No abstract

We report the first case of an extranodal follicular dendritic cell (FDC) tumour localized in the nasopharynx of a 44-year-old male patient. The tumour cells were characterized immunohistochemically by strong expression of CD21, HLA-DR and vimentin and focal expression of CD68 and cytokeratin. Electron microscopic examination revealed desmosomal cell junctions between adjacent cell processes. Molecular genetic analysis using polymerase chain reaction (PCR) showed germline configuration of immunoglobulin and T-cell receptor genes. Epstein-Barr virus (EBV) genomes were detectable by PCR. After complete surgical tumour removal and radiotherapy the patient is disease-free 20 months after the initial diagnosis.

Brief reports 437ossification where the deposition is localized1*2. The young age of our patient also corresponds to that for the underlying disease, pulmonary tuberculosis, which is prevalent in our locality. 2.3. 4.References 5. 1. Dail DH. Metabolic and other diseases. In Dail DH. Hammar SP ed. Pulmonary Patfiology. New York: Springer-Verlag. 1988: 551-554. Wells HG. Dunlap CE. Disseminated ossification of the lungs. Arch. Pathol. Lab. Med. 1943; 35; 420-426. Wilson WR, Sasaki R. Johnson CA. Disseminated nodular pulmonary ossification in patients with mitral stenosis. Circulation 1959: Popelka CG. Kleinerman J. Diffuse pulmonary ossification. Arch. Intern. Med. 1977; 137; 523-525. Kuplic JB. Higley CS, Niewoehner DE. Pulmonary ossification associated with long-term busulfan therapy in chronic myelogenous leukemia. Am. Rev. Resp.

Twenty-eight cases of nasopharyngeal angiofibroma were studied immunohistochemically for cytoskeletal phenotyping of stromal cells. Electron microscopy was also used to study the ultrastructure of five of the tumors. All typical stromal cells showed intensive immunostaining for vimentin, but were negative for smooth muscle actin and desmin. Ultrastructurally, most of these cells appeared to be exclusively fibroblasts. However, in some areas stromal cells were seen that morphologically resembled myofibroblasts by their shapes and arrangement, and were characterized by the coexpression of vimentin and smooth muscle actin. Electron microscopy confirmed their myofibroblastic nature. The present study showed that the typical stromal cells in nasopharyngeal angiofibromas were fibroblasts and not myofibroblasts. In these tumors myofibroblasts occurred only focally, in connection with fibrotic areas and exclusively as a vimentin+/actin+cytoskeletal phenotype. This indicates that myofibroblasts are not primary stromal tumor cells in nasopharyngeal angiofibromas, but occur due to regressive changes.