Contributed by Kongsak Loharamtaweethong, MD1; Bhakawat Chiamtrakool, MD2; Sukrit Viriyasakultong, MD3
Departments of 1Anatomical Pathology, 2Orthopaedic Surgery and 3Surgery, Faculty of Medicine, Vajira Hospital, Navamindradhiraj University, Bangkok, Thailand.
33-year-old Thai male patient presented with three weeks history of progressive bilateral lower limb weakness and paresthesia from below the level of the umbilicus. He was admitted at Sakaeo Crown Prince Hospital and first diagnosed with HIV/AIDS. He did not receive antiretroviral drugs before. Neurological examination showed loss of motor power of both lower extremities. Sensory loss was detected in all dermatomes below T10. Areflexia was observed in both legs. The meningeal sign was negative. The other systems revealed no remarkable change. The blood test displayed mild anemia, hyponatremia, and hypokalemia. His CD4 count was 14 cells/?L. Magnetic resonance imaging (MRI) of the lumbar spine showed a 1.4x1.3x1.0 cm round homogenous enhancing, T1/T2 Wi-low-to-iso/mild heterogenous hypersignal intensity, intradural mass lesion at L1 vertebral body level [Figure 1a]. Radiologically, the differential diagnosis included schwannoma, myxopapillary ependymoma, paraganglioma, and tuberculoma. He was treated but his symptoms did not improve. Few weeks later, he was referred to a specialist at our hospital. Surgeon performed lumbar laminectomy with gross total resection of tumor. Postoperatively, he developed progressive dyspnea with clinical suspicion for Pneumocystis jiroveci pneumonia (PJP) infection. He was treated but his clinical symptom got worse. Finally, he developed respiratory failure and expired two weeks after operation.
Microscopically, tumor consisted of interlacing fascicles of spindle cells with eosinophilic cytoplasm, and elongated nuclei, displaying mild atypia [Figure 1b]. Focal staghorn-like blood vessels were demonstrated [Figure1b]. Scattered areas composed of round cells with a primitive appearance were observed [Figure 1c]. Tumor necrosis was absent. The average mitotic count was 10 mitoses/10 HPF. Immunohistochemically, tumor cells were immunonegative for desmin [Figure 1d], ALK, CD23, CD34, CD68, EMA, GFAP, S100 protein and positive for smooth muscle actin (SMA) [Figure 1e], h-caldesmon [Figure 1f], smooth muscle myosin heavy chain (SMMHC) [Figure 1g] and vimentin. Ki-67 labeling index was 10-15%. AFB and GMS stains revealed no organisms. In-situ hybridization for EBER was positive (Fig 1h). What is your diagnosis?What is your diagnosis?