myeloid sarcomas ( ms ) or granulocytic sarcomas have been associated with acute myelogenous leukemia , myelodysplastic , or myeloproliferative disorder . uncommonly , they can occur alone without peripheral blood or bone marrow ( bm ) evidence of leukemia . ms is a neoplasm of immature granulocytes , monocytes , or both involving any extra - medullary site . a 17-year - old female presented with complaints of headache and blurred vision in both eyes for 1 month . she also had history of bilateral lower limb weakness more on left side for 1 month and multiple episodes of generalized seizures for 20 days . on examination she could count fingers close to the face bilaterally with fundi showing papilledema in both eyes . she had grade 5 power in both upper limbs , grade 3 power in the right and grade 1 in the left lower limb respectively . her magnetic resonance imaging ( mri ) showed a 5.9 cm  4.6 cm  2.7 cm bilateral middle 1/3 para sagittal extra - axial mass . the tumor showed restriction in the diffusion - weighted images and increased perfusion in the perfusion - weighted images . mr venogram showed blockage in middle of the superior sagittal sinus due to tumor invasion . she underwent bi - parietal parasagittal craniotomy and subtotal excision leaving the tumor within the sinus . there was no infiltration of bone by the tumor and the bone flap was replaced back . postoperative period was uneventful and there was mild improvement in her weakness in both lower limbs . ( d ) magnetic resonance venogram showed the blockage of superior sagittal sinus in the middle . ( h ) sagittal postoperative contrast images showed residual tumor within the sinus on histopathology tumor was composed of sheets of round to oval cells with vesicular nuclei , nuclear indentation in many and scant to moderate faint eosinophilic cytoplasm . in addition , few eosinophils , neutrophils and lymphocytes were seen admixed with the tumor cells . immunohistochemistry showed strong and diffuse positivity for myeloperoxidase ( mpo ) , whereas cd34 was focally positive and tumor was negative for epithelial membrane antigen , leucocyte common antigen , cd99 , cd20 , cd3 and desmin [ figures 2 and 3 ] . ( a - c ) microphotograph showing a polymorphous infiltrate with many immature round cells ( a : h and e , 100 , b : h and e , 200 , c : h and e , 200 ) . ( d ) tumor cells positive for myeloperoxidase immunohistochemistry ( 400 ) paraffin section of chloroma showing ( a ) round to oval cells with eosinophilic cytoplasm , nuclear indentation and maturation into neutrophils with ( b ) focal immunopositivity for cd34 ( a : h and e , 400 , b : avidin biotin complex immunoperoxidase , 400 ) further workup done to evaluate systemic disease showed no evidence to support it . her bm biopsy and peripheral blood smear tests patient was put on cyclophosphamide based chemotherapy and remained asymptomatic after 6 months of follow - up . myeloid sarcoma is also called as chloroma due to its greenish hue resulting from the presence of myeloperioxidase . in the cranial cavity it then traverses the haversian canals , spreads up to the subperiosteum , breaches the dura and manifests as an extra - axial lesion occupying the subarachnoid space . the tumor may penetrate the pia , invade the parenchyma and present as an intra - axial mass . the who described myeloid sarcoma as a tumour comprising of myeloid blasts with or without maturation occurring at an anatomical site other than the bm . radiologically the tumor is hypointense to isointense on both t1-weighted and t2-weighted images in relation to gray matter with marked homogeneous enhancement following contrast administration . the signal intensity of the tumor on the t2-weighted images was due to high levels of mpo , an iron - containing enzyme normally found in white blood cells . identification of tumor involvement in bm has also been reported on mri , and this finding may suggest the diagnosis of a myeloid sarcoma . even though the tumor can occur in any part of the body - skin , lymph node , gastrointestinal tract and testis are more frequently involved . in less than 10% of cases a myeloid sarcoma is most commonly composed of myeloblasts with or without features of neutrophilic maturation . on immunohistochemistry cd68/kp1 is the most commonly expressed marker , followed by mpo , cd117 , cd68/pg - m1 , lysozyme , and cd34 . the five types are ( a ) immature granulocytic sarcoma , ( b ) differentiated granulocytic sarcoma , ( c ) monoblastic sarcoma , ( d ) monocytic sarcoma , and ( e ) myelomonocytic sarcoma . the chromosomal abnormalities detected were monosomy 7 , trisomy 8 , trisomy 4 , and monosomy 16 . ms share morphological features similar to non - hodgkins lymphoma and both express certain markers , such as cd43 and cd45 . the diagnosis of myeloid sarcoma is confirmed by the results of cytochemical and immunophenotypic analyses . these aid the diagnosis of myeloid sarcoma and differentiate it from the lymphoblastic lymphoma , burkitt lymphoma and diffuse large b - cell lymphoma . in our study , b - cell and t - cell lymphomas were excluded by negative stains for cd20 , and cd3 , respectively . negative staining for desmin ruled out the possibility of rhabdomyosarcoma and cd99 negativity ruled out ewings sarcoma . the current recommended treatment for patients with isolated ms is the same conventional acute myeloid leukemia ( aml ) chemotherapeutic protocol . there is no evidence at present that adding radiotherapy has positive effect on the survival compared to chemotherapy alone . there is no concrete evidence on the role of hematopoietic stem cell transplantation in patients with ms . few case reports of intracranial myeloid sarcoma in patients with leukemia or spinal lesions in nonleukemic patients are available . it is uncommon to see myeloid sarcoma presenting as an intracranial space occupying lesion without features of systemic aml . presented a case of multiple skull base chloromas [ table 1 ] . the case reports previously described are depicted in the table 1 below . in addition , pileri et al . reported 3.25% of cases of ms involving central nervous system in their series of 92 patients . published cases of primary intracranial myeloid sarcomas without progression to leukemia in the follow - up period ms is a relatively uncommon intracranial mass lesion and the workup for secondary lesions is mandatory . these patients need regular follow - up to watch for progression of the tumor to systemic leukemia , intracranial recurrences and new lesions in spine . it is also important to give adequate counselling to the patient to look for any new neurological symptoms or deficits that prompt to repeat mr brain or spine as well .
intracranial occurrence of myeloid sarcoma without any evidence of systemic hematological disorder is uncommon . 
 we report the case of a 17-year - old girl who presented with features of raised intracranial pressure and paraparesis of short duration . 
 magnetic resonance imaging showed a 6 cm bilateral middle 1/3rd para sagittal contrast enhancing extra - axial mass with mass effect . 
 the tumor was subtotally excised . 
 histology and immunohistochemistry proved to be a myelosarcoma . 
 further evaluation done with peripheral blood smear and bone marrow biopsy ruled out the possibility of leukemia or myeloproliferative disorder . she was referred for chemotherapy and clinically showed improvement after 6 months of follow - up . 
 authors report a case of intracranial myelosarcoma which closely resembled meningioma both radiologically and in intraoperative morphological appearance . 
 authors discuss in detail the radiological and histological features of myelosarcoma along with differential diagnoses and treatment options .