Diseases of infancy and childhood III

Question 1

what is multiple myofibromas?

Answer 1

benign fibrous tumor in which the cells express muscle-specific actin

Question 2

what is the most common fibrous tumor in infants?

Answer 2

multiple myofibromas

Question 3

what is infantile fibromatosis?

Answer 3

myofibroblasts infiltrate skeletal muscle - benign tumor consisting of fibroblasts and myofibroblasts (does not metastasize)

Question 4

what is the histologic appearance of fibrosarcoma?

Answer 4

high grade atypia, high mitotic index, abnormal mitotic figures, hyperchromic nuclei

Question 5

what is the most common solid tumor in newborns?

Answer 5

sacrococcygeal teratomas

Question 6

what is the most common solid congenital malignancy

Answer 6

congenital neuroblastoma

Question 7

what percent of teratomas are malignant?

Answer 7

12% of teratomas with immature tissue microscopically

Question 8

what is the origin of neuroblastomas?

Answer 8

malignant tumor of primitive sympathetic cells found in adrenal medulla and sympathetic ganglia

Question 9

what are the most common clinical findings of neuroblastoma?

Answer 9

weight loss, abdominal mass, “blueberry muffin baby”

Question 10

what is the blood diagnosis for neuroblastoma? urine? bone marrow?

Answer 10

1. blood - increased catecholamines, NSE 2. urine - increased catecholamine metabolites, VMA, HVA 3. bone marrow - NSE staining by IHC

Question 11

what is the histologic appearance of neuroblastoma at the light microscopy level?

Answer 11

small round pleomorphic blue cells in a rosette structure

Question 12

what is the histologic appearance of neuroblastoma at the electron microscopy level?

Answer 12

dense core neurosecretory granules are observed

Question 13

what is the most common primary malignant tumor of kidney in children?

Answer 13

Wilms tumor

Question 14

what are the clinical findings of Wilms tumor?

Answer 14

abdominal mass, hematuria, fever, hypertension

Question 15

what is the histologic appearance of Wilms tumor?

Answer 15

tightly packed blue cells consistent with blastemal component and interspersed primitive tubules representing the epithelial component

Question 16

what congenital malformations are associated with Wilms tumor?

Answer 16

WAGR syndrome and Denys-Drash syndrome

Question 17

what are the features of WAGR syndrome?

Answer 17

33% risk for WT, aniridia, genital anomalies, mental retardation

Question 18

what are the features of Denys-Drash syndrome?

Answer 18

90% risk for WT, nephropathy, gonadal dysgenesis,

Question 19

what is the most common sarcoma of childhood?

Answer 19

rhabdomyosarcoma

Question 20

what are the three subtypes of rhabdomyosarcoma? what are their prevalences?

Answer 20

1. embryonal rhabdomyosarcoma - 60% (best prognosis) 2. alveolar rhabdomyosarcoma - 20% 3. pleomorphic rhabdomyosarcoma - 20% (worst prognosis)

Question 21

what is the histologic appearance of embryonal RMS?

Answer 21

malignant cells ranging from primitive and round to spindled eosinophilic cell (skeletal muscle differentiation)

Question 22

what is the histologic appearance of alveolar RMS?

Answer 22

1. tumor is traversed by a network of fibrous septae that divide the cells into clusters or aggregates - crude resemblance to alveoli 2. tumor cells are uniform and round with little cytoplasm

Question 23

what is the histologic appearance of pleomorphic RMS?

Answer 23

numerous large, sometimes multinucleated, bizarre eosinophilic tumor cells staining for myogenin by IHC

Question 24

what is the prenatal screening test for NTDs?

Answer 24

maternal serum AFP