PRIMITIVE NEUROECTODERMAL TUMOR OF THE KIDNEY WITHINFERIOR VENA CAVA AND ATRIAL TUMOR THROMBUS

JOHN C. THOMAS, BRUCE A. SEBEK AND VENKATESH KRISHNAMURTHIFrom the Urological Institute and Department of Anatomic Pathology, Cleveland Clinic Foundation, Cleveland, Ohio

KEY WORDS: neuroectodermal tumors, primitive; sarcoma, Ewing’s; thrombosis; kidney

Primitive neuroectodermal tumor of the kidney is a raremalignancy. We report a case of renal primitive neuroecto-dermal tumor with a level IV inferior vena caval thrombusthat was managed successfully with deep hypothermic circu-latory arrest.

CASE REPORT

A 55-year-old woman presented with vague left lowerquadrant discomfort. Physical examination and laboratorytests were unremarkable. Computerized tomography (CT) ofthe abdomen and pelvis revealed a 5.7 � 4.7 cm. heteroge-neously enhancing right renal mass with thrombus noted inthe right renal vein extending superiorly to the level of theright atrium (fig. 1). Transesophageal echocardiography con-firmed a large right atrial thrombus. Chest CT showed a 2.5cm. left lower lobe mass, which on biopsy demonstrated be-nign fibro-connective tissue.

The patient underwent right radical nephrectomy andlevel IV inferior vena caval thrombectomy with cardiopulmo-nary bypass and deep hypothermic circulatory arrest. Grossexamination revealed a firm 5.2 cm. mass in the right kidney.Microscopically there were sheets and lobules of cells withround to oval nuclei and coarse chromatin, as well as HomerWright rosette formation. Immunohistochemical analysisshowed strongly positive staining for CD99 (fig. 2) and neg-ative staining for other neuroendocrine markers such as syn-aptophysin and chromogranin. No molecular analysis wasperformed on the specimen.

Presently the patient remains disease-free at limited fol-lowup 5 months postoperatively. Repeat CT of the chest,abdomen and pelvis before starting chemotherapy was neg-ative for metastatic disease, and the previously noted chestlesion was found to be unchanged in size. The patient has

completed 2 cycles of ifosfamide, cyclophosphamide and doxo-rubicin, and has tolerated the chemotherapy well withoutsignificant side effects.

DISCUSSION

Primary primitive neuroectodermal tumors arising fromthe kidney are rare. To our knowledge only 1 renal primitiveneuroectodermal tumor with a level II thrombus has beenreported in the literature.1 Thus, we report the first primitiveneuroectodermal tumor of the kidney with a level IV throm-bus, which was managed with deep hypothermic circulatoryarrest.Accepted for publication May 3, 2002.

FIG. 1. CT demonstrates heterogeneously enhancing right renal mass with extension into inferior vena cava and right atrium

FIG. 2. Renal primitive neuroectodermal tumor is composed ofsheets of cells with round and oval nuclei that stain positive forCD99.

0022-5347/02/1684-1486/0 Vol. 168, 1486–1487, October 2002THE JOURNAL OF UROLOGY® Printed in U.S.A.Copyright © 2002 by AMERICAN UROLOGICAL ASSOCIATION, INC.® DOI: 10.1097/01.ju.0000023439.32024.78

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These tumors typically manifest in children and youngadults. In a review by Kuroda et al average age at diagnosis was27.7 years.2 Primitive neuroectodermal tumor and Ewing’s sar-coma share the (11:22)(q24:q12) chromosomal translocation, aunique genomic marker found in tumors of the Ewing’s sarcomafamily. Using reverse transcriptase-polymerase chain reaction,one can also demonstrate the EWS-FLI1 chimeric gene, ahighly specific molecular marker.3

Histologically primitive neuroectodermal tumor is charac-terized by small round cells that may form Homer Wrightrosettes or pseudo-rosettes. By using immunohistochemicaltechniques, primitive neuroectodermal tumor can be differ-entiated from other small round cell tumors, includingmonophasic Wilms tumor, neuroblastoma, clear cell sarcomaof the kidney and primitive rhabdomyosarcoma.3 Antibodystaining for the MIC2 gene product, CD99, frequently helpsconfirm the diagnosis.

Despite attempts at combined therapy, including surgery,

chemotherapy and radiotherapy, prognosis remains poor inmost cases with a reported 5-year survival rate of 45% to55%.3 Given the highly aggressive nature of this tumor,adjuvant multidrug chemotherapy is encouraged by mostauthors. Although rare, primitive neuroectodermal tumor ofthe kidney should be considered in adults presenting with arenal mass and inferior vena caval tumor thrombus.

REFERENCES

1. Karnes, R. J., Gettman, M. T., Anderson, P. M., Lager, D. J. andBlute, M. L.: Primitive neuroectodermal tumor (extraskeletalEwing’s sarcoma) of the kidney with vena caval tumor throm-bus. J Urol, 164: 772, 2000

2. Kuroda, M., Urano, M., Abe, M., Mizoguchi, Y., Horibe, Y.,Murakami, M. et al: Primary primitive neuroectodermal tu-mor of the kidney. Pathol Int, 50: 967, 2000

3. Casella, R., Moch, H., Rochlitz, C., Meier, V., Seifert, B.,Mihatsch, M. J. et al: Metastatic primitive neuroectodermaltumor of the kidney in adults. Eur Urol, 39: 613, 2001

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