Aspecific inflammatory lesion (histiocytosis?) simulating intramedullary astrocytoma. Case report

We report an exceptional case of aspecific inflammatory lesion of the thoracic spinal cord simulating an intramedullary glial tumor. Patient history was characterized by progressive spastic paraparesis with urinary incontinence; MR imaging (T4-T5) showed an enhancing intrinsic mass lesion. Myelotomy enabled partial resection of grayish astrocytoma-like tissue. Only light microscope examination was possible and disclosed aspecific inflammatory tissue composed of eosinophils, lymphocytes and histiocytes. After the operation, the patient improved promptly and no further therapy was administered. Control MRI after four months, one year and two years showed complete disappearance of the intramedullary mass lesion and the patient remained clinically stable with no other signs of disease. Since electron microscopic as well as immunohistochemical studies were not available, a definitive histological diagnosis was not possible. However on the basis of some clinical similarities with cases of isolated histiocytosis X of the CNS reported in the literature, we suggest that a diagnosis of isolated intramedullary eosinophilic granuloma could be reasonable.