Histopathological spectrum of renal tumors in nephrectomy specimens

Introduction: Kidneys are the vital organs of the body which are having multiple functions. The benign or malignant diseases of the kidney result in total organ removal. Renal tumors comprises a wide spectrum of neoplastic lesions with patterns that are distinct for children and adults. In India management of chronic kidney diseases is a great challenge as the dialysis and kidney transplantations are expensive. Objectives: To study histopathological features of various renal tumors in nephrectomy specimens and to determine the age and sex distribution in various renal tumors Materials and Methods: The study was done in Mysore medical college and research institute. Total 14 nephrectomy cases were studied in a period of 2 years from 2015 to 2017. Results: Total 14 renal tumors were studied. In which RCC is the most common -10 cases, followed by SCC and Angiomyolipoma, 2 cases each. Most of the patients presented in age group of 4th to 5th decade with male to female ratio of 1.16:1. Histologically RCC-clear cell type was the most common subtype Conclusion: RCC is the most common renal tumors in which clear cell type is most common subtype.


Introduction
Kidneys are the vital organs of the body which are having multiple functions.
Their main function is not only excretion but they also maintain water and salt metabolism along with acid base balance, they are going to maintain the blood pressure through reninangiotensin mechanism and hematopoiesis by producing erythropoietin. 1 Like other organs in human body, kidneys also involved by many benign or malignant diseases which requires total organ removal. Simple nephrectomy is done to remove non functioning kidneys which are irreversibly damaged by different benign pathological conditions and On the other hand for different malignant conditions of the kidney radical nephrectomy is indicated. 2 Renal tumors comprise a wide spectrum of neoplastic lesions with patterns that are distinct for children and adults. A wide variety of benign and malignant tumors arises from the renal parenchyma. 3 Surgery remains the standard of treatment for localised RCC. Nephron sparing surgery is favoured for small, organ-confined tumors. New techniques, such as cryoablation and radiofrequency ablation which are minimally invasive, have shown good results and the followup is still short. 4

Materials and Methods
This is a cross section study undertaken in the department of pathology, Mysore Medical College and Research Institute for duration of 18 months from December 2015 to May 2017. A total number of 50 cases were studied.
Detailed clinical history of the patients were collected while receiving the specimen and by checking the medical records. All nephrectomy specimens were fixed in 10% formalin and then subjected to gross examination, noting the size, appearance, external surface and cut surface. Representative bits were taken, processed and stained with routine Hematoxylin and Eosin and other special stains wherever required. All sections were studied and clinicopathological evaluation of nephrectomy specimens were done. Tumors were further classified according to 2016 WHO classification.

Results
This study is done in Mysore Medical College and Research Institute where total of 14 cases of renal tumor were studied. Renal cell carcinoma (RCC) was the commonest tumor seen in the present study and was found to be frequent in 4th and 5th decade. It comprised of 20% (10/50) of all the renal lesions and 71.4% (10/14) of the neoplastic lesions of the kidney. Two cases of squamous cell carcinoma and angiomyolipoma were seen each comprised of 14.3% each. Squamous cell carcinoma was seen in the 4th and 5th decade. Angiomyolipoma was seen in 3rd and 4th decade. Table 1 shows the frequency of neoplastic lesions in relation to sex. Renal cell carcinoma was equally distributed in both sex (male: female ratio-1:1). Two cases of squamous cell carcinoma was seen in male. Two cases of Angiomyolipoma was seen in female. Table 2 illustrates the macroscopic features of the kidney in renal cell carcinoma. Kidney was enlarged in all cases. The most frequent finding was the presence of haemorrhagic and necrotic areas. Cystic degeneration was present in 50% of the cases. Table 3 illustrates the frequency of various histological variants of renal cell carcinoma The most common subtype encountered was clear cell type comprising of 5 out of 10 cases of RCC followed by papillary variant which comprises of 4 cases. Chromophobe variant was seen in 1 case. Table 4 shows the microscopic features of renal cell carcinoma. In clear cell RCC out of 5 cases 3 cases exhibited Furhman nuclear grade 3 and 2 cases shows Furhman nuclear grade 2. Chromophobe RCC exhibits Furhman nuclear grade 2. In Papillary RCC out of 4 cases 3 exhibits Furhman nuclear grade 4 and 1 case exhibits Furhman nuclear grade 3. One case of papillary RCC showed lymphatic infiltration. Squamous Cell Carcinoma: Two case of SCC is were seen. Grossly both are enlarged, tumor proper seen which is involving almost entire kidney, areas of haemorrhage and necrosis is seen. Microscopically squamoid cells with increased N:C ratio, prominent nucleoli and moderate amount of cytoplasm. Also seen are areas of necrosis. Angiomyolipoma: One case of classical and one case of epitheloid Angiomyolipoma. Grossly both were enlarged, cut section shows multiple yellowish areas. Microscopically fatty tissue, blood vessels and muscle component seen in both the cases. Epitheloid cells are seen in epitheloid variant of angiomyolipoma. Table 5 shows that majority of the RCC were presented in Stage I (50%, 5/10), followed by Stage II (40%, 4/10) and 1 case in stage III. 2 cases of SCC is in stage II. Table 6 shows the clinical presentation neoplastic lesions: RCC: All cases presented with pain abdomen and haematuria. 8 cases were with mass per abdomen SCC: There was 2 cases of SCC who presented with pain abdomen, mass per abdomen and hematuria.
Angiomyolipoma: There were 2 cases both the cases presented in pain abdomen and 1 case presented with mass per abdomen and haematuria.

Discussion
Histopathology is an important and useful learning tool in the hands of pathologists to study the spectrum of diseases.
Radical nephrectomy (RN) was first described by Robson in 1963, it has been described as the standard surgical treatment of kidney cancer. 5 In this study Renal cell carcinoma is most common renal tumor which is similar to Aiffa Aiman et al 6

Angiomyolipoma
In this study there are 2 cases (4% of total nephrectomy and 14.28% of neoplastic lesion) of Angiomyolipoma with female predominance all the 2 cases were seen in females and of age 35 and 50years. In this one is classical and another is epitheloid angiomyolipma Microscopically, the tumors were composed of mature adipose tissue, tortuous thick-walled blood vessels and bundles of smooth muscle that seem to emerge from the vessel walls which were in accordance with the literature review.
In a study done by Shaila et al 1 and Aiman A et al 11 1.87% and 0.7% with female predominance.

Conclusion
Renal cell carcinoma was the commonest renal tumor encountered followed by SCC and Angiomyolipoma, 2 cases each. The most common presenting feature of Renal cell carcinoma was pain abdomen and hematuria followed by mass per abdomen. Most commonly affected males were in age group of 4 -5 th decade.

Conflict of Interest:
None.