Background:According to World Health Organization (WHO) classification of tumors, malignant peripheral nerve sheath tumors (MPNST) encompass the tumors, which were previously termed as malignant schwannoma, neurogenic sarcoma, and neurofibrosarcoma. These are rare tumors constituting only 5% of all malignant soft tissue tumors. As per their name, they arise from the malignant proliferation of cells forming sheath of a nerve root. They cause spinal cord compression, secondary changes in the surrounding bone with variable amount of tumor tissue going into the paraspinal space. However, purely intraosseous origin of the MPNST with no visible connection with a nerve root or dura is rare and few cases have been described in the literature.Case Description:We present a primary intraosseous MPNST arising from the body of a thoracic spine with a minimal intraspinal component. However, there was a huge tumor part occupying the paraspinal and retrospinal region. The latter component was so large that it extended to lie just beneath the skin. The intraspinal component was confined to only one level. The giant extraspinal part was spanning multiple corresponding spinal level. We could not find such presentation in the literature.Conclusion:Gross total removal (GTR) followed by adjuvant chemo-radiotherapy is the optimal treatment for MPNST of spine. In case of multiple laminectomy or gross spinal instability, spinal instrumentation makes the treatment protocol complete.

Background:Histiocytic sarcoma (HS) is a rare aggressive malignant neoplasm of hematopoietic cell origin showing features of fever, weight loss, adenopathy, hepatosplenomegaly, and pancytopenia. Primary histiocytic sarcoma of spine without involvement of lymph nodes, bone marrow or systemic features is very rare. Due to highly malignant, aggressive behavior and frequent local and distant metastases, prognosis of histocytic sarcoma is poor.Case description:We report a case of primary extranodal variety of histiocytic sarcoma without involvement of bone marrow at extradural location of thoracic spine. Immunohistochemistry panel ruled out other more common lesions in this location. We could not find such presentation of extradural histiocytic sarcoma at the thoracic region in the literature.Conclusion:Primary involvement of extradural space by histiocytic sarcoma could arise from the proliferation of multipotent hematopoietic stem cells which are left in this space embroyologically.

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