LETTER TO EDITOR
Year : 2008 | Volume
: 51 | Issue : 4 | Page : 563--565
Multilocular cystic nephroma of the kidney
Rashmi Patnayak1, Mandyam Kumaraswamy Reddy1, S Subramanian2, G Ravisankar2,
1 Department of Pathology, Sri Venketeswar Institute of Medical Sciences, Tirupati, Andhra Pradesh 517 507, India
2 Department of Urology, Sri Venketeswar Institute of Medical Sciences, Tirupati, Andhra Pradesh 517 507, India
Department of Pathology, Sri Venketeswar Institute of Medical Sciences, Tirupati, Andhra Pradesh 517 507
|How to cite this article:|
Patnayak R, Reddy MK, Subramanian S, Ravisankar G. Multilocular cystic nephroma of the kidney.Indian J Pathol Microbiol 2008;51:563-565
|How to cite this URL:|
Patnayak R, Reddy MK, Subramanian S, Ravisankar G. Multilocular cystic nephroma of the kidney. Indian J Pathol Microbiol [serial online] 2008 [cited 2021 Apr 15 ];51:563-565
Available from: https://www.ijpmonline.org/text.asp?2008/51/4/563/43765
Multilocular cystic nephroma is a rare benign renal tumor, which usually presents with a clinical picture and radiological feature indistinguishable from malignant renal neoplasms. Cystic nephroma has been identified as an exclusively adult lesion, which is predominantly seen in females.  It commonly occurs as an asymptomatic mass, occasionally with hematuria. The tumor is usually slow growing but occasional rapid growth is observed. The etiology and pathogenesis of multicystic nephroma is not clear.
We report two cases of multicystic nephroma in adult patients. The first case was a 33-year-old female who presented with a history of abdominal pain of 6 months duration. The second case was a 16-year-old female who presented with swelling and discomfort in the right hypochondriac region for the last 2 years. In both the cases, there was no history of hematuria. There was no history of any obstructive or irritative voiding symptoms. There was no relevant family history. On examination, there was a soft palpable mass in the right hypochondrium and right lumbar region. Computerized tomography (CT) scans revealed mixed density, a heterogeneously enhancing mass lesion involving the interpolar and lower pole parenchyma of the right kidney with a compressed and medially displaced renal pelvis. [Figure 1a],[Figure 1b],[Figure 1c]. Radical nephrectomy was performed because of the clinical suspicion of renal cell carcinoma.
The nephrectomy specimens in both the cases revealed multiloculated cysts occupying almost the entire renal substance. The size of cysts varied from 0.1 cm to 1.5 cm in diameter. The contents of the cysts were clear watery fluid. The cystic lesion was well confined to the renal capsule and clearly demarcated from the remnant of adjacent normal looking renal parenchyma [Figure 2].
Microscopically, the cysts were lined by flattened, cuboidal, and hobnail type of epithelial cells [Figure 3] and [Figure 4]. The stroma in between the cysts comprised of fibrous tissue without any epithelial component. Immunohistochemistry results showed positivity for the mesenchymal marker vimentin in the stromal tissue whereas the epithelial lining was positive for epithelial markers.
Edmunds originally described cystic nephroma in 1892 as a "cyst adenoma".  Adults can present with a variety of nonspecific signs and symptoms, including abdominal and flank pain, urinary tract infection, and hypertension. Hematuria, either microscopic or gross, can occur. The most commonly reported location for this tumor originates at the lower pole, although tumors have been known to originate in other areas. Ultrasounds, CT scans, and MRIs are helpful in revealing the multilocular cystic nature of the lesion and its contents, but cannot distinguish multilocular cystic nephroma from other entities with similar presentation. Multilocular cystic nephroma is a distinct renal tumor whose gross external appearance and absence of normal renal tissue within the septa of loculi distinguish it clearly from other renal cystic lesions. The differential diagnosis includes a Cystic Partially differentiated nephroblastoma (CPDN) and a cystic renal cell carcinoma. The final diagnosis is obtained by histological examination of the resected specimen. Microscopically, in multilocular cystic nephroma, the locules are lined by flattened cuboidal or hobnail type of epithelium. The fibrous septa lack the blastemal or other embryonal elements found in CPDN but may contain well-differentiated renal tubules. In multilocular renal cell carcinoma, single or several layers of neoplastic epithelial cells usually line the cysts. In the past, multilocular cystic renal tumors have been considered to be lesions of developmental origin, hamartomas, or hamartomas with malignant potential. Joshi and Beckwith emphasized a neoplastic rather than a developmental or hamartomatous origin.  Because it is difficult to distinguish a multilocular renal cyst from cystic Wilms' tumor and multicystic clear cell carcinoma on the basis of imaging studies alone, surgical intervention is the only effective method, which is curative either with nephrectomy or with nephron-sparing surgery. No metastases have been reported following surgical resection. Another important differential diagnosis of cystic nephroma is Mixed Epithelial Stromal Tumor (MEST). A MEST is a benign biphasic tumor, which contains epithelial and spindle cell stromal components. Both lesions affect adults with female predominance and share several overlapping clinical and morphologic features. Grossly, both lesions are all well circumscribed. MESTs are typically composed of multiple cysts and solid areas, whereas cystic nephroma is composed entirely of cyst and cyst septa without solid areas.  According to Antic, et al. , a MEST and cystic nephroma represent the opposite ends of the spectrum of the same lesion. While cystic nephroma may be found in both sexes with no history of estrogen use and/or obesity, MESTs are tumors that acquire cellular, ovarian-like stroma as a result of hormonal influence. 
This article reports multilocular cystic nephroma in adult patients to bring awareness about the benign nature of this condition and to differentiate it from renal cell carcinoma. Both the patients had an uneventful recovery after undergoing nephrectomy.
The authors wish to thank senior technicians Mrs. Ushanandini and Mr. Ramana for their help.
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