Practical electron microscopy of pediatric renal tumors.
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Child↗
Biomedical subjects
D A Weeks
Publications and source records attributed to D A Weeks.
Primary leiomyosarcoma of brain in an adolescent with common variable immunodeficiency syndrome.
A 14-year-old girl with common variable immunodeficiency syndrome was found to have a low-grade malignant neoplasm arising in the left temporal lobe of the brain. Ultrastructural and immunohistochemical studies established a diagnosis of leiomyosarcoma, despite the rarity of this tumor in children. In situ hybridization with the EBER probe revealed essentially all of the neoplastic cells to be infected with Epstein-Barr virus (EBV). Children with the acquired immunodeficiency syndrome (AIDS) are known to exhibit an increased incidence of smooth muscle tumors associated with EBV. Similar tumors have been reported in EBV-infected patients undergoing therapeutic immunosuppression. This appears to be the first reported case of childhood leiomyosarcoma where the cause of the underlying immunodeficiency was a genetic rather than acquired disorder. The authors conclude that electron microscopy, immunohistochemistry, and other ancillary techniques are essential in the evaluation of unusual tumors in immunocompromised children, whether the cause is hereditary or acquired.
Adolescent↗
Role of electron microscopy in the diagnosis of metabolic storage diseases affecting the nervous system of children.
Metabolic storage diseases are among the most challenging diagnostic problems faced by clinicians and pathologists. There is considerable variation in the diagnostic approach to these diseases between different institutions and between different diagnosticians. Much of this variation arises from differences in the availability of and physician confidence in the diagnostic modalities employed to characterize these disorders. Recent advances in the biochemistry and molecular genetics of these diseases have produced some skepticism about the continued relevance of traditional morphologic techniques, including electron microscopy, in their diagnosis. It is the opinion of the authors that this concern is premature and that electron microscopy continues to play a vital role, particularly in the diagnosis of those entities that challenge the classic definitions of lysosomal storage diseases. The authors present a series of cases illustrating different situations where electron microscopy can provide timely, cost-effective, and accurate information in the workup of such diseases.
Adolescent↗
Use of electron microscopy and other special techniques in the investigation of suspected specimen contamination.
Contamination of a biopsy or surgical specimen with spurious tissue is an uncommon but potentially disastrous event. In this regard, the case of a 5-year-old boy referred for treatment of an abdominal tumor is presented. Sections made from paraffin blocks brought by the family showed both neuroblastoma and a spindle cell sarcoma, initially suggesting the possibility of divergent or mixed differentiation. However, the resemblance of the spindle cell component to well-differentiated leiomyosarcoma rather than rhabdomyosarcoma raised the suspicion that a specimen contamination had occurred. Electron microscopy was instrumental in confirming the smooth muscle nature of the sarcomatous component, leading to a fluorescence in situ hybridization study, which established that this component was incompatible with the patient's gender. This case illustrates that even when the light microscopic differential has been compromised by specimen mishandling, electron microscopy can at times provide useful information regarding specimen identity, as well as assist in sorting out the correct diagnosis.
Actins↗
Patterns of measles pneumonitis.
As a result of the enlarging pool of unvaccinated children and young adults, there has been an increase in serious measles pneumonitis in our areas. We recently examined autopsy and/or lung biopsy material from five children with fatal measles pneumonitis. Two patients were immunocompromised because of either prematurity or acute leukemia and died 13-16 days following onset of symptoms. Both had classic giant cell pneumonitis, with readily demonstrable intranuclear inclusions. Three other children without known immunocompromise had a more prolonged course. The lungs of these patients lacked the classic pattern and displayed instead a spectrum of less specific findings ranging from organizing diffuse alveolar damage to interstitial pneumonia with giant cells, but without viral inclusions. An accompanying necrotizing bronchiolitis was also present. Electron microscopy and/or detection of elevated measles-specific immunoglobulin M was necessary to confirm the diagnosis in these apparently immunocompetent patients. We conclude that the histologic features of fatal or serious measles pneumonitis are variable and depend to some extent on the immunocompetence of the host as well as the duration and tempo of the disease. Ancillary studies may be necessary to establish the diagnosis in cases lacking classic histopathologic features.
Adult↗