TA OGUNLESI (FWACP)1 NEPHROBLASTOMA (WILM’S TUMOR)
TA OGUNLESI (FWACP)2 EPIDEMIOLOGY WT is a tumor of the developing kidney WT is the most common renal tumor in children. Incidence is approximately 0.8 cases per 100,000 persons in the US. WT formed 15% of all childhood cancers in Enugu (1999 – 2004)
TA OGUNLESI (FWACP)3 EPIDEMIOLOGY Peak age at diagnosis is between 3yrs and 4 years Mean age at diagnosis is 3.5years Most cases (80%) are diagnosed before 5yrs of age No sex predilection Most cases are SPORADIC (not related to any hereditary or genetic tendency) Only about 2.5% is familial
TA OGUNLESI (FWACP)4 AETIOLOGY The clinical settings include: Sporadic Familial Associated with genetic syndromes (12-15%) The familial type is associated with genito-urinary abnormalities like hypospadias, cryptorchidism, ureteral duplication, polycystic kidneys The genetic syndromes that may be associated with WT: Beckwith-Wiedemann syndrome Unilateral hemihypertrophy Aniridia
TA OGUNLESI (FWACP)5 PATHOPHYSIOLOGY The aetiology is unknown. The pathophysiology is characterized by an abnormal proliferation of the metanephric blastema. Histology shows 3 components: primitive metanephric blastema, dysplatic tubules and the mesenchyme The degree of differentiation of each component determines whether the tumour has favourable or unfavourable histology.
TA OGUNLESI (FWACP)6 PATHOPHYSIOLOGY WT can arise anywhere within the kidney It distorts the renal architecture unlike Neuroblastoma which only displaces the kidneys downward without distorting its architecture Spreads beyond a tumor capsule into the renal sinus, intra-renal lymphatics and blood vessels → metastases (commonly to the lungs & liver) Vigorous abdominal palpation spills the cells into the abdominal cavity and encourages dissemination
TA OGUNLESI (FWACP)7 CLINICAL FEATURES Asymptomatic flank mass is the most common feature (Crosses the midline in 10% of cases) Others include: Abdominal pain in 30-40% of cases. Gross haematuria in 5-10% of cases. Constipation from pressure effect.
TA OGUNLESI (FWACP)8 CLINICAL FEATURES Severe anaemia with fatigue (secondary to haematuria) Mild-to-moderate hypertension in 10% of cases. Fever from tumour necrosis Cough & dyspnea from pulmonary metastases.
TA OGUNLESI (FWACP)9 INVESTIGATIONS Ultrasound – initial screening tool Computed tomography scan –Differential diagnosis of a kidney tumor versus adrenal tumor (neuroblastoma) –Liver metastases Chest x-ray - As a baseline for pulmonary metastases Magnetic resonance imaging Biopsy should be avoided to prevent spillage
TA OGUNLESI (FWACP)10 CLINICAL STAGING Stage I: The tumor is limited to the kidney and is excised completely. Stage II: The tumor extends beyond the kidney into peri-renal tissue but is excised completely. Stage III: Residual intra-abdominal tumor (nonhematogenous) exists after surgical resection.
TA OGUNLESI (FWACP)11 CLINICAL STAGING Stage IV: Hematogenous or lymph node metastasis has occurred outside the abdomen or pelvis. Stage V: Synchronous bilateral involvement has occurred. Each side is assigned a stage from I to III
TA OGUNLESI (FWACP)12 MANAGEMNET It is a potentially curable tumor. Surgical therapy: The first step is surgical staging followed by radical nephrectomy, if possible. If the tumor is unresectable, biopsies are performed and the nephrectomy is deferred until after chemotherapy, which will shrinks the tumor in most cases.
TA OGUNLESI (FWACP)13 MANAGEMENT Adjuvant chemotherapy has improved disease-free survival. The cytotoxic agents are Vincristine, Actinomycin-D and Adriamycin Radiotherapy is only useful if there is residual bulk disease after surgery.
TA OGUNLESI (FWACP)14 PROGNOSIS With the advent of multimodal therapy, the prognosis is good. The overall cure rate approaches %. Cases with diffuse anaplasia and stage III or IV that recur in spite of the complex therapy have a bad prognosis.