Immunohistochemical analysis of thymoma. Evidence for medullary origin of epithelial cells.

The histologic organization of lymphoid and nonlymphoid (epithelial and interdigitating) cells in a thymoma has been compared to that of the normal thymus. Enzyme and immunohistochemical methods were applied, using both conventional antisera (to cytokeratin) and monoclonal antibodies (to epithelial cells, HLA-DR and lymphoid subsets). Throughout the tumor, the epithelial cells shared phenotypical similarities with the epithelial cells of thymic medulla (RFD-4 positive, cytokeratin strongly positive, and HLA-DR essentially negative). On the other hand, the lymphoid cells were heterogeneous in phenotype and distribution, and "mimicked" the distribution seen in the normal infant thymus. Immature thymocytes of cortical type (TdT+, OKT6+, OKT3-) were predominant in the areas with moderate lymphocytic infiltration (ML). Mature T-lymphocytes (TdT-, OKT6-, OKT3+) were found mainly in areas with scanty lymphocytes (SL) together with an additional population of HLA-DR positive interdigitating and HLA-DR+, OKT6+ Langerhans'-type cells. These findings indicate that in thymoma tissue, the lymphoid elements of cortical type are apparently surrounded by an inappropriate (medullary) epithelium.

Malignant mesothelioma. The University of Minnesota experience.

Between 1950 and 1981, 31 patients with mesothelioma were treated at the University of Minnesota. An average of 0.2 to 0.6 patients were seen per year between 1950 and 1970, and since 1970 there has been an average of 1.4 to 2.4 patients per year. Twenty-seven of the 28 patients with malignant mesothelioma are known or presumed dead. Mesotheliomas occurred in all areas of Minnesota, and 28.6% of the patients had a definite history of asbestos exposure. This was also a probable cause of the disease in an additional 25% of patients. The clinical findings and course of the disease were similar to other series. The median survival of all patients was eight months. Doxorubicin-treated patients survived a median of 16 months (range, 2-36 months). Malignant mesothelioma is being increasingly recognized in Minnesota and has a grim prognosis in spite of doxorubicin therapy.

Dipeptidyl(amino)peptidase IV (DAP-IV) histochemistry on normal and pathologic lymphoid tissues.

The enzyme glycyl-proline-naphthylamidase (dipeptidyl-amino-peptidase IV), (DAP-IV) has been histochemically analysed in normal and pathological specimens of different lymphoid tissues. In all the tissues examined, the enzyme appeared to be highly specific for T cells. Using chloroformacetone fixation and sections of proper thickness, DAP-IV could be successfully demonstrated in cortical thymocytes, which exhibited weak reactivity, as well as in medullary thymocytes which showed a more intense and variable reactivity. A similar reactivity was observed in T cells of peripheral blood, lymph node, and spleen. Various acute lymphoblastic and nonlymphoblastic leukemias and malignant lymphomas were studied using the histochemical method for DAP-IV. Malignant cells from all the acute leukemias and from the B-cell lymphomas were DAP-IV unreactive, while strong reactivity was observed in one case of T-CLL and one case of T-PLL. The possible relationship of DAP-IV positivity pattern with T-cell maturation and its potential use as a diagnostic tool in lymphoproliferative disorders are discussed.

Enzyme histochemistry on normal and pathologic paraffin-embedded lymphoid tissues.

So far, enzyme histochemical examination has been applied, with few exceptions, either to tissue imprints or to cryostat sections of freshly collected samples. This procedure is not easily applicable in routine histopathologic examination. In this study, a simplified tissue embedding procedure is presented which can be performed using an automatic tissue changer. The paraffin embedded samples can be used for both conventional histopathologic examination and for demonstrating enzymes in sections. The enzymes studied (alkaline phosphatase, alpha-naphthyl acetate esterase, acid phosphatase, tartrate resistant acid phosphatase, ATPase, peroxidase, and chloroacetate esterase) gave comparable results in formalin-fixed cryostat sections and paraffin sections in both normal and pathologic lymphoid samples. The only exception was ATPase, which could not be demonstrated on paraffin-embedded material. The technic described has broad application in the analysis of lymphoid diseases.

Lumbar epidural Ewing sarcoma. Light and electron microscopic investigation.

The clinicopathological findings in a child with extraskeletal Ewing sarcoma are described. The patient complained of pain in the lower back and difficulty walking. An extraskeletal, epidural, friable tumor, 2-3 cm long was removed from the epidural space. It had no relationship with the bone structures. Light and electron microscopic examination of the tumor led to the diagnosis of Ewing sarcoma. The morphological aspects of this neoplasia and the problem of the differential diagnosis with other small cell tumors of the epidural space are discussed.

Gliomatosis cerebri diffusa. A case report.

The clinico-pathologic findings in an additional case of gliomatosis cerebri are reported: a 60-year-old woman died 8 months after the onset of a progressive deterioration of both the neurologic and mental conditions. Neuropathologic examination disclosed wide demyelination of both hemispheres, communicating through the corpus callosum, extending downward along the internal capsule to the brainstem structures. Cellular stains showed the presence of elongated astrocytes, multinucleated cells, mitotic and anaplastic figures, involving the demyelinated areas and the neighboring regions, and allowed the diagnosis of gliomatosis cerebri diffusa. The nosologic and pathogenetic aspects of this rare entity are discussed.

Arteriovenous aneurysm of the vein of Galen. A clinical, angiographic CT scan and neuropathological study.

An autopsied case of arteriovenous aneurysm of the vein of Galen in a 31/2-month-old female is reported. Arteriovenous aneurysm of the vein of Galen is a rare vascular malformation of the central nervous system consisting of a saccular dilatation of the vein which receives blood shunted through enlarged arteries. These peculiar structural and hemodynamic characteristics differentiate this particular malformation from the other AVMs of the central nervous system. In infants the arteriovenous aneurysm of the vein of Galen is characterized clinically by hydrocephalus and cardiomegaly. In the present paper the clinical features and diagnostic indications are discussed and, in particular, the role of computerized cranial tomography (CT) is emphasized as a rapid and noninvasive procedure for detection of intracranial disorders.

[Four cases of Creutzfeldt-Jakob's disease (author's transl)]. / La malattia di Creutzfeldt-Jakob considerazioni su quattro casi.

The clinico-pathological features of 4 cases of Creutzfeldt-Jakob disease, a transmissible virus dementia, are reported. The onset of the disease varied between 54 and 81 years of age: the course is dramatic and the demise occurs 1-4 months after the onset of symptoms. The clinical picture includes mental deterioration with amnesia, aphasia, apraxia and neurologic symptoms, mainly consisting in progressive rigidity and myoclonus. All cases show the typical 1/sec pseudorithmic spikes on EEG. Histological changes include severe astrocytosis of the cerebral cortex, status spongiosus and mild neuronal loss. The changes are more marked in the parieto-occipital lobes. Criteria of clinical and pathological diagnosis are reviewed. The precautions to be taken in handling biological as well as bioptic and autoptic specimens are emphasized, in order to avoid accidental transmission of the disease. It seems essential to institute a register of cases of Creutzfeldt-Jakob disease in Italy to assess the incidence and diffusion of the disease in our country.