136: Surgical Diseases of the Newborn: Retroperitoneal Tumors

NEUROBLASTOMA

I. DEFINITION

A neuroblastoma is a primitive malignant neoplasm that arises from neural crest tissue. Usually, it is located in the adrenal gland, but it can occur anywhere neural crest cells migrate. It is the most common extracranial solid malignancy of childhood. Incidence is ∼1 per 100,000 children in the United States.

II. CLINICAL PRESENTATION

This tumor typically presents as a firm, fixed, irregular mass extending obliquely from the costal margin, occasionally across the midline, and into the lower abdomen

III. DIAGNOSIS

1. Laboratory studies. A 24-hour urine collection should be analyzed for vanillylmandelic acid and other catecholamine metabolites. Elevated lactate dehydrogenase is associated with poor prognosis.

2. Imaging and other studies. A plain abdominal radiograph may reveal calcifications within the tumor. Computed tomography (CT) typically shows extrinsic compression and inferolateral displacement of the kidney. Metastatic evaluation involves bone marrow aspiration and biopsy, bone scan, chest radiograph, and chest CT.

IV. MANAGEMENT

Treatment is based on stage. Complete surgical resection remains the best hope for cure unless the infant has type 4S disease, which is associated with spontaneous regression. Planned therapy should take into account this well-recognized but poorly understood fact. Advanced tumors require multimodality therapy with surgery, radiation, and chemotherapy, but this is uncommon in neonates.

MESOBLASTIC NEPHROMA

I. DEFINITION

A mesoblastic nephroma is embryonic solid renal tissue that is not usually malignant.

II. CLINICAL PRESENTATION

A palpable mass is found on abdominal examination, or a solid kidney mass is seen on prenatal ultrasound

III. DIAGNOSIS

1. Physical examination. The mass is found on examination in the newborn period or becomes apparent in first few months of life.

2. Imaging and other studies. Ultrasonography is obtained when a solid mass is identified in the neonate

IV. MANAGEMENT

1. Surgery. Nephrectomy is indicated and includes lymph node sampling to assess for rare malignant degeneration.

WILMS TUMOR (NEPHROBLASTOMA)

I. DEFINITION

A Wilms tumor is an embryonal renal neoplasm in which blastemic, stromal, and epithelial cell types are present. Renal involvement is usually unilateral but may be bilateral (5% of cases).

II. CLINICAL PRESENTATION

A palpable abdominal mass extending from beneath the costal margin is the usual mode of presentation.

III. RISK FACTORS

Aniridia, hemihypertrophy, certain genitourinary anomalies, and a family history of nephroblastoma are well recognized

IV. DIAGNOSIS

1. Laboratory studies. No tumor marker is available.

2. Imaging and other studies. Ultrasonography is generally followed by CT, which reveals intrinsic distortion of the calyceal system of the involved kidney. The possibility ...