into non-neoplastic and neoplastic. Nuclear Grading System was used to grade clear-cell renal cell carcinoma (RCC) and papillary RCC. The International Society of Pediatric Oncology staging was used to stage Wilms', tumors. The staging of RCC was done by tumor, node, and metastasis classification as per the World Health Organization 2016. Other clinical details were correlated with histomorphological features. Results: Of 161 nephrectomy specimens, 81 (50.31%) were males and 80 (49.68%) were females. The mean age was 45.43 (±19.43 standard deviation) years. 115 (71.42%) nephrectomy specimens showed -non-neoplastic lesions and 46 (28.57%) showed neoplastic lesions. The most common non-neoplastic lesions were chronic pyelonephritis in 106 (92.17%) patients. RCC (n = 36) was the most common neoplastic lesion. Conclusion: In developing countries like India, chronic pyelonephritis remains the most common cause of nephrectomy. Nephrectomy due to non-neoplastic lesions is more common in younger age group as compared to neoplastic lesions. Early diagnosis and better treatment modalities for inflammatory lesions of the kidney in the developing countries will reduce the rate of nephrectomies.

How to cite this article:
Chandanwale SS, Naragude P, Singh M, Raj A, Bamanikar S, Buch AC, Shah K. Prevalence of pathological lesions in 161 nephrectomies: An experience from a teaching hospital in urban industrial area of Maharashtra.Indian J Med Spec 2020;11:21-27

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Chandanwale SS, Naragude P, Singh M, Raj A, Bamanikar S, Buch AC, Shah K. Prevalence of pathological lesions in 161 nephrectomies: An experience from a teaching hospital in urban industrial area of Maharashtra. Indian J Med Spec [serial online] 2020 [cited 2022 Jun 30 ];11:21-27
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Renal diseases are an important cause of morbidity worldwide. 20% of all women suffer from infections of the upper or lower urinary tract at sometime in their lives.[1] The indications of nephrectomy range from inflammatory lesions causing extensive parenchymal damage to benign and malignant neoplasms.[2] It is also indicated in nontreatable renal artery disease due to reno-vascular hypertension and other conditions like nephrosclerosis and congenital dysplasia. In India, there is an increase in the number of end-stage renal diseases treated with dialysis and transplantation. Chronic pyelonephritis and its variants still continue to be the leading cause of nephrectomies despite the advent of newer and more effective antibiotics. Radical nephrectomy is standard treatment with localized renal carcinoma with a normal contralateral kidney.[3],[4],[5],[6],[7],[8],[9] In addition, there is geographical variation in the indications for nephrectomy as certain urological diseases are more prevalent in some countries. The present study is undertaken to study the frequency of various neoplastic and non-neoplastic lesions in nephrectomy specimens and to study histomorphological features.

 Materials and Methods

This study was conducted between the periods of 2014–2018 in a teaching hospital from urban industrial area. All the 161 complete or partial nephrectomy surgical specimens received for histopathological examination were included in the study. Important clinical findings including radiological findings such as ultrasonography, computed tomography (CT) scan, and magnetic imaging resonance (MRI) were noted. Renal biopsies and nephrectomy specimens received for traumatic injuries were not included in the study. The study included 161 surgically resected nephrectomy specimens. Nephrectomy specimens were examined in detail grossly. Adequate 3–4 mm sections were taken for microscopic examination as per the standard protocol. Tissues were formalin-fixed and paraffin processed. A 3–4 μm thick sections were cut and stained by hematoxylin and eosin stain. Detailed histological features were studied and lesions were broadly categorized into non-neoplastic and neoplastic. The World Health Organization (WHO)/International Society of Urological Pathology (ISUP) Nuclear Grading System was used to grade clear-cell renal cell carcinoma (RCC) and papillary RCC.[1] The International Society of Pediatric Oncology staging was used to stage Wilms', tumors.[1] The staging of RCC was done by tumor, node, and metastasis (TNM) classification as per the WHO 2016.[1] Clinical findings were correlated with histomorphological features. The acquired data was analyzed using descriptive statistics.


Out of 161 nephrectomy specimens, 81 were right kidney specimens, while 80 were left kidney. The 81 (50.31%) were males and 80 (49.68%) were females. The mean age at which nephrectomy was done was 45.43 years with male: female ratio of 1.01:1. The age of the patients ranged from 5 to 85 years with a mean age of 45.43 years (standard deviation [SD] ± 19.43). Out of 161 nephrectomies, 115 (71.42%) showed non-neoplastic lesions and 46 (28.57%) showed neoplastic lesions. Females were more commonly (n = 64) affected than males (n = 51) by nonneoplastic lesions. The most common age group involved by nonneoplastic lesions was 40–49 years (n = 28) followed by 60–69 (n = 23). They were more common in females of 40–49 years of age, while more common in males (n = 16) of 60–69 years of age. Neoplastic lesions were more common in males (n = 10) of 60–69 years of age, while more in females (n = 4) of 30–39 years of age. [Table 1] shows detailed age and sex distribution of 161 non-neoplastic and neoplastic nephrectomy lesions.{Table 1}

The important clinical features in patients were, localized flank pain 141 (87.57%), fever in 88 (54.65%), burning micturition in 64 (39.75%), an abdominal lump in 38 (23.60%) and 4 (2.48%) patients had hematuria. Nephrectomy in all patients was done based on clinical findings, ultrasonography, and CT scan and MRI. In all patients, radiological findings suggested nonfunctioning kidney or neoplastic lesions. Histomorphological features were studied in detail. The final diagnosis was made based on clinical findings including radiological findings and histomorphological features.

Out of 115 nonneoplastic lesions, 106 (92.17%) were chronic pyelonephritis, of which 84 patients had kidney stones and maximum were females (n = 49). The 22 patients developed chronic pyelonephritis without kidney stones and maximum were females (n = 13). Out of the remaining 9 cases 6 were of xanthogranulomatous pyelonephritis, 2 were of tuberculous pyelonephritis and 1 case was of autosomal dominant polycystic kidney disease (ADPKD).

The diagnosis of 28.57% (n = 46) neoplastic lesions was based on clinical and CT scan and or MRI findings. Males were commonly involved than females with male; female ratio of 1.88:1. The mean age for neoplastic lesions in males was more (49.32 SD ± 20.25) than females 41.5% (SD ± 17.71). Out of 46 neoplastic lesions 89.13% were malignant, while remaining were benign. RCC (n = 36) was the most common malignant lesion. Of 46 neoplastic lesions, 36 were RCC, 3 were renal oncocytoma, 2 each were transitional carcinoma and nephroblastoma, and the only case of mesoblastic nephroma. [Table 2] shows histological diagnosis and gender-based distribution of kidney lesions in 161 patients [Table 2].{Table 2}

Pyelonephritis (n = 114) was the most common cause for nephrectomy in our study of which majority were chronic pyelonephritis (n = 106) and maximum were stone related (n = 84) which lead to nonfunctioning of kidney [Table 2]. Gross appearance of the kidneys in Chronic pyelonephritis (CPN) showed polar scars, blunting of calyces, and loss of pyramids in the polar region. In some cases, CPN showed diffuse involvement of pyramids [Figure 1]a and [Figure 1]b. Histological sections showed the areas of fibrosis in the renal parenchyma, atrophic, or dilated tubules lined by flattened epithelium. Some tubules were filled by hyaline casts which is referred as thyroidization. There was dense inflammatory infiltrate of lymphocytes, histiocytes, and plasma cells. Peri glomerular fibrosis was seen in many cases [Figure 1]c and [Figure 1]d.{Figure 1}

Kidney specimens in 6 cases of xanthogranulomatous pyelonephritis showed lobulated yellowish external surface. Cut section of specimens showed extensive cortical atrophy, dilated pelvicalyaceal system with thick purulent material [Figure 2]a and [Figure 2]b. Multiple histology sections showed features of CPN described above and in addition, it showed many histiocytes with abundant foamy cytoplasm (Xanthoma cells) and focal polymorphonuclear leukocytes [Figure 2]c. Giant cells and cholesterol clefts were seen.{Figure 2}

All 2 cases of tuberculous pyelonephritis showed cheesy white areas on external surface and on dilated pelvi-calacyeal system [Figure 3]a. Microscopy showed caseating granulomas and Langhans giant cells. Both the patients did not have the evidence of pulmonary tuberculosis [Figure 3]b. The only case of ADPKD grossly showed multiple cysts on external surface and cut surface [Figure 3]c. Microscopic sections showed cysts of varying sizes lined by flattened epithelium [Figure 3]d.{Figure 3}

Important gross features in RCC included well-delineated tumor mass measuring between 5 and 9 cm in diameter located in upper pole. Cut surface of the tumors were solid with variable degenerative changes [Figure 4]a and [Figure 4]b. In 2 cases mass was in the middle and lower portion of the kidney. Size and extent of the spread of tumor will depend on the time of diagnosis. On histological examination, 27 cases showed large tumor cells with optically clear cytoplasm due to the accumulation of glycogen while some tumor cells showed granular eosinophilic cytoplasm. Nuclei were centrally located with variable size, chromatin pattern, and nucleolar appearance [Figure 4]c. The tumor cells were arranged either in solid sheets, or had alveolar and acinar patterns. Stroma showed network of thin-walled blood vessels. In three cases clear-cell RCC showed sarcomatoid differentiation [Figure 4]d. The five cases of papillary RCC showed thick fibrous capsule, complex papillary formations with cystic spaces. The stromal invasion was seen. Complex papillae were lined by pseudostratified cuboidal epithelium, and nuclei were pleomorphic and showed prominent nucleoli [Figure 4]e.{Figure 4}

Of 35 cases of clear cell and papillary RCC, the nuclear Grade 1 (n = 9) showed absent nucleoli or inconspicuous and basophilic at ×400 [Figure 5]a. Grade 2 (n = 17) showed conspicuous and eosinophilic nucleoli at ×400 and visible but not prominent at ×100 [Figure 5]b. Grade 3 (n = 6) showed conspicuous and eosinophilic nucleoli at ×100 [Figure 5]c. Grade 4 (n = 4) showed extreme nuclear pleomorphism and/or rhabdoid differentiation or sarcomatoid differentiation [Figure 5]d. In our study, one case which showed sarcomatoid differentiation had Grade 4 nuclear grading. Out of 30 clear-cell RCC, maximum (n = 14) were Grade 2, followed by (n = 8) Grade 1, (n = 5) Grade 3 and (n = 3) Grade 3 as per the WHO/ISUP nuclear grading system. Of 5 papillary RCC cases, 1 case each was Grade1 and Grade 3 and 3 cases were Grade 2 [Table 3]. Of 36 RCC, 8 RCC were Stage I, 20 RCC were Stage II, 5 were Stage III, and 3 cases were Stage IV. Two cases of nephroblastoma in our study were Stage II.{Figure 5}{Table 3}

The only case of chromophobe RCC in our study showed well-delineated mass and cut section was homogenous and gray-brown [Figure 6]a. Histologic sections showed tumor cells with sharply defined borders, abundant cytoplasm with prominent cell membrane, and perinuclear hallow [Figure 6]b. We came across two cases of transitional cell carcinoma which were arising from the renal pelvis. Microscopy showed solid sheets of urothelial cells showing moderate nuclear pleomorphism, hyperchromatic nuclei, and prominent nucleoli. Increased mitotic figures were seen [Figure 6]c. One case of squamous cell carcinoma showed squamous cells with moderate pleomorphism, hyperchromatic nuclei, prominent nucleoli, and increased mitotic figures. The tumor cells were infiltrating the renal parenchyma [Figure 6]d.{Figure 6}

Out of 46 neoplastic lesions, we came across 2 (4.34%) cases of nephroblastoma. Both the tumors were grossly large well-circumscribed replacing almost entire kidney. The cut section showed variegated solid grayish tan color [Figure 7]a. Histopathological examination showed diffuse sheets of round-to-oval primitive cells with scant cytoplasm (undifferentiated blastemal), spindle cells with elongated nuclei (mesenchymal tissue) and epithelial components in the form of embryonic tubules and glomerular structures [Figure 7]b.{Figure 7}

All three cases of renal oncocytoma grossly showed well-circumscribed, unencapsulated, solid, homogenous, mahogany lesion of about 3 cm with a central scar [Figure 7]c. Microscopy showed cells with abundant acidophilic granular cytoplasm, growing in a nesting alveolar pattern. The nuclei were small round and regular [Figure 7]d.

The only case of angiomyolipoma showed a tumor mass which was partially encapsulated measuring 21 cm × 20 cm and cut section showed was solid with yellowish and hemorrhagic areas [Figure 8]a. Histopathology sections showed admixture of blood vessels and tumor cells composed of eosinophilic spindle cells showing myoid features and cells with clear cytoplasm mimicking adipocytes [Figure 8]b. The spindle cells were positive for HMB45 and smooth muscle antigen (SMA). The tumor was histologically limited to kidney.{Figure 8}

The only case of mesoblastic nephroma in nephrectomy specimens showed well-circumscribed gray yellow solid tumor at hilus [Figure 8]c. Histopathological examination showed features of mesoblastic nephroma such as intersecting fascicles of elongated spindle cells with intercellular collagen with entrapped tubules and glomeruli [Figure 8]d. There was no mitotic activity.


Kidneys can be affected by both neoplastic and non-neoplastic conditions that require nephrectomy. There was no predilection of lesions to the right or left kidney. None of our patients underwent bilateral nephrectomies. In our study, the nephrectomy for non-neoplastic lesions was done at a younger age. Datta et al.[10] in their study observed mean age of 47.5 (range: 17–69 years) for nephrectomies which was similar to our study. In contrast, Ibrahim et al.[11] observed mean age of 28.7 years for nephrectomies in their study. The mean age for nephrectomies in males was 49.32 years (SD ± 20.25) which was more than females (41.5 years, SD ± 17.71). Maximum nephrectomies (n = 58) were done in the age group of 30–49 years [Table 1]. In contrast, many studies found 41–60 years as the commonest age group for nephrectomies.[2],[5],[6],[7],[8] Possible reason can be geographical variation in the age group and time at which patients visited hospital.

The incidence of nephrectomies due to non-neoplastic conditions, especially chronic pyelonephritis has decreased as compared to malignant lesions in some developed countries.[3],[12],[13],[14] However, in our study, pyelonephritis was the most common cause of nephrectomy. Similar observations were seen in many studies from Asian countries.[4],[11] A possible reason for change in the trend can be early detection and better treatment modalities of inflammatory lesions of the kidney in the developed countries as compared with developing countries.

Pyelonephritis refers to an inflammatory process involving renal tubules, interstitium, and renal pelvis. It is one of the common diseases of the kidney. It occurs in two forms. Acute pyelonephritis is caused by bacterial infection of the urinary tract. While in Chronic pyelonephritis bacterial infection plays a dominant role and other factors such as vesicoureteral reflux and obstruction also play a role in pathogenesis. The gross appearance of the kidneys varies according to etiology. CPN due to vesicoureteral reflux shows polar scars because papillae are involved in these which lead to blunting of calyces and loss of pyramids in the polar region. In contrast, CPN due to obstruction shows diffuse involvement of pyramids.[11] Similar observations were made in our study In 22 patients there was no evidence of stone or obstruction in the urinary tract. Possible reason in these patients can be presence of vesicoureteral reflex which leads to chronic inflammation, end-stage renal disease, and eventually nonfunctioning of the kidney.

Xanthogranulomatous pyelonephritis is a rare, distinct, and aggressive form of chronic pyelonephritis and if uncontrolled it spreads to adjacent tissues and destroys it. Urinary obstruction is almost invariably present and most often caused by renal stones. It accounts for <1% of chronic pyelonephritis.[15],[16] In our study, we came across more number of cases, possible reason can be geographical variation of the lesion. In contrast, Avasthi[17] Ngairangbam and Konjengbam[7] and Vinay and Sujatha[8] observed higher percentage in their study. Amina et al.[6] and Shaila and Arasi[5] observed lower percentage of 1.42% and 1.88%, respectively. Although it can occur at any age, it is more common in fifth and seventh decades and common in women than men.[18] Similar observations were made in our study. No clinical or radiological features are diagnostic of xanthogranulomatous pyelonephritis (XPN) and preoperatively, they are often misdiagnosed with chronic pyelonephritis or tuberculosis or perinephric abscesses or RCC.[19],[20] The CT scan is the mainstay of diagnostic imaging for XPN. It is essential to diagnose these cases early so as to prevent complications such as psoas abscess, enterocolonic fistulas, perinephric abscess, and sepsis. None of our patients developed these complications preoperatively or postoperatively.

Tuberculosis is a worldwide problem. Extrapulmonary tuberculosis is on the rise worldwide, especially in countries with a high prevalence of pulmonary tuberculosis. Many studies found relatively higher prevalence in their study as compared to our study.[3],[4],[13],[21] Possible reason can be geographical variation and the type of patients we came across in our study.

ADPKD is one of the most common hereditary human disorders and it occurs in about 1 or 2 per thousand live births. About 10% cases require dialysis or renal transplantation. We came across with only one case of ADPKD.

RCC mainly occur in adults with an average age of 55–60 years at the time of diagnosis but they can occur in children. They are more common in males than females with 2:1 male-to-female ratio. The incidence of bilaterality is 1%. In our study, there was no bilateral involvement of kidneys by RCC. With increasing use of CT scan and MRI, the number of incidentally detected RCCs has increased substantially.[22] However, none of cases in our study was incidentally detected in our study possible reason can be, patients might have come to our center at the later stage of the disease. The classical clinical diagnostic triad of hematuria, flank pain, and abdominal mass have been described.[23] In our study, they were seen in 10 cases of RCC.

Various histological subtypes of RCC have been described such as clear cell, papillary, chromophobe, collecting duct, renal medullary carcinoma, tubulocystic carcinoma, mucinous tubular, and spindle cell RCC. Diagnosing specific subtypes is important because each has distinct underlying molecular subtypes, unique immunophenotypes, varying biologic potential for aggressive behavior, and emerging therapeutic implications. On histopathological sections, out of 36 cases of RCC majority were clear-cell RCC (n = 30) [Table 3].

Nuclear grade has proven of great utility in clear-cell RCC and papillary RCC and is an important predictor of survival which strongly correlates with the surgical staging. Grading was done in microscopic sections by using the WHO/ISUP grading system. The staging of RCC was done by TNM classification as per the WHO 2016 and correlated well with nuclear grading in our study.

Primary squamous cell carcinoma rarely appears in upper urinary tract. We came across only one case of primary squamous cell carcinoma which was arising from renal pelvis.

Nephroblastoma is the most common childhood malignant tumor. Possible variation can be due to the type of patients we came across. It is seen primarily in infants and 50% occur before the age of 3 years and 90% before the age of 6 years. Ibrahim et al.[11] and Salma et al.,[24] Amina et al.[6] reported higher prevalence of nephroblastoma ranging from 55.56% to 18.19% in their study. Both the patients in our study were 5- and 6-year-old, respectively Both the tumors were confined to the kidney and did not reveal lymph node metastasis and were staged as stage I as per staging system by Children's oncology group.

Of 5 benign lesions, three were renal oncocytoma and one each was of angiomyolipoma and mesoblastic nephroma. Renal oncocytoma is controversial and problematic for diagnosis in renal cell neoplasia classification today. All were classified as classical oncocytoma.

Primary angiomyolipoma is a morphologically heterogeneous entity. It mostly occurs in adults and can be found incidentally or result in retroperitoneal hemorrhage. CT scan findings of a patient revealed a nonfunctioning kidney and a large mass with mixed density arising from kidney. When the tumor reaches >10 cm it is called giant angiomyolipoma.[25] In our study, tumor was confined to kidney.

The only case of congenital mesoblastic nephroma in our study was in a 1-month female child who was admitted with abdominal distension. CT scan revealed heterogeneous tumor and suggested neoplastic lesion. Congenital mesoblastic nephroma is the most common type of renal tumor in newborn and infants under 3 months of age and 90% cases occur under the age of 1 year. The local rate of recurrence in congenital meroblastic nephroma is 5%, commonly due to incomplete resection. Our patient showed no recurrence.


There is a change in the indication of nephrectomy in some Western countries during the past few decades. Nephrectomy is commonly done for malignant conditions. However, in developing countries like India, chronic pyelonephritis remains the most common cause of nephrectomy. Maximum patients were having stone related problems which lead to nonfunctioning kidney. A substantial number of these patients were in the age group of 20–39 years and maximum were females. Better treatment modalities for inflammatory lesions of kidney in the developing countries will reduce the rate of nephrectomies.

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Conflicts of interest

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