Schwannoma benigno do nervo intercostal simulando neoplastia de pulmão: relato de caso / Benign intercostal nerve schwannoma simulating pulmonary neoplasm: case report

Homem de 37 anos, branco, tabagista, foi internado com tosse seca e dor no hemitórax esquerdo (HE). Ao exame, macicez e murmúrio vesicular diminuído no terço médio do HE. A tomografia axial computadorizada de tórax revelou lesão expansiva nodular do 7º arco costal, projetando-se para o interior do HE, com densidade de parte mole e discreto realce pelo contraste. A histologia e a imuno-histoquímica foram compatíveis com schwannoma benigno. Consideramos que o diagnóstico de schwannoma benigno intercostal deve ser aventado ante toda massa intratorácica posterior ou lateral que curse com escassa sintomatologia e ausência de manifestações clínicas de malignidade.

Peripheral nerve sheath tumours: an ultrastructural study of 30 cases.

This report deals with the ultrastructural observations of 30 peripheral nerve sheath tumours [PNST], which include 25 schwannomas of acoustic nerve, one schwannoma of cauda equina, one neurofibroma from a case of Von Recklinghausen's disease, one pigmented neurofibroma of spinal nerve root and a malignant schwannoma of frontal region. Interdigitating slender cytoplasmic processes covered with a continuous layer of basal lamina constitute the single most important ultrastructural attribute of Schwann cells. Myelin formation was encountered in the cell processes of four out of 25 acoustic schwannomas. In four cases Microtubular arrays identical to that in an axon were seen in Schwann cells. These two observations require further support by additional cases of PNST studies by electron microscopy. The neurofibroma consisted only of Schwann cells and no ultrastructurally identifiable perineurial cells or fibroblasts were detected. The cells in the pigmented neurofibroma revealed submicroscopic features of both Schwann cell and melanocyte, indicating their common ancestry. A unique case of malignant schwannoma arising from frontal meninges is illustrated and it is emphasized that electron microscopy is mandatory for a correct histogenetic diagnosis of malignant tumours which occur at unexpected anatomical sites.