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Introduction Myeloid sarcomas (MS) or granulocytic sarcomas have been associated with acute myelogenous leukemia, myelodysplastic, or myeloproliferative disorder.[12] Uncommonly, they can occur alone without peripheral blood or bone marrow (BM) evidence of leukemia.[1] MS is a neoplasm of immature granulocytes, monocytes, or both involving any extra-medullary site.[2] It can develop before, simultaneously or after the onset of systemic leukemia.[3]

r myeloproliferative disorder.[12] Uncommonly, they can occur alone without peripheral blood or bone marrow (BM) evidence of leukemia.[1] MS is a neoplasm of immature granulocytes, monocytes, or both involving any extra-medullary site.[2] It can develop before, simultaneously or after the onset of systemic leukemia.[3] Case Report 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 1/3rd para sagittal extra-axial mass. It was isointense in both T1- and T2-weighted images. It showed mass effect, perilesional edema, and contrast enhancement along the falx. 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. Spectroscopy showed high choline peak suggesting increased cell turnover [Figure 1]. Meningioma and hemangiopericytoma were considered as the main differential diagnoses on radiology. She underwent bi-parietal parasagittal craniotomy and subtotal excision leaving the tumor within the sinus. Intraoperatively dura was thickened. Tumor had attachment to convexity as well as the falx. It was firm, grayish, and moderately vascular. There was no infiltration of bone by the tumor and the bone flap was replaced back. There was no definite arachnoid plane with the surrounding normal brain. Postoperative MR showed residual tumor along and within the sinus. Postoperative period was uneventful and there was mild improvement in her weakness in both lower limbs. Tumor was sent for histopathological examination.

ne flap was replaced back. There was no definite arachnoid plane with the surrounding normal brain. Postoperative MR showed residual tumor along and within the sinus. Postoperative period was uneventful and there was mild improvement in her weakness in both lower limbs. Tumor was sent for histopathological examination. Figure 1 (a) Tumor was isointense in T2-weighted images.(b) Coronal and. (c) sagittal images showed contrast enhancement. (d) Magnetic resonance venogram showed the blockage of superior sagittal sinus in the middle. (e) Increased perfusion was seen in the perfusion-weighted image sequence. (f) The spectroscopy showed high choline peak. (g) Coronal and. (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. Prominent apoptotic bodies with mitotic activity were noted. 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]. Overall features were consistent with myeloid sarcoma. No fresh sample was available for fluorescence in situ hydridization or cytogenetics studies.

se (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]. Overall features were consistent with myeloid sarcoma. No fresh sample was available for fluorescence in situ hydridization or cytogenetics studies. Figure 2 (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) Figure 3 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 were normal. There was no evidence of systemic leukemic disorder. She was advised to take chemotherapy. Patient was put on cyclophosphamide based chemotherapy and remained asymptomatic after 6 months of follow-up.

evaluate systemic disease showed no evidence to support it. Her BM biopsy and peripheral blood smear tests were normal. There was no evidence of systemic leukemic disorder. She was advised to take chemotherapy. Patient was put on cyclophosphamide based chemotherapy and remained asymptomatic after 6 months of follow-up. Discussion Myeloid sarcoma is also called as chloroma due to its greenish hue resulting from the presence of myeloperioxidase.[4] In the cranial cavity, the MS is postulated to emerge from the BM of the skull. 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.[4] Intracranial myeloid sarcomas have been reported in both infra- and supra-tentorial locations.[5] 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.[6] 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.[34] Identification of tumor involvement in BM has also been reported on MRI, and this finding may suggest the diagnosis of a myeloid sarcoma.[5]

trast 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.[34] Identification of tumor involvement in BM has also been reported on MRI, and this finding may suggest the diagnosis of a myeloid sarcoma.[5] 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 it may occur in multiple anatomical sites.[6] A myeloid sarcoma is most commonly composed of myeloblasts with or without features of neutrophilic maturation.[67] On immunohistochemistry CD68/KP1 is the most commonly expressed marker, followed by MPO, CD117, CD68/PG-M1, lysozyme, and CD34. MS was classified into five types based on morphological and immunohistochemical analyses. The five types are (a) immature granulocytic sarcoma, (b) differentiated granulocytic sarcoma, (c) monoblastic sarcoma, (d) monocytic sarcoma, and (e) myelomonocytic sarcoma.[2] The chromosomal abnormalities detected were monosomy 7, trisomy 8, trisomy 4, and monosomy 16.[6]

phological and immunohistochemical analyses. The five types are (a) immature granulocytic sarcoma, (b) differentiated granulocytic sarcoma, (c) monoblastic sarcoma, (d) monocytic sarcoma, and (e) myelomonocytic sarcoma.[2] The chromosomal abnormalities detected were monosomy 7, trisomy 8, trisomy 4, and monosomy 16.[6] The main differential diagnosis to be considered is malignant lymphoma. MS share morphological features similar to non-Hodgkins lymphoma and both express certain markers, such as CD43 and CD45.[2] An inadequate workup may lead to confounding diagnosis. 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.[6] 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. Cytarabine has been found as a key drug in the regimen. 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.

(AML) chemotherapeutic protocol. Cytarabine has been found as a key drug in the regimen. 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[89] or spinal lesions in nonleukemic patients[1] are available. It is uncommon to see myeloid sarcoma presenting as an intracranial space occupying lesion without features of systemic AML. Widhalm et al.[11] and Qian et al.[14] presented case reports with both intracranial and intraspinal lesions. Thakar et al. presented a case of multiple skull base chloromas [Table 1].[4] 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.[15] Table 1 Published cases of primary intracranial myeloid sarcomas without progression to leukemia in the follow-up period

Few case reports of intracranial myeloid sarcoma in patients with leukemia[89] or spinal lesions in nonleukemic patients[1] are available. It is uncommon to see myeloid sarcoma presenting as an intracranial space occupying lesion without features of systemic AML. Widhalm et al.[11] and Qian et al.[14] presented case reports with both intracranial and intraspinal lesions. Thakar et al. presented a case of multiple skull base chloromas [Table 1].[4] 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.[15] Table 1 Published cases of primary intracranial myeloid sarcomas without progression to leukemia in the follow-up period Conclusion Authors report primary intracranial sarcoma where the tumor radiologically and intraoperatively resembled meningioma. This case emphasize to consider MS as a differential diagnosis for extra axial mass. Tumor may not always exhibit greenish appearance or involve the bone. MS is a relatively uncommon intracranial mass lesion and the workup for secondary lesions is mandatory. These patients should be treated along the line of AML treatment protocol with chemotherapy. 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. Financial support and sponsorship Nil.

Conclusion Authors report primary intracranial sarcoma where the tumor radiologically and intraoperatively resembled meningioma. This case emphasize to consider MS as a differential diagnosis for extra axial mass. Tumor may not always exhibit greenish appearance or involve the bone. MS is a relatively uncommon intracranial mass lesion and the workup for secondary lesions is mandatory. These patients should be treated along the line of AML treatment protocol with chemotherapy. 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. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest