The contribution of immunohistochemistry in the diagnosis of pediatric neoplastic lesions in the University of Puerto Rico, School of Medicine.

Immunohistochemistry has revolutionized the field of diagnostic pathology in the past fifteen years. Since then, it has been increasingly used as an adjunct to morphological diagnosis. The purpose of this retrospective analysis is to examine the value of this technique in the diagnosis of pediatric neoplasias in our laboratory. Forty eight pediatric cases, collected from January 1998 until May 1999, were reviewed, and classified in one of four categories: confirmed the morphological diagnosis, provided the definite diagnosis from a list of probable diagnoses, contributed by excluding other entities, and non-contributory. Immunohistochemistry confirmed the morphological diagnosis in 29 cases (60.4%), provided the definite diagnosis from a list of probable diagnoses in 13 cases (27.1%), was contributory by exclusion of other entities in 2 cases (4.2%), and was non-contributory in 4 cases (8.3%). In this preliminary study, we conclude that immunohistochemistry is being used in our laboratory mostly as a confirmatory tool for the definitive diagnosis of the lesions and once more exalts the utility of this technology in the field of diagnostic pathology.

Idiopathic orbital inflammation with intracranial extension. Case report.

Idiopathic orbital inflammation or orbital pseudotumor with intracranial extension is a rare condition. It consists of a nonspecific infiltrate of the fatty tissue of the orbit that extends through one or more foramina into the adjacent intracranial tissue. The lesion mimics an infectious or neoplastic lesion. The authors present a case involving the youngest patient yet reported with the broadest intracranial extension. Only 17 previous cases have been reported. The principal symptoms include decreased visual acuity and proptosis. Extension commonly develops through the superior orbital fissure into the middle cranial fossa and the cavernous sinus. The initial treatment is a regimen of high-dose steroids, with radiotherapy given in unresponsive cases.

Keratoconjunctivitis due to adenovirus type 8: report on a large outbreak.

A large nosocomial, community-acquired outbreak of keratoconjunctivitis due to adenovirus type 8 at a large military teaching hospital is described. One hundred thirty-two cases were identified with initial case confirmation by viral isolation and subsequent case confirmation based on clinical findings. Infection usually presented as a severe keratoconjunctivitis with 35% of infected patients developing subepithelial corneal infiltrates. Most infections were acquired by hand-to-eye contact or by tonometry while visiting the military eye service for other ophthalmologic reasons. Intrafamilial transmission of the virus occurred in 22% of cases with rare disease spread outside the family or hospital environments. The peak incidence occurred from April to August 1986 but was not confirmed by viral isolation until May 1986 when appropriate control measures were instituted. The delay in application of appropriate control measures was a major factor accounting for both the prolonged duration and epidemic nature of this kerato-conjunctivitis outbreak.

Corneal thinning as the sole manifestation of active undifferentiated connective tissue disease.

A patient with a two-year history of undifferentiated connective tissue disease had corneal thinning as the sole manifestation of its recurrence. Systemic immunosuppressive therapy was not indicated in view of the localized ocular disease. The patient was treated with tarsorrhaphy and ocular lubricants. One year later, when two new areas of localized thinning were found, a conjunctival wedge resection was done.

Focal glial differentiation and oncocytic transformation in choroid plexus papilloma.

The histiopathological features of a choroid plexus papilloma in a 27-year-old male are described. The tumor displayed marked oncocytic transformation and glial differentiation of the epithelium in areas in which there was also marked sclerosis of the fibrovascular cores. Non-membrane-bound bodies of intermediate filaments characterized ultrastructurally the cells with glial differentiation.

A variant of cerebral glioma called pleomorphic xanthoastrocytoma: case report.

A newly recognized type of cerebral astrocytoma has been described in the last 5 years among patients under the age of 30. The designation of pleomorphic xanthoastrocytoma has been suggested for this neoplasm on the basis of its unique histological features. These include abundant lipid droplets in the astrocytic cytoplasm. We report an additional case of this cerebral hemisphere astrocytoma, which (in common with 17 others reported before) occurred in a young patient. His postoperative course has been benign and he remains ambulatory and almost symptom-free 9 years after the initial tumor excision. The diagnosis of pleomorphic xanthoastrocytoma should be entertained in patients in whom a superficially placed intracerebral tumor (i.e., one that seems to be in contact with the meninges) develops during the juvenile years.

Diagnosis of viral encephalitis by brain biopsy.

Prompt and accurate diagnosis of viral encephalitis has acquired increased significance because of the encouraging results obtained in therapeutic trials with antiviral agents such as adenine arabinoside. Currently, brain biopsy remains the only reliable method to confirm the diagnosis of viral encephalitis. This communication, based on the analysis of eighteen confirmed cases of viral encephalitis, illustrates structural abnormalities common to these conditions and suggests biopsy handling procedures that appear most helpful in arriving at a prompt diagnosis. In addition to the traditionally well-known inflammatory changes, such as satellitosis, gliosis, and neuronophagia, a variety of intranuclear inclusion bodies are illustrated, and the judicious application of immunocytochemistry and electronmicroscopy is emphasized.