Fine-Needle Aspiration Cytology of Ewing’s Sarcoma of Thoracic Spine with Extension into the Intradural Space

Ewing’s sarcoma/peripheral primitive neuroectodermal tumor is a small, round, and blue cell malignancy that occurs most often in bone and soft tissues of children and young adults. The intraspinal manifestation of the disease is rare, and when present, this is often misdiagnosed with other varieties of primary spinal tumors. Fine-needle aspiration cytology (FNAC) plays important role in the early diagnosis of these cases. We report such a case of Ewing’s sarcoma of thoracic spine with extension into the intradural space, which was initially suspected to be a case of metastatic lesion in an 18-year-old boy. 1. Introduction Ewing’s sarcoma family of tumors are a group of small round-cell neoplasms, which include Ewing’s sarcoma (EWS), primitive neuroectodermal tumor (PNET), Askins tumor, PNET of the bone, and extraosseous Ewing’s sarcoma (ESS) [1]. Ewing’s sarcoma/peripheral primitive neuroectodermal tumor is presumed to be in neuroectodermal children and young adults. The intraspinal extraosseous Ewing’s sarcoma (CNS-ESS) is extremely rare and often misdiagnosed. 2. Case Report An 18-year-old boy was admitted to Neurosurgery Ward of RNT Medical College, Udaipur Rajasthan, with chief complaints of progressively increasing dullaching pain in the lower back and both limbs and tenderness at D7, D8 vertebral region. There was a history of loss of appetite and malaise. The patient was thin built and on general examination there was a mild pallor. Systemic examination did not reveal any abnormalities except weakness (power 3/5) in both lower limbs and decrease in sensation of touch. Investigation revealed haemoglobin 9？gm.%, total leukocyte count 8200？cells/mm？cu with 70% polymorphs and 26% lymphocytes. Erythrocyte sedimentation rate was 60？mm at the end of 1 hour. The urine examination and bone marrow examination did not reveal any abnormality. Tuberculin test was negative. Chest radiograph was normal. CT scan (Figure 1) of the spine showed an expansile lytic lesion of posterior element of D7 vertebrae involving the spinous process, associated with heterogeneously enhancing soft tissue component, which was extending from D7 to D9 vertebrae. Figure 1 The soft tissue component was seen involving the thecal sac, lamina, and spinous process of D7 and causing compression and displacement of spinal cord anteriorly. MRI of the spine (Figure 2) reveals an expansile lesion of posterior element of D7 involving spinous process and neural arch, associated with fairly large, enhancing soft tissue component in posterior paraspinal region extending from D6-D7 to D8-D9