Abstract

A 20 year- old Caucasian man presented with a 10- day history of back pain, low- grade fever, weakness in the legs. At physical examination, absence of breath sounds at the left hemithorax, anesthesia under 5th thoracal vertebra(t5), flask paraplegia, urinary and fecal retention were detected. Chest x- rays showed a well- demarcated mass occupying the entire left hemithorax. Computerized tomography and ultrasound studies demonstrated that the mass was solid and homogeneous. Myelography revealed total block at T5. Myelo - CT: The tumoral mass which partially filled the spine, pushed the spinal cord to the posterior at T5. The left posteriolateral thoracotomy revealed a non- resectable intrathoracic neoplasm which invaded the anterior face of thoracal vertebrae 3 and 4. The tumoral mass was excised subtotaly. During the hospitalization paraplegia developed postoperatively. The patient did not agree to receive adjuvant radiotherapy or chemotherapy and died in the 6 th month following diagnosis. The surgical specimen was soft, flesh-like, extensively hemorrhagic and necrotic mass. H.E sections revealed a cellular undifferentiated neoplasm with a uniform structure and lobular growth pattern, divided by inconspicuous fibrovascular septae. The neoplastic cells generally featured small size, round- shaped, vesicular nuclei, irregular chromatin and scanty, cytoplasm. Histochemical staining for PAS, PAS- D and Gomori's reticulin were done. Tumor cells showed diffuse positivity for PAS staining. Immunohistochemical staining for desmin, vimentin, myoglobin, CAM 5.2, LCA, NSE and PGP 9.5 were performed. The tumor cells were positive for NSE and PGP 9.5 diffusely. Ultrastructurally, dense core (neurosecretory) granules and cell processes were recognized.