Ans. C. Abdominal mass. (Ref. Robin's Pathology 8th/pg. 271; Love and Bailey 26th/pg.l24; 1304).Nephroblastoma (Wilms' tumour)# Usually presents in the first five years of life# Typically presents with an abdominal mass# May cause haematuria, abdominal pain or fever# It extends into the renal vein and vena cava and metastasises to lymph nodes and lungs.# Treatment is with chemotherapy and surgery.Wilms' tumour (nephroblastoma) is a malignant renal tumour derived from embryonal cells; it typically affects children aged from 1 to 4 years. A mutation in the Wilms' tumour suppressor gene (WT1) is responsible for some cases. It usually presents as an abdominal mass. The tumour extends into the renal vein and vena cava and metastasises to lymph nodes and lungs. Treatment is with chemotherapy and surgery. Survival depends on tumour spread, completeness of surgical excision and histology but exceeds 70% even among patients with advanced tumours.Wilms' Tumor (nephroblastoma)# Most common primary tumor of the kidney in children.# malignant renal tumour derived from embryonal cells; it typically affects children aged from one to four years. Following are associated with an increased risk of developing Wilms' tumor:- WAGR syndrome: aniridia, genital abnormalities, and mental retardation, have a 33% chance of developing Wilms' tumor.- Denys-Drash syndrome (DDS):extremely high risk (?90%) of developing Wilms' tumor. Characterized by gonadal dysgenesis and renal abnormalities.- Beckwith-Wiedemann syndrome (BWS): enlargement of individual body organs (e.g., tongue, kidneys, or liver) or entire body segments (hemihypertrophy); enlargement of adrenal cortical cells (adrenal cytomegaly) is a characteristic microscopic feature. BWS is an example of a disorder of genomic imprinting. The genetic locus that is involved in these patients is in band pi5.5 of chromosome 11 distal to the WT1 locus.- Microscopically, Wilms' tumors are characterized by recognizable attempts to recapitulate different stages of nephrogenesis. The classic triphasic combination of blastemal, stromal, and epithelial cell types is observed in most lesions. Sheets of small blue cells, with few distinctive features, characterize the blastemal component.- Nephrogenic rests are putative precursor lesions of Wilms' tumors.- The prognosis for Wilms' tumor is generally very good, and excellent results are obtained with a combination of nephrectomy and chemotherapy.- Anaplasia is a harbinger of adverse prognosis, but careful analyses by the National Wilms' Timor Study group in the United States have shown that as long as the anaplasia is focal and confined within the resected nephrectomy specimen, the outcome is no different from tumors without evidence of anaplasia. In contrast, Wilms' tumor with diffuse anaplasia the prognosis is poor.Additional Educational points:Neuroblastoma is a malignancy of neuroblasts in the adrenal medulla or sympathetic ganglia and typically presents as an abdominal or paravertebral mass. It metastasises to lymph nodes, bones and liver and causes elevated urinary catechola- mines. Small-localised tumours are excised. More advanced tumours are treated by chemotherapy and surgery. Survival is related to tumour biology and stage (>90% for small localised tumours, < 50% for advanced tumours).Neuroblastoma is the most common abdominal tumor of infancy. It is much less common than the relatively common hydronephrosis. The most common abdominal mass in a newborn infant is hydronephrosis. It is a common finding in prenatal ultrasounds. It will usually resolve without therapy. Hepatomas and Wilms tumors are even rarer than neuroblastoma.