A Case of Primitive Neuro Ectodermal Tumour

Introduction

Primitive neuro ectodermal tumours were first described in 1918.1 Because of recent immuno histological studies, the number of neuroectodermal tumours being reported have increased. We report a case of PNET and the need for polychemotherapy and high dose chemotherapy to manage the case.

Case Report

34 year old male presented with history of fall and unconsciousness. On admission he was detected to have hypertension and abdominal ultrasonography showed a right renal mass. Retrospectively, when asked, the patient had vague right abdominal pain but gave no history of haematuria, renal lump, fever, jaundice or haemoptysis.

CT scan revealed a right upper polar mass 15 cm x 10 cm with IVC thrombus up to the sub hepatic veins, with wall invasion and 2 cm hyper-echoic mass in the right lobe of liver. Patient underwent radical nephrectomy with IVC thrombectomy.

A diagnosis of PNET was established and 4 cycles of Vincristine, Ifosfamide and Etoposide were given. After the first cycle, the patient had myelotoxicity, thrombocytopenia and the 2nd chemotherapy schedule was changed to Vincristine and Cyclophosphamide only, which was started 4 months later. Bone scan done then showed metastases in the sternum and left temporal lesion. The third schedule was given with cyclophosphamide and vincristine only and the 4th schedule could be completed with vincristine, Ifosamide and Etoposide.

Radiotherapy 4860 cGy was given in 27 fractions to the bone metastasis and upper abdomen. The patient is in remission after a follow up of 2 yrs.

Discussion

Primitive neuro ectodermal tumours are neoplasms arising from neuro ectodermal, round cells with cholinergic features, commonly seen in soft tissues of the trunk head, neck and extremities. Kidney is rarely involved by PNET and till date only 23 cases have been reported.²


	Fig. 1 : CT scan abdomen showing tumour with IVC thrombus.

	Fig. 2 : HPE (high power resolution) showing rosette formation in PNET.

The diagnosis of PNET is usually not possible pre-operatively from the clinical or radiological features but should be suspected in young patients with advanced presentation.¹

The pathological differential diagnosis of malignant small round cell tumours of kidney are monophasic Wilm’s tumours, carcinoid, clear cell sarcoma of kidney, primitive rhabdomyosarcoma, neuroblastoma, lymphoma and small cell variant of osteo-sarcoma.²

Differentiation of PNET from other variants of round cell tumours is by immunohistological techniques.

Once the diagnosis is established, the prognosis of the patient depends upon the staging, age of patient, extent of surgical resection and time to treatment. PNET is an aggressive tumour which tends to recur locally and metastasize to regional nodes, lungs, liver and bone. They are relatively sensitive to chemotherapy and radiotherapy. A combination of doxorubicin and cyclophosphamide for 4-6 cycles, along with radical debulking surgery and radiotherapy leads to remission or at least dramatic tumour reduction. Other agents known to be effective are Ifosamide, etoposide, teniposide and cisplatin. As there are very few cases sporadically reported from various centres there are no definite chemotherapy regimens or randomized studies.³

High dose chemotherapy with stem cell rescue is done in few cases patients with metastasis usually relapse after 2 years.⁴

Conclusions

PNET of the kidney is a rare tumour with few cases in world literature. Diagnosis of PNET should be suspected in young patients with advanced or metastatic disease. Polychemotherapy and high dose chemotherapy with stem cell autotransplant and radiotherapy, as an adjuvant to debulking surgery is the mode of therapy, leading to tumour reduction or remission.

References

1. Stout AP. A tumour of the ulnar nerve. Proc NY Pathol Soc 1918; 18 : 2-12.

2. Mor Y, Nass D, Raviv G, Neumann Y, et al. Malignant peripheral primitive neuroectodermal tumour of the kidney. Med Peditr Oncol 1994; 23 : 437-40.

3. Isreal M, Miser J, Triche TJ. Neuroepithelial tumours in Pizz PA, PoplackDg (ed) : Pediatric Oncology, Philadelphia, Lippincott 1989; 29 : 923-34.

GOUT : A DRINKERS’ DISORDER?

‘Alcohol intake is strongly associated with an increased risk of gout’.

The association between heavy alcohol consumption and increased risk of gout has long been suspected, but has not been prospectively confirmed. Hyon Choi and co-workers used biennial questionnaires to assess the relation between alcohol consumption and type of alcoholic beverage and risk of incident gout. They found a strong association between alcohol consumption and gout, and that the risk increased substantially according to type of alcohol beverage. Qing Yu Zeng suggests that more research is needed on the significance of factors other than alcohol intake in gout, such as differing dietary composition.

Lancet, 2004; 5 : 1277, 1251.