2

Click here to load reader

Primary primitive neuroectodermal tumor (PNET) of the kidney with venous thrombus

Embed Size (px)

Citation preview

Page 1: Primary primitive neuroectodermal tumor (PNET) of the kidney with venous thrombus

International Urology and Nephrology 35: 311–312, 2003.© 2004 Kluwer Academic Publishers. Printed in the Netherlands.

311

Primary primitive neuroectodermal tumor (PNET) of the kidney withvenous thrombus

B. Sivaramakrishna1, Om Prakash Mundada1, Monish Aron1, Manju Aron2 &M. Vijayaraghavan2

1Department of Urology, All India Institute of Medical Sciences, New Delhi 110 029, India; 2Department ofPathology, All India Institute of Medical Sciences, New Delhi 110 029, India

Abstract. Primitive neuroectodermal tumors of the kidney are rare, the diagnosis usually being made athistopathology. A young adult presented with a painful left renal mass. CT Scan of the abdomen revealed a largenecrotic tumor of the left kidney. At surgery the patient was found to have a venous thrombus confined to the renalvein. Radical nephrectomy was done. Histopathology showed a round cell neoplasm with typical Homer Wrightrosette formation and positive staining for neuron specific enolase (NSE) and MIC-2 on immunohistochemistry.The patient is undergoing multidrug chemotherapy and is alive and well at a follow up of nine months.

Key words: Kidney, Neuroectodermal, Primitive, PNET, Tumor, Venous thrombus

Introduction

Primary primitive neuroectodermal tumors of thekidney are extraordinarily rare tumors of the kidney[1]. They usually affect young individuals, are large atpresentation and tend to be highly aggressive tumors.A multimodality approach is needed to treat them butlong-term survival remains poor [2]. We report onesuch case with a renal vein thrombus.

Case report

A 27-year-old male presented with pain and fullnessof the left flank of 2 months duration. On examinationhe had a hard non-tender left renal lump 15 × 10 cmin size. Routine laboratory parameters were withinnormal limits. A CECT of the abdomen (Figure 1),revealed a large 16 × 11 cm heterogenous mass withmultiple areas of necrosis involving the upper pole ofthe left kidney with no significant adenopathy. Therenal vein and IVC were reported as normal.

The patient was taken up for surgery where it wasfound he had a tumor thrombus confined to the renalvein. A radical nephrectomy was done; ligating theleft renal vein flush on the IVC, clear of the thrombus.Postoperative recovery was uneventful.

Figure 1. Computed tomogram (CT) showing a large left kidneymass with areas of necrosis.

Microscopically the tumor was composed of smallround cells with scanty cytoplasm and vesicular nuclei(Figure 2). The tumor cells were present in groupsseparated by fibrovascular septae. Homer Wrightrosette formation was seen, with mitotic figures 1/10per HPF. Large areas of necrosis were seen with tumorinvading the capsule and perinephric fat. Immuno-histochemically the tumor cells were positive for

Page 2: Primary primitive neuroectodermal tumor (PNET) of the kidney with venous thrombus

312

Figure 2. Histology slide (H&E X100) showing a tumor composedof round cells with scanty cytoplasm and large hyperchromaticnuclei.

MIC-2 and NSE, suggesting a diagnosis of primitiveneuroectodermal tumor.

He was started on adjuvant chemotherapy ofVincristine, Adriamycin, Cyclophosphamide, Ifosfa-mide and Etoposide (4 cycles) followed by Vincristine,Adriamycin and Cyclophosphamide weekly for 48weeks. The patient is presently alive and disease freeat nine months follow-up, undergoing chemotherapy.

Discussion

Primitive neuroectodermal tumors were first describedby Stout [3], in association with peripheral nerves.Children and adolescents are the most frequentlyafflicted. The most common locations are in the softtissue of the trunk, head and neck and extremities.Primary PNET of the kidney is very rare and to ourknowledge, this is the fourth case of primary PNETof the kidney with a venous thrombus being reported,earlier reports being tumors with a level II (infra-hepatic IVC) [4] and level IV (supra-diaphragmaticIVC) [2] thrombus and a level II thrombus withpulmonary metastases [5].

PNET of the kidney afflicts the relatively young.The tumors are usually large at presentation andhighly aggressive in nature. In a recent analysis of 11cases [1], the mean age at presentation was 34 years.The mean tumor size was 11.8 +/– 3.8 cm. Common

symptoms were flank pain and/or haematuria. Grosslyall tumors showed necrosis and hemorrhage. At amean follow up of 28 months there were 4 lung andpleural metastases, 2 local recurrences and 1 bone andliver metastases. There were 5 deaths, median time todeath being 16.8 months.

Histologically PNET is characterized by smallround cells that may form Homer Wright rosettes orpseudo rosettes. Though the diagnosis can usuallybe made by light microscopy, immunohistochemicaltechniques may be required to differentiate PNETfrom other small round cell tumors like monophasicWilm’s tumor, neuroblastoma, clear cell sarcomaof the kidney and primitive rhabdomyosarcoma.Positive antibody staining for MIC-2 helps confirm thediagnosis [6].

Considering the rarity of the tumor, there is nostandard treatment protocol. Most authors recommendsurgery followed by multi drug chemotherapy as wehave followed. We suggest that PNET of the kidneyshould be kept in mind as a differential diagnosis inyoung adults presenting with a large kidney mass thatshows evidence of necrosis on imaging.

References

1. Jimenez RE, Folpe AL, Lapham RL et al. Primary Ewing’ssarcoma/primitive neuroectodermal tumor of the kidney: Aclinicopathologic and immunohistochemical analysis of 11cases. Am J Surg Pathol 2002; 26(3): 320–327.

2. Thomas JC, Sebek BA, Krishnamurthi V. Primitive neuroecto-dermal tumor of the kidney with inferior vena cava and atrialtumor thrombus. J Urol 2002; 168: 1486–1487.

3. Stout AP. A tumor of the ulnar nerve. Proc NY Pathol Soc 1918;12: 2–12.

4. Karnes RJ, Gettman MT, Anderson PM et al. Primitive neur-oectodermal tumor (extra skeletal Ewing’s sarcoma) of thekidney with vena caval thrombus. J Urol 2000; 164: 772.

5. Wada Y, Yamaguchi T, Kuwahara T et al. Primitive neuroecto-dermal tumor of the kidney with spontaneous regression ofpulmonary metastases after nephrectomy. Br J Urol 2003; 91:121–122.

6. Ambros IM, Ambros PF, Strehl S et al. MIC-2 is a specificmarker for Ewing’s sarcoma and peripheral primitive neuro-ectodermal tumors. Cancer 1991; 67: 1886–1893.

Address for correspondence: Dr Monish Aron, Assistant Professor,Department of Urology, All India Institute of Medical Sciences,New Delhi 110 029, IndiaPhone: +91-11-26594884; Fax: +91-11-26588663E-mail: [email protected]