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jaf

A 2-year-old child is seen for a welI-child visit in a pediatric clinic. Abdominal examination demonstrates a palpable, non-tender mass on the Ieft side of the abdomen. The mother had no idea the mass was present and the pediatrician did not note the presence of the mass at the child's 18-month welI-child visit. Physical examination is otherwise unremarkable.

Question 1 of 4
CT examination demonstrates an 8-cm diameter, roughly round, mass involving the lower pole of the kidney. Which of the following is the most likely cause of this mass?
A. Ewing sarcoma
B. Neuroblastoma
C. Renal cell carcinoma
D. Transitional cell carcinoma
E. Wilms tumor

Question 2 of 4
If a CT guided biopsy of the mass were performed, which of the following histological patterns would be most suggestive of the likely diagnosis?
A. Cords of clear cells with rounded or polygonal shape and abundant clear cytoplasm
B. Invasive papillary lesions with delicate connective tissue stalk covered with epithelium resembling that lining the bladder
C. Small dark cells embedded in a finely fibrillar matrix with formation of numerous rosettes
D. Triphasic pattern with tubule formation, spindle cells, and blastemal elements
E. Uniform sheets of small round cells with scanty cytoplasm

Question 3 of 4
Sometimes this child's disease occurs in association with certain congenital anomalies. Children with which of the following abnormalities at birth should be monitored for the development of this disease?
A. Aniridia
B. Coarctation of the aorta
C. Cystic hygroma
D. Parathyroid hyperplasia
E. Simian crease

Question 4 of 4
Abnormalities of which of the following chromosomes have been linked to this disease?
A. 3
B. 5
C. 11
D. 15
E. 21

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jaf

1 of 4
The correct answer is E.
Wilms tumor is an embryonal malignancy of the kidney that most commonly affects children from birth to age 4, but can affect children up to about age 15. This tumor is the second most common extracranial solid tumor in children and tends to form large, round, solitary masses of the kidney, although bilaterality and multicentricity may also occur. Wilms tumors usually present with a palpable abdominal mass, with less common presentations including abdominal pain, hematuria (indicating invasion of the collecting system), hypertension, fever, nausea, and vomiting.

2 of 4
The correct answer is D.
Adequate sampling of most Wilms tumors will detect the three distinct growth patterns that are most characteristic of this tumor: less cellular tumor areas containing spindle cells; densely cellular (blastemal) areas with closely packed small cells with scanty cytoplasm and darkly blue nuclei; and areas with production of more mature-appearing epithelium that may form occasional tubules. The tissues present are similar to those present in the developing kidney, and may also include primitive glomeruli. Wilms tumors may additionally contain heterologous elements, such as skeletal muscle, smooth muscle, squamous or mucinous epithelium, adipose tissue, cartilage, bone, or neural tissue.

3 of 4
The correct answer is A.
The WAGR syndrome includes Wilms tumor, aniridia (lack or defect of the iris), genital anomalies (gonadal dysgenesis, hypospadias, cryptorchidism, or other genitourinary anomalies), and mental retardation. Wilms tumor can also occur as part of the Beckwith-Wiedemann syndrome with hemihypertrophy, and the Drash syndrome with nephropathy and ambiguous genitalia.

4 of 4
The correct answer is C.
Inactivation of the WT-1 Wilms tumor gene (located at 11p13, and thought to encode a DNA-binding protein important in fetal kidney development) has been reported in the tumor cells from many Wilms tumor cases. Also, the WAGR syndrome involves a deletion of chromosome 11p13 and the Beckwith-Wiedemann syndrome involves a rearrangement of chromosome 11p15. The genetic basis of the Drash syndrome has not been established. The other choices are distracters.