MR of Toxoplasma encephalitis: signal characteristics on T2-weighted images and pathologic correlation.

PURPOSE: Our goal was to determine if there are any T2-weighted MR signal characteristics of Toxoplasma encephalitis that might be useful in diagnosis and/or in gauging the effectiveness of medical therapy. METHOD: We retrospectively analyzed the MR, CT, thallium-201 SPECT brain scans, and medical records of 27 patients with medically proven (26) and biopsy proven (1) Toxoplasma encephalitis, supplemented by autopsy findings in 4 additional patients, 2 of whom had postmortem MR correlation. The neuropathologic literature was also reviewed. RESULTS: Among the 27 patients, we discovered three distinct imaging patterns. Ten (37%) patients had predominantly T2-weighted hyperintense lesions and had been on medical therapy an average of 3 days (excluding one outlier). Ten (37%) patients had T2-weighted isointense lesions and had received medical therapy an average of 61 days. Seven (26%) patients had lesions with mixed signal on T2-weighted images and had been on treatment an average of 6 days. Analysis of autopsy material from the four additional patients revealed the presence of organizing abscesses in three and necrotizing encephalitis in one, while the patient who had a brain biopsy demonstrated both types of pathologic lesions. In both cases having postmortem MRI, organizing abscesses appeared isointense to hypointense on T2-weighted images. CONCLUSION: There is a definite variation in the appearance of lesions of Toxoplasma encephalitis on T2-weighted images that precludes a definitive diagnosis based on signal characteristics alone. Pathologically, our data suggest that T2-weighted hyperintensity correlates with necrotizing encephalitis and T2-weighted isointensity with organizing abscesses. Furthermore, in patients on medical therapy the T2-weighted MR appearance may be a transition from hyperintensity to isointensity as a function of a positive response to antibiotic treatment, indicating that the signal change might be used to gauge the effectiveness of medical therapy.

Infections in children with human immunodeficiency virus/acquired immunodeficiency syndrome: an autopsy study of 30 cases in south Florida, 1990-1993.

Thirty autopsies performed on infants and children with HIV infection and/or AIDS were reviewed for the presence and type of infection. Twenty-six (87%) demonstrated evidence of infection in addition to HIV at the time of postmortem examination. Pathogenic bacterial infectious were the most frequently encountered, seen in 15 of the cases. Nine of the 15 (60%) were due to gram-negative rods, most commonly Pseudomonas aeruginosa. Infections with gram-negative organisms often involved multiple organ systems and were frequently undiagnosed both pre- and postmortem because of variability in culture results and difficulties in identification both clinically and in tissue sections. Discussion is presented of unusual staining characteristics and filamentous morphology found with these pathogens. Other pathogenic bacteria encountered were Klebsiella pneumoniae, Escherichia coli, Enterobacter sp., and Staphylococcus. Fungal infections due to Candida species were present in nine cases (31%) but were invasive in only two of these. One instance of Aspergillus meningo-encephalitis was noted. Proven viral infections were present in five children (three cytomegalovirus, one herpes simplex, and one adenovirus). Pneumocystis carinii pneumonia was diagnosed in five of the patients (17%), and one instance of disseminated Mycobacterium avium-intracellulare was encountered.

Metastasis of a myxoid leiomyosarcoma via the renal and hepatic portal circulation in a sarus crane (Grus antigone).

A 12-year-old female sarus crane (Grus antigone) developed a recurrent proliferative lesion in the subcutaneous tissue of the tarsometatarsus, which failed to respond to medical and surgical therapy. The crane was killed and microscopic examination of the tissues taken at necropsy revealed a myxomatous, poorly-differentiated sarcoma with metastasis to the liver and kidney. Immunohistochemical staining for muscle actin, smooth muscle myosin and vimentin were positive, indicating that the primary and metastatic tumours were leiomyosarcomas. Location of the metastatic lesions in only the portal venous system of the liver and veins of the kidney indicated that the route of metastasis was the portal circulation via the ischiatic vein, caudal mesenteric vein and both the renal-portal shunt and hepatic portal vein. This is the first report of metastatic subcutaneous leiomyosarcoma in an avian species.

Esophageal-atrial fistula resulting in systemic "meat and vegetable" emboli.

An 85-year-old demented woman died in the state hospital and her death was investigated by our office, based on allegations of neglect. At autopsy, a feeding catheter was found passed through an esophageal-atrial fistula into the left atrium. Fragments of striated muscle and plant wall (cellulose) embolized to the systemic organs including heart, kidney, and brain. Her dilated esophagus suggests a premortem esophageal motility disorder that contributed to the formation of the fistula. This is the first reported case of an esophageal-atrial fistula in the medical literature.

Congenital diabetes mellitus and fatal secretory diarrhea in two infants.

Two unrelated male infants presented with brittle insulin-dependent diabetes mellitus in the first days of life. Subsequently they each developed severe secretory diarrhea, with stool volumes of more than 100 ml/kg/day. Extensive biochemical and serological investigation failed to reveal the etiology of the diarrhea. The infants, cared for at different institutions, underwent therapeutic trials of various agents including loperamide, cholestyramine, prednisone, indomethacin, and somatostatin analogue, without response. Both infants succumbed to septicemia and malnutrition related to diarrhea and poor control of glycemia. At autopsy, both were found to have absence of islets of Langerhans in the pancreas, and diffuse dysplastic changes in small and large intestinal mucosae. In particular, the entire alimentary tract in each case was lined by epithelia most typical of foregut mucosa: secretory-type glands, absent crypts of Lieberkuhn, and absent villi. These cases are contrasted with previously-reported infants with congenital diabetes mellitus, and the possible interrelation of these two highly unusual findings, congenital diabetes mellitus and diffuse intestinal dysplasia, is examined.

Salivary gland oncocytes in African hedgehogs (Atelerix albiventris) mimicking cytomegalic inclusion disease.

The salivary glands from three African hedgehogs contained multiple foci of cytomegalic cells, which occasionally had a mild to moderate infiltrate of lymphocytes at the periphery. The cytomegalic cells were 35 to 40 microns in diameter with abundant acidophilic granular to hyalin cytoplasm. The nuclei were enlarged with clumped marginalized chromatin and a large, (6 to 8 microns in diameter) central, brightly eosinophilic nucleolus that had the appearance of an inclusion body by light microscopy. Histochemically most of the cytomegalic cells contained cytoplasmic metachromatic granules with Feyrter's thionine inclusion stain. Scattered cells at the periphery of the cytomegalic foci contained periodic acid-Schiff-positive cytoplasmic granules. Ultrastructurally the cytomegalic cells contained numerous tightly-packed, often bizarre, enlarged mitochondria that completely filled the cytoplasm. The nucleus consisted of a dense central core of chromatin associated with the nucleolus and the remaining chromatin was clumped and marginalized. Nuclear and cytoplasmic virions consistent with cytomegalovirus were not present. Histochemical stains of the nucleus for heavy metals were negative. The ultrastructural and histochemical findings of the cytomegalic cells were consistent with oncocytes. Previous reports in the literature of similar cells in the salivary glands of insectivores appear to have been erroneously described as cytomegalovirus infections.

Disseminated Klebsiella rhinoscleromatis infection.

A 35-year-old obese black American woman presented with nausea, vomiting, diarrhea, fever, cough, and chest pain of 2 weeks duration. She was pancytopenic and acidotic, with respiratory failure and hypotension. A diagnosis of septic shock was made, and the patient died 48 hours after admission. Blood cultures were positive for organisms that were reported to be Klebsiella rhinoscleromatis. At autopsy she had massive hepatic necrosis with numerous Mikulicz's cells. The lungs, spleen, and bone marrow were also involved. To our knowledge, this is the first report of a case of systemic infection with K rhinoscleromatis.

Congenital syphilis and necrotizing funisitis.

During the past 5 years we encountered 16 cases of necrotizing funisitis, a deeply seated inflammatory process within the matrix of the umbilical cord, and established that all of them were associated with maternal and congenital syphilis. During that time necrotizing funisitis was not found to be associated with any other infection. The relationship was unexpected on the basis of current knowledge of the condition, but we found the older medical literature documents syphilis as the virtually specific cause of deep funisitis with angiophlebitis. Necrotizing funisitis has a characteristic macroscopic appearance, the "barberpole" cord, that permits the presumptive diagnosis of congenital syphilis at the time of birth.

CT, MR, and pathology in HIV encephalitis and meningitis.

The value and limitations of CT and MR in human immunodeficiency virus (HIV) infection of the brain was determined by a retrospective analysis of the CT scans (22) and MR images (7) in 22 patients with pathologically proved HIV encephalitis (21) or meningitis (1). Our clinical-radiologic-pathologic correlation suggested that, especially in the early stages of the disease, CT and MR were relatively insensitive in detecting the primary changes of HIV encephalitis. The multiple bilateral diffuse microscopic glial nodules with multinucleated giant cells of HIV found at autopsy in both gray and white matter were usually not directly visualized by either CT or MR. Secondary, nonspecific changes, however, were seen. These included cortical atrophy, found in virtually all patients with HIV encephalitis, and HIV-induced foci of demyelination found in the minority of cases. On CT the latter were seen in the white matter as nonenhancing, nonmass-producing areas of low density; on MR they were seen as frequently progressive high-intensity signal abnormalities on T2-weighted images, usually in the periventricular white matter and centrum semiovale. MR was more sensitive in detecting these demyelinative lesions than was CT. The clinical diagnosis of HIV encephalitis usually antedated the radiographic diagnosis. In HIV meningitis, contrast CT was more definitive than MR, showing striking enhancement of the subarachnoid spaces, although MR was more sensitive in detecting the secondary parenchymal changes.

Transmissibility of a neurofibromatosis-like disease in bicolor damselfish.

A neoplastic disease that affects a common species of marine fish, the bicolor damselfish (Pomacentrus partitus), on Florida reefs consists of multiple, disseminated neurofibromas (including plexiform lesions), malignant schwannomas, and hyperpigmented epidermal lesions. Based on similarities to von Recklinghausen neurofibromatosis, we have termed this disease damselfish neurofibromatosis. Previous surveys of the prevalence of fish with damselfish neurofibromatosis on Florida reefs demonstrated a distribution pattern of cases consistent with what would be expected for an infectious disease. The transmissibility of damselfish neurofibromatosis was assessed by inoculations of homogenized tumor tissue s.c. and i.p. into healthy bicolor damselfish. This protocol resulted in the development of Schwann cell tumors, identical to the naturally occurring lesions, at the injection sites in approximately 84% of inoculated fish. These tumors appeared within an average of 5 mo of inoculation for juvenile fish and 14 mo for adults. Experimentally produced tumors appeared to arise in host fish by the neoplastic transformation of host nerves rather than by transplantation and proliferation of tumor cells from the donor fish. This finding suggests that an infectious, transmissible agent such as a virus may be the etiological agent responsible for production of neurofibromas and other Schwann cell tumors in this species of fish.

Pathology of the heart in acquired immunodeficiency syndrome.

Data on 54 persons who died of acquired immunodeficiency syndrome were reviewed for lesions of the heart. These persons met the criteria of the Centers for Disease Control (Atlanta) for acquired immunodeficiency syndrome. Pathologic changes were seen in 30 patients (55%). Changes were seen in the endocardium (17%), myocardium (83%), and epicardium (3%). The most frequent finding was lymphocytic myocarditis. Six of these were due to Toxoplasma myocarditis. Only one patient succumbed to cardiac arrest.

The initial presentation of fatty liver of pregnancy mimicking acute viral hepatitis.

Acute fatty liver of pregnancy, a disease of the 3rd trimester of pregnancy, may have varied presentations. An unusual initial presentation of acute fatty liver of pregnancy mimicking an acute viral hepatitis is reported herein. Osmium tetroxide preparation of pathological specimen for the diagnosis of acute fatty liver of pregnancy is also discussed.

Acquired immunodeficiency syndrome associated with Acanthamoeba infection and other opportunistic organisms.

A 29-year-old Haitian man with acquired immunodeficiency syndrome presented with nasal obstruction and epistaxis. A computed tomogram of the head showed thickened nasal and paranasal sinus mucosa. A biopsy specimen of the turbinate disclosed inflammatory tissue containing amoebic trophozoites. The patient was empirically treated with rifampin and ketoconazole. He died four months after biopsy of other complications of acquired immunodeficiency syndrome. At autopsy, the amoebic infection was found only in the paranasal sinuses, a calf nodule, and in an intradermal abscess in the left leg. Pneumocystitis carinii pneumonia, Mycobacterium avium-cellulare in the liver and retroperitoneal lymph nodes, cytomegalovirus infection of the adrenal glands, and Kaposi's sarcoma in the spleen were additionally present. The organism was cultured and studied by electron microscopy, dark-field microscopy, and immunofluorescence.

Cytomegalic inclusion virus encephalitis in patients with AIDS: CT, clinical, and pathologic correlation.

The computed tomographic (CT) scans of 10 patients with acquired immunodeficiency syndrome who had central nervous system (CNS) involvement by cytomegalovirus (CMV) were retrospectively reviewed and correlated with clinical data and pathologic findings. Diagnosis was established in all 10 patients by autopsy, which showed the pathognomonic "owl's eye" intracellular inclusions of CMV. In six patients CMV caused an initial CNS infection that was directly responsible for the patient's progressive encephalopathy and death. In four patients CMV caused a superimposed nondominant CNS infection that had no clinical expression in two. Cortical atrophy and mild hydrocephalus ex vacuo were seen on CT in all 10 patients. Positive findings on CT that could be attributed to infection with CMV were present in only three of the 10 patients, and in these three symptomatic cases autopsy correlation revealed that CT underestimated the degree of CNS involvement. In the other three symptomatic patients, CT showed no parenchymal abnormalities, while autopsy demonstrated diffuse cerebral involvement. In the four patients whose CNS was secondarily involved by CMV, CT showed changes proven at autopsy to be related only to the dominant infection with Toxoplasma gondii and to postoperative hematomas. CT did not demonstrate any abnormalities at the sites of CMV involvement, which were found at autopsy in this latter group. It was concluded that CT is not very sensitive for the detection of CMV encephalitis.

Central nervous system disease in acquired immunodeficiency syndrome: prospective correlation using CT, MR imaging, and pathologic studies.

A prospective study compared the abilities of high-resolution computed tomography (HRCT) and magnetic resonance (MR) imaging in detection and evaluation of central nervous system disease in neurologically symptomatic patients with acquired immunodeficiency syndrome (AIDS). Eighteen CT scans and 19 MR images in 14 patients were compared. HRCT images with contrast material enhancement were superior to unenhanced 0.35-T MR images for differentiating a lesion from surrounding edema, discriminating between lesions in close proximity, locating lesions for biopsy, judging lesion activity, detecting small cortical lesions with minimal edema, and spatial resolution. MR imaging was superior to CT scanning in evaluation of white-matter lesions and detection of small lesions surrounded by edema. MR imaging exhibited higher contrast resolution and greater sensitivity. Complementary uses of MR and CT imaging are suggested.

Cranial CT in acquired immunodeficiency syndrome: spectrum of diseases and optimal contrast enhancement technique.

A retrospective review of cranial CT scans obtained over a 4 year period in patients with acquired immunodeficiency syndrome (AIDS) and documented central nervous system (CNS) pathology is presented. The spectrum of diseases and the value of CT in detecting new, recurrent, and superimposed disease processes were determined. Fifty-one AIDS patients with confirmed CNS pathology were identified. Six of them had two coexistent diseases. Opportunistic infections predominated, especially Toxoplasma encephalitis and cryptococcal meningitis, while tumor was seen infrequently. Initial CT was positive in 76% of cases. In contrast to meningeal processes, where it was not very effective, CT was very sensitive in detecting most parenchymal disease processes. Characteristic although not pathognomonic CT patterns were found for certain diseases. Improvement or resolution of CT abnormalities in patients on medical therapy for Toxoplasma encephalitis correlated well with clinical improvement. Recurrence of CT abnormalities correlated well with medical noncompliance. The optimal contrast enhancement technique for detecting CNS pathology and for monitoring the effectiveness of medical therapy was also evaluated by a prospective study in which both immediate (IDD) and 1 hr delayed (DDD) double-dose contrast CT scans were compared. The examination found to be diagnostically superior in 30 of the 41 IDD/DDD studies was the delayed scan. It is recommended that CT be used routinely and with the 1 hr DDD scan to evaluate and follow AIDS patients with neurologic symptoms and/or signs.

Immediate causes of death in acquired immunodeficiency syndrome.

We evaluated the immediate causes of death in 54 adults who underwent an autopsy and were diagnosed as having died of the acquired immunodeficiency syndrome between April 1980 and October 1983. The study group included 25 Haitians, 19 homosexual men, five intravenous drug abusers, two hemophiliacs (type A), and three with no known risk. Fourteen died of central nervous system diseases: 11 of Toxoplasma encephalitis, one of progressive multifocal leukoencephalopathy, one of viral encephalitis, and one of intracerebral hemorrhage. Thirty died of respiratory failure; 16 of Pneumocystis carinii pneumonia, ten of cytomegalovirus pneumonia, one of multiple infections, one of interstitial pneumonia, and two of bacterial pneumonia. Two died of overwhelming generalized infections: one of Mycobacterium avium-intracellulare and one of listeriosis. Six died of disseminated Kaposi's sarcoma, while the remaining two persons died of Toxoplasma myocarditis (one) and one of shock resulting from a percutaneous liver biopsy, respectively. There were differences in the immediate causes of death between Haitians and homosexuals as follows: 63% of homosexual men died of either P carinii pneumonia or Kaposi's sarcoma vs 20% of Haitians. In contrast, 72% of Haitians died of other opportunistic infections as compared with 21% of homosexuals. There has not been an increase in the proportion of cases diagnosed premortem since 1982 and overall, only 32 (58%) were diagnosed premortem; the rest were diagnosed only at autopsy. This study provided evidence that 42% died of currently untreatable diseases.

Frequency and anatomic distribution of lymphadenopathic Kaposi's sarcoma in the acquired immunodeficiency syndrome: an autopsy series.

Histologic material from 52 autopsies of persons who had died of the acquired immunodeficiency syndrome (AIDS) were reviewed. The study group included 23 Haitians, 19 homosexual men, five intravenous drug abusers, two hemophiliacs (type A), and three persons at unknown risk. Nineteen of the patients (36.5 per cent) had typical Kaposi's sarcoma alone, but 49 (94.2 per cent) had the inflammatory variant of Kaposi's sarcoma as well as typical Kaposi's sarcoma. Inflammatory Kaposi's sarcoma was found in all risk groups studied. In all cases of typical Kaposi's sarcoma, histomorphologic transitions of inflammatory Kaposi's sarcoma to typical Kaposi's sarcoma were observed. Lymph nodes and spleen were the organs most commonly involved by both typical and inflammatory Kaposi's sarcoma. The findings indicate that Kaposi's sarcoma is more common and has a wider morphologic spectrum in AIDS than is generally appreciated.