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Saudi Journal of Kidney Diseases and Transplantation
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CASE REPORT Table of Contents   
Year : 2010  |  Volume : 21  |  Issue : 4  |  Page : 728-731
Intrarenal epidermoid cyst presented as an enlarged multicystic kidney

Department of Pathology, Faculty of Medicine, Menofiya University, Shebein Elkom, Egypt

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Date of Web Publication26-Jun-2010


This report describes a case of large multiple and multilocular epidermoid cysts affecting the left kidney of a 67 old male. The condition was accidentally discovered during the ultrasonography for left loin pain and revealed enlarged left kidney with picture suggestive of hydronephrosis. Grossly, the kidney was distorted cysts that were filled with a cheesy material. The histologic picture of an end stage kidney disease was apparent in the compressed renal parenchyma by these cysts that were identical to an epidermoid cyst elsewhere. In conclusion, although rare, epidermoid cyst of the kidney could cause serious kidney damage leading to an end stage kidney disease. Epidermoid cyst of the kidney could be multiple producing a picture similar to hydronephrosis andbroadening the differential diagnosis of multicystic disease of the kidney.

How to cite this article:
Abdou AG, Asaad NY. Intrarenal epidermoid cyst presented as an enlarged multicystic kidney. Saudi J Kidney Dis Transpl 2010;21:728-31

How to cite this URL:
Abdou AG, Asaad NY. Intrarenal epidermoid cyst presented as an enlarged multicystic kidney. Saudi J Kidney Dis Transpl [serial online] 2010 [cited 2022 Aug 16];21:728-31. Available from: https://www.sjkdt.org/text.asp?2010/21/4/728/64661

   Introduction Top

Epidermal inclusion cyst refers to those cysts that arise from the implantation of epidermal elements in the dermis. However, many cysts originate from the infundibular portion of the hair follicle, and the more general term, epi­dermoid cyst, is favored. The typical epider­moid cyst is lined with stratified squamous epithelium that contains a granular layer and is filled with keratinous material that is often in a laminated arrangement. Intrarenal epidermoid cyst is a very rare condition with few reported cases in the English literature [1],[2],[3],[4] [Table 1]. It is also reported to arise in the renal pelvis and upper ureter with only four cases mentioned in the literature. [5],[6],[7],[8]

In this report we present an accidentally dis­covered case of extensive left kidney destruc­tion replaced by boggy multilocular cysts pa­thologically proved to be an epidermoid cyst.

   Case Report Top

A 67-year-old male patient suffered from left loin pain after previous blunt trauma. No pre­vious history of upper or lower urinary tract stones. Ultrasonography revealed markedly en­larged hydronephrotic left kidney with evidence of rupture that necessitated left nephrectomy. Gross examination revealed that the kidney was enlarged, distorted and measured 20 Χ 15 Χ 10 cm. Its cut section showed replacement of kid­ney tissue by multiple pockets & cavities filled with firm cheesy material and absence of grossly identified stones [Figure 1]. Microsco­pically, the renal parenchyma was compressed by these multiple and multilocular cysts that were lined by keratinized stratified squamous epithelium with granular cell layer and filled with laminated layers of keratin [Figure 2] and [Figure 3]. No evidence of skin appendages either pilosebaceous units or eccrine sweat glands were noticed. The surrounding renal pa­renchyma showed signs of atrophy in the form of decreased number of glomeruli that appeared mostly sclerosed and hyalinized. In addition to the atrophy of the tubules that appear small in size and filled with colloid like casts (tubular thyroidization) [Figure 4]. This atrophic paren­chyma was either seen directly beneath the cyst wall or separated from it by areas of fat or fibrosis. Considerable foreign body granulo­matous reaction was also recognized. The pelvi­ureteric junction was lined by normal transi­tional urothelium without any evidence of squa­mous metaplasia.

   Discussion Top

In our patient, the left kidney was studded by multiple cysts replacing and compressing the whole renal parenchyma that was diagnosed as hydronephrosis by ultrasound. The definitive diagnosis was reached by the microscopic iden­tification of the skin layered filled cysts that lacked skin appendages. On the other hand, in the previous described cases, the intrarenal epidermoid cyst was single and affecting one pole of the kidney that was suspected to be a renal neoplasm preoperatively. [1],[2],[3],[4] In our case as well as the previous reported ones, the diagnosis could not be made preoperatively and not even suspected.

The presence of stratified squamous epithe­lium in renal lesions is considered as a rare condition which may have different causes. For example, extension of squamous metaplastic changes from the upper ureter to the pelvi­calyceal system in prolonged obstructive con­ditions induced mostly by stones is considered as one of the commonest source of squamous epithelium in the kidney. [9] This metaplastic epithelium may be a precursor for the very rare primary renal squamous cell carcinoma. [10] Squa­mous epithelium could also be a part of other renal lesions such as teratoid variant of Wilm's tumor, [11] teratoma [12] and dermoid cyst. [13]

In the current study, the absence of renal calculi and metaplastic changes in the pelvi­ureteric junction could differentiate our case from the squamous metaplasia of the pelvi­calyceal system due to the obstructive and irri­tative effects of stones. Furthermore, the con­finement of this cystic structure to the epi­dermal lineage with the absence of other li­neages of differentiation together with the lack of other cutaneous adenexal structures helped in differentiating from teratoma and dermoid cyst.

Different theories had been suggested for the presence of epidermoid cyst in extraordinary sites such as internal solid organs including kidney, spleen, brain and testis. If the implan­tation, sequestration or inclusion could be sui­table explanations for epidermoid cyst arising in hairy and in non hairy areas, [4] it would not be acceptable in internal organs except after exclusion of trauma. In kidney, it is suggested that this type of cyst could originate from the embryonic remnant of Wolffian ducts and this hypothesis is considered as the most con­venient one. [4] Inclusion of surface mesothelium in splenic parenchyma could be the source of epidermoid cyst in the spleen. [14] (Epidermoid cyst could arise in brain or cavernous sinus from subpopulation of neural crest cells that remain entrapped within the meninges in un­complicated stage of maturation. [15] Epidermoid cyst could also develop in testis as an epi­dermal differentiation of monodermal teratoma referring to its germ cell origin. [16] Squamous metaplasia of the rete testis could be another explanatory pathway for its development in testis. [16]

In conclusion, epidermoid cyst of the kidney is a rare condition causing severe kidney damage leading to an end stage kidney disease. Epidermoid cyst of the kidney could be mul­tiple producing a picture similar to hydroneph­rosis. Awareness of the occurrence of this cyst would broaden the differential diagnosis in unilateral cystic diseases of the kidney.

   References Top

1.Krogdahl AS. Epidermoid cyst in the kidney. Scand J Urol Nephrol 1979;13:131-2.  Back to cited text no. 1  [PUBMED]    
2.Duprat G, Filiatrault D, Michaud J. Intrarenal epidermoid cyst. Pediatr Radiol 1986;16:73-5.  Back to cited text no. 2      
3.Emtage LA, Allen C. A renal epidermoid cyst. Br J Urol 1994;74:125-6.  Back to cited text no. 3  [PUBMED]    
4.Lim SC, Kim CS. Intrarenal epidermal cyst. Pathol Int 2003;53:574-8.  Back to cited text no. 4  [PUBMED]  [FULLTEXT]  
5.Boeminghaus F, Huth F. Epidermoid cyst of the kidney pelvis wall (Clinical, histo­pathological and cytological findings). Z Urol Nephrol 1971;64:829-34  Back to cited text no. 5      
6.Salgarello G, Pigliucci GM. A rare case of epidermoid cyst of the renal pelvis. Chir Patol Sper 1980;28:311-7.  Back to cited text no. 6  [PUBMED]    
7.Gokce G, Kaya K, Kilicarslan H, et al. Epi­dermoid cyst in the renal pelvis. Int Urol Nephrol 2003;35:9-10.  Back to cited text no. 7  [PUBMED]  [FULLTEXT]  
8.Ishizaki H, Iida S, Koga H, Shimamatsu K, Matsuoka K. Epidermoid cyst of the ureter: A case report. Int J Urol 2007;14:443-4.  Back to cited text no. 8  [PUBMED]  [FULLTEXT]  
9.Boswell PD, Fugitt B, Kane CJ. Keratinizing desquamative squamous metaplasia of the kidney mimicking transitional cell carcinoma. Urology 1998;52:512-3.  Back to cited text no. 9  [PUBMED]  [FULLTEXT]  
10.Karabult A, Emr L, Gonulta M, Incel N, Germiyanoglu C, Eroll D. Squamous cell car­cinoma located in the renal calyceal system: A case report and review of the literature. Turk J Cancer 2002;32:20-4.  Back to cited text no. 10      
11.Inoue M, Uchida K, Kohei O, et al. Teratoid Wilms' tumor: a case report with literature review. J Pediatr Surg 2006;41:1759-63.  Back to cited text no. 11  [PUBMED]  [FULLTEXT]  
12.Mochizuki K, Ohno Y, Tokai Y, et al. Conge­nital intrarenal teratoma arising from a horse­shoe kidney. J Pediatr Surg 2006;41:1313-5.  Back to cited text no. 12  [PUBMED]  [FULLTEXT]  
13.Otani M, Tsujimoto S, Miura M, Nagashima Y. Intrarenal mature cystic teratoma associated with renal dysplasia: case report and literature review. Pathol Int 2001;51:560-4.  Back to cited text no. 13  [PUBMED]  [FULLTEXT]  
14.Maskey P, Rupakheti S, Regmi R, Adhikary S, Agrawal CS. Splenic epidermoid cyst. Kath­mandu Univ Med J 2007;18:250-2.  Back to cited text no. 14      
15.Tatagiba M, Iaconetta, Samii M. Epidermoid cyst of the cavernous sinus: clinical features, pathogenesis and treatment. Br J Neurosurg 2000;14:571-5.  Back to cited text no. 15      
16.Loya AG, Said JW, Grant EG. Epidermoid cyst of the testis: radiologic-pathologic corre­lation. Radiographics 2004;24(Suppl 1):S243-6.  Back to cited text no. 16  [PUBMED]  [FULLTEXT]  

Correspondence Address:
Asmaa Gaber Abdou
Department of Pathology, Faculty of Medicine, Menofiya University, Shebein Elkom
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Source of Support: None, Conflict of Interest: None

PMID: 20587881

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  [Figure 1], [Figure 2], [Figure 3], [Figure 4]

  [Table 1]

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Urology. 2011; 78(3): 563-564


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