| 31 [19-1a]: Pediatric Pathology 1. Congenital Cytomegalovirus History- This male infant was noted by ultrasound to have an enlarged abdomen at 24 weeks gestation. The 22- year-old mother gave a history of a brief febrile illness during her first few weeks of pregnancy. The infant was born by spontaneous vaginal delivery at 35 weeks gestation. The infant died shortly after birth of respiratory distress. A. At birth the infant was noted to have an enlarged abdomen with a prominent fluid wave that extended into his enlarged scrotum. Note the numerous petechiae (small hemorrhages) over the trunk, face and limbs. [19-1b]:1B. The abdomen was filled with clear yellow fluid that distended the abdomen, elevating the diaphragms and compressing the developing lungs. The liver was only mildly enlarged. [19-1c]:1C. The liver architecture is distorted by prominent lymphoid aggregates in and adjacent to portal areas. Bile ducts are lined by normal appearing or occasional enlarged epithelial cells. [19-1d]:1D. The enlarged bile duct epithelial cells are 3- 4X the size of the normal cells and contain an enlarged nucleus with a prominent eosinophilic inclusion surrounded by a clear "halo". These cells are pathognomonic of cytomegalovirus infection. [19-1e]:1E. The brain was mildly hydrocephalic with dilated ventricles and a thinned cerebral cortex. Upon sectioning the brain a coarseness was felt in the periventricular region representing areas of calcification. Questions 1. What is the incidence of CMV infection during pregnancy and how many infants will be mildly or severely infected? 2. What are the clinical manifestations of congenital CMV infection? 3. What other organisms are associated with congenital infections? [19-2a]:2. Congenital Group B Streptococcal Infection History- This term male infant was born 28 hours after premature rupture of the amniotic membranes. He was in mild respiratory distress at birth which progressed rapidly to death at 8 hours of age. A. The lungs at autopsy were consolidated and unevenly expanded. [19-2b]:2B. Bronchi, bronchioles and alveolar ducts are filled with acute inflammatory cells (neutrophils). [19-2c]:2C. Alveoli are distended by neutrophils and macrophages along with thin linear eosinophilic structures representing aspirated squamous cells (squames) that are sloughed from the infant's skin after about 25 weeks gestation. Note the faintly basophilic granular material in the alveolus representing clusters of bacteria. [19-2d]:2D. A section from the placenta of this infant displays marked subchorionic inflammation that extends through the chorion into the amnion (acute chorioamnionitis). Questions- 1. What are the routes through which an infant may become infected inutero? 2. How does Group B Streptococcal infection differ from a TORCH infection? 3. Describe the stages or degrees of infection of the placenta? [19-3a]:3. Potter Syndrome History- This term male infant was born to a mother who had been noted to have oligohydramnios throughout the third trimester. The infant experienced severe respiratory distress and died minutes after birth. A. Note the 'cramped' position of the infant with the arms folded across the chest (compressing the thorax) and the legs bent across the abdomen (twisting the feet). [19-3b]:3B. From the side, the typical features of Potter's Facies can be seen including a sloping forehead, flattened nose, recessed chin and lowset floppy ears (elephant-like). [19-3c]:3C. The opened thorax shows a narrow thoracic cavity occupied mainly by the heart, allowing little room for the development of the lungs. [19-3d]:3D. The lungs, while appearing normal in configuration, weigh only 22 grams vs an expected weight of 54 grams for a term infant. [19-3e]:3E. A section from the periphery of the lungs shows a terminal bronchiole just beneath the pleura. A radial alveolar count (RAC) is made by extending a perpendicular line from the center of the bronchiole to the pleura and counting the number of alveolar septa crossed. In a term infant this number is usually 5 or 6 compared to 2 or 3 in this infant. This decreased RAC is indicative of pulmonary hypoplasia. [19-3f]:3F. With the bowel distal to the stomach removed from the abdomen, the vertebral column and adjacent psoas muscles are easily seen. The kidneys, however, are absent, although the adrenals can be seen near the top of the psoas muscles on either side. [19-3g]:G. The surface of the placenta is studded with small white nodules (amnion nodosum) representing collections of amniotic cells stuck to the surface, a frequent finding in cases of oligohydramnios. [19-3h]:H. While the kidneys in this Potter's Syndrome infant are present, they are markedly dilated and filled with fluid. This congenital hydronephrosis was secondary to an atresia of the urethra. Potter's Syndrome Questions- 1. What is the mechanism of development (i.e., the etiology) of Potter's Syndrome? 2. What are the major features of Potter's Syndrome? 3. What renal anomalies are associated with the development of Potters Syndrome? 4. What are some other causes of pulmonary hypoplasia? [19-4a]:4. Wilms' Tumor - Nephroblastoma History- This five year old boy was noted by his pediatrician on routine physical exam to have a mass in the right lower quadrant of his abdomen. A CT scan displayed a mass virtually replacing the right kidney. The left kidney was unremarkable. The mass was resected. A. The mass is composed of encapsulated pale tan, lobulated tissue subdivided by irregular fibrous septa. Note the thin rim of normal kidney at upper right. [19-4b]:4B. The tumor consist of sheets and clusters of 'small round blue cells' separated by bands of fibrous connective tissue. Note the duct-like structures within the 'blastemal' cell clusters. [19-4c]:4C. In some areas the entire tumor is composed of tubular structures . [19-4d]:4D. In other areas mesenchymal components resembling immature fibroblasts predominate. [19-4e]:4E. Within the blastemal area clusters of large, hyperchromatic cells with bizarre mitoses (anaplasia) may be present. [19-4f]:4F. Spread of tumor may be seen along veins in the renal hilus. Questions 1. What are the anomalies and syndromes associated with Wilms' tumor? 2. What are the tissue patterns or cells types noted in Wilms' tumor? 3. What are the good and bad prognostic indicators of Wilms' tumor? [19-5a]:5. Rhabdomyosarcoma History- This 9 year old male complained of constipation, and on physical examination was note to have a large retroperitoneal mass that compressed the rectum. The mass was excised. A. The mass is poorly encapsulated and composed of irregular nodules of tan-white tissue. [19-5b]:5B. On cut section the mass consists of soft, tan tissue subdivided by fibrous septa. [19-5c]:5C. In the embryonal form of rhabdomyosarcoma, the tumor is composed of sheets of round to tapered cells in a rich vascular stroma. [19-5d]:5D. In this embryonal rhabdomyosarcoma, note the elongate cells with 'tails' of granular cytoplasm (strap cells) and plump cells with abundant cytoplasm (rhabdomyoblasts). Cross striations may occasionally be seen in these cells. [19-5e]:5E. The alveolar pattern of rhabdomyosarcoma consists of fibrous septa lined by or covered with 'small round blue cells' that may fill the intervening spaces. [19-5f]:5F. The individual cells of the alveolar form may have eccentric collections of eosinophilic cytoplasm (rhabdomyoblasts). [19-5g]:5G. When arising in a hollow structure (bladder, vagina, bile duct) a rhabdomyosarcoma forms 'grape-like' structures and is referred to as botryoid ( a gross description only). [19-5h]:5H. In a botryoid rhabdomyosarcoma, the embryonal pattern consists of a dense collection of rhabdomyoblasts beneath the normal epithelium of the structure involved. Deeper to the epithelium, the cells are less dense and strap cells with cross striations may be present. Questions- 1. What are the most common sites of involvement of rhabdomyosarcoma in children? 2. What are the two basic tissue patterns of rhabdomyosarcoma in children? 3. What factors influence the prognosis of rhabdomyosarcoma? | |
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