A 71-year-old Italian woman presented a 2-month history of numbness and pain involving the left leg. She underwent orthopedic evaluation and articular ankle echography for the diagnostic suspicion of Baker cyst, that were negative. She also underwent lumbosacral MRI that did not show any signs of degenerative or traumatic injuries. One month later she developed radicular pain in both legs with hypoesthesia. She underwent cervico-dorsal MRI with contrast that showed a gadolinium-enhancing lesion within the spinal cord at T5-6 with maximum diameter of 11 mm. In the axial sequences the lesion seemed to be completely intramedullary without any signs of bulging. The neuroradiological aspects of the lesion were interpreted as an intramedullary astrocytoma or ependymoma. Neurologically, she had symmetric tendon reflexes, exaggerated in the legs, Babinsky sign on both legs, moderate paraparesis, hypoesthesia and dysesthesia of the entire left leg and left thorax below the T5 metamer. One month after the first MRI, during recovery, she underwent another dorsal MRI with contrast, which confirmed the presence of this intramedullary gadolinium-enhancing lesion at level T5-T6: this was interpreted as hemangioblastoma or ependymoma but, according to the neuroradiologist, it was impossibile to exclude other diagnostic hypothese (fig.1). As a matter of fact, the worsening of neurological symptomatology, expecially the progression of paraparesis, persuaded us to adopt a decompressive surgical strategy and so the patient underwent surgical treatment. A T5-T6-T7 laminectomy was performed, and the dura was opened. There was no evidence of extramedullary abnormality. Posterior longitudinal myelotomy was performed and a well-circumscribed grayish-red lesion was exposed. A histological sample for the extemporary and definitive examination was taken, which showed a histological pattern of small-cell tumoral lesion. For this reason a complete removal with CUSA was performed.
The definitive histological examination of the specimen revealed an inflammatory lesion which was composed of a mixed infiltration of mature B and T lymphocytes, with plasma cells and macrophages. Abundant vascular channels, often with hyperplastic endothelium, and focal fibroblastic reaction were observed. The macrophages were occasionally organized to form granulomas. This mass of non-neoplastic inflammatory cells of unknown origin was also studied using histochemical technique (PAS and Ziehl Neelsen), but no fungal or bacteria were found. Also the non-neoplastic nature of the lesion was demonstrated by immunohistochemical studies, which confirmed the mixed nature of lymphocytes, and by the polyclonality of plasma cells with positivity for kappa and lambda light chains of immunoglobulins (fig 2, 3). Postoperatively, there was a complete regression of radicular pain and paresthesia in the left thorax and leg. Postoperative dorsal MRI with contrast was performed 10 days after surgery and confirmed complete removal of the lesion without any signs of residual disease (fig.4a). Postoperative laboratory and radiological exams was performed, such as Toxotest, BK test and Chest RX for the diagnostic hypothesis of toxoplasmosis, TBC, histiocitosys X, or sarcoidosis, that were all negative. We also performed the liquor level of cerebrospinal fluid angiotensinconverting enzyme (ACE) in suspected neurosarcoidosi, which showed a value of 3.2 nmol/mL/min, non discriminatory. The patient was discharged on the seventh postoperative day. At follow up thoracic MRI with contrast was performed 3 (fig.4b) and 10 months (fig.4c) after surgery, and did not show any signs of disease.