Cystic Nephroma: Cytologic Findings in Fine-Needle Aspiration Cytology Ricardo Drut, M.D.

This report presents the fine-needle aspiration cytology (FNA C) findings of a multicystic renal tumor found in a 3-year-old child. The smears contained benign epithelial cells isolated or arranged in sheets of uniform cells strongly suggesting the lining of the cysts. The combination of the imaging data with the FNACfindings favoured the diagnosis of cystic nephroma (CN), a benign renal tumor that is cured by surgery. Surgical pathology confirmed the diagnosis. CN should be added to the list of tumors of the kidney in infancy that appear to be diagnosable by FNAC/biopsy. Diagn Cytopathol 1992;8:593-595. 0 1992 Wiley-Llss, Inc Key Words: FNAC; CN; Renal tumor

Several recent studies have described the cytologic features of different renal neoplasms in children (1-7) However, there is no report dealing with the cytologic findings of cystic nephroma (CN). This is an infrequent benign lesion, which should be separated from the so-called cystic partially differentiated nephroblastoma (see Discussion for differential diagnosis). Although both have good prognosis, the infrequent benign lesion does not require any other treatment but surgery, and, of course, preoperative chemotherapy is not indicated.

Case Report and Cytologic Findings A 3-year-old boy was admitted to the hospital with a tumor in the left kidney. Ultrasound and CT scan showed a large multicystic tumor extensively septated (Fig. 1). Through percutaneous fine-needle aspiration cytology (FNAC), 4 ml of yellowish fluid were obtained. Ethanol 96-fixed, hematoxylin-eosin-stained smears of this fluid showed a few small sheets of orderly arranged, nonmalignant epithelial cells. The cells were uniform, had round homogeneously staining nuclei and scant cytoplasm, and Received July 26, 1991. Accepted January 8, 1992. From the Servicio de Patologia, Hospital de Nifios, La Plata, Argentina. Address reprint requests to Dr. Ricardo Drut, Servicio de Patologia, Hospital de Niiios, 1900 La Plata, Argentina. @I


Fig. 1. C T scan of the multicystic tumor of the kidney. Thin septa form the walls of the cysts.

strongly suggested that they were the lining of cysts. Also present were isolated epithelial cells with round to oval nuclei and pinkish large cytoplasm. The background was faintly proteinaceous (Fig. 2). A nephrectomy was performed on the patient 2 days later.

Pathology Findings The resected kidney contained a 10 X 10 X 8 cm, welldelimitated multicystic tumor. The cysts were separated by thin septa and contained clear yellowish fluid. Some septa were wider and seemed to be composed by myxoid tissue (Fig.3). The lesion was partially herniated into the pelvicaliceal system. Histologically there were septa containing loose conective tissue with an occasional tubule lined by benign epithelial cells. The cysts were partially lined by cuboidal and hobnail epithelial cells, whereas some areas had flat epithelium (Fig.4). There was a sharp demarcation between the tumor and the adjacent compressed kidney parenchyma.

Discussion FNAC appears to be an extremely useful tool for proper preoperative diagnosis of tumors of the kidney in infancy Diagnostic Cytopathology, Vol 8, No 6



Fig. 2. Smear of the F N A showing small and large sheets of epithelial cells suggesting the lining of a cyst (H-E, X 40). Insets: Isolated and grouped larger epithelial cells probably representing the hobnail type of epithelium ( X 400).

Fig. 3. Gross of the CN. Numerous cysts are separated by thin myxoid septa. Part of the lesion protrudes into the pelvicaliceal cavities (arrow). The remaining renal parenchyma shows hydronephrosis.


and childhood. Several recent reports have shown that each histologic variant seems to be readily diagnosable by this procedure. CN seems yet another type of kidney tumor that, in combination with imaging techniques, may be recognized by FNAC since the above described features 594

Diagnostic Cytopathology, Vol 8,No 6

Fig. 4. Microscopic section of the CN. Two epithelial-lined cysts are separated by a septum composed by loose connective tissue (H-E, X40).

are unique in the repertoire of cytologic characteristics of such tumors. This appears particularly important for those treatment protocols that use preoperative chemotherapy for kidney malignancies. In our case, the combination of imaging techniques and FNAC decided for


immediate surgery, avoiding potentially dangerous treatments. Differential diagnosis between CN and cystic partially differentiated nephroblastoma depends on the histologic recognition of islands of renal blastema and immature glomerular and tubular structures in the cysts septa. To my knowledge, there is no report dealing with the FNAC features of cystic partially differentiated nephroblastoma. Cystic nephroblastoma is yet another “cystic” tumor of the kidney, which although rare may present to differential diagnosis. This variety is a nephroblastoma with cysts. Most probably this type of neoplasm will yield a classical nephroblastoma smear.

References 1. Quijano G, Drut R. Cytologic characteristics of Wilms’ tumors in fine needle aspirates: a study of 10 cases. Acta Cytol 1989;33:263-6.

2. Akhtar M, Ali MA, Sackey K, Sabbah R, Burgess A. Aspiration cytology of Wilms’ tumor. Diagn Cytopathol 1989;5:269-74. 3. Drut R,Pollono D. Anaplastic Wilms’ tumor first suggested by fine needle aspiration cytology and biopsy. Acta Cytol 1987;31:774-6. 4. Drut R. Malignant rhabdoid tumor of the kidney diagnosed by fine-needle aspiration cytology. Diagn Cytopathol 19906:124-6. 5 . Akhtar M, Ali MA, Sackey K, Bakry M, Burgess A. Fine-needle aspiration biopsy diagnosis of malignant rhabdoid tumor of the kidney. Diagn Cytopathol 1991;7:3640. 6. Akhtar M, Ah, MA, Sackey K, Sabbah R, Bakry M. Fine needle aspiration biopsy of clear cell sarcoma of the kidney. Light and electron microscopic correlations. Diagn Cytopathol 1989;5:181-5. 7. Drut R. Cytologic characteristics of clear cell sarcoma of the kidney (CCSK) in fine-needle aspiration biopsy (FNAB): a report of 4 cases. Diagn Cytopathol 1991;7:611-614. 8. Joshi VV, Beckwith JB. Multilocular cyst of the kidney (cystic nephroma) and cystic, partially differentiated nephroblastoma. Terminology and criteria of diagnosis. Cancer 1989;64:466-79. 9. Domizio P, Risdon RA. Cystic renal neoplasms of infancy and childhood: a light microscopical, lectin histochemical and immunohistochemical study. Histopathology 1991;19:199-209.

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Cystic nephroma: cytologic findings in fine-needle aspiration cytology.

This report presents the fine-needle aspiration cytology (FNAC) findings of a multicystic renal tumor found in a 3-year-old child. The smears containe...
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