granulocytic sarcoma ( gs ) , also known as chloroma , extramedullary myeloid tumor , myeloid sarcoma , leukocytic sarcoma and myelosarcoma is defined as an extramedullary tumor mass of immature cells of myeloid lineage [ 1 - 3 ] . was reported by burn in 1811 . in 1853 , king used the term chloroma , because of its greenish color , to refer to gs whose tumoral cells produced myeloperoxidase with exposure to the air , but because this tumor is not always green , granulocytic sarcoma is a more appropriate term . in the head and neck areas , gs is often seen in the soft tissues of orbit , nasal cavity and paranasal sinuses , but it can also appear in any location throughout the body including the skin , breasts , gastrointestinal , genitourinary , respiratory tracts , peripheral nerves and lymph nodes [ 7 - 10 ] . there is a female predilection and most cases occur in childhood . although intensive chemotherapy is the main treatment choice for gs , the related death and relapse rates are the essential factors for prediction of prognosis of gs [ 1 , 2 , 12 ] . recently , improving leukemia stem cell biology understanding and considering interaction of the stroma and the host response , may introduce more markers which show the value of result prediction and guide therapy ; for example , cd47 which is highly expressed on leukemic stem cells compared to the normal hematopoietic stem cells and microrna expression patterns are additional markers for predicting worse survival rate . some degrees of improvement can be achieved after surgery and radiotherapy , but the prognosis of gs is poor and most patients die within months . it seems that only 2 cases have been reported in the literature with this appearance [ 14 , 15 ] . a 45-year - old male referred to shahid beheshti maxillofacial pathology department with a two year history of generalized proliferative gingival maxillary lesions with palatal right side swelling and mandibular labially gingival lesions ( figure 1 ) . the lesions were asymptomatic , without any bleeding or purulent discharge . the right submandibular lymph node was palpable and the patient noticed this swelling after the extraction of the third molar one month prior to his visit to our department . the gingivally lesions were red and soft with irregular surfaces , and the palatal swelling had a purple - gray appearance with intact overlying mucosa ( figure 2 ) . laboratory test results were normal , so the patient s diagnosis was stated as inflammatory and reactive hyperplastic lesions . tissues needed for histopathologic evaluation were obtained from the gingivectomy of gingivally proliferative masses and with a full thickness flap from the palatal swelling . soft tissue specimens were fixed in 10% neutral buffered formalin and embedded in paraffin blocks . for standard pathological examination , the sections were prepared with h&e stain . the slides of both gingival and palatal specimens showed a dense cellular infiltration under the epithelial layer in deeper portions . the cells were mononuclear which showed pleomorphism with moderately amount of cytoplasm and round to oval nucleus with prominent nucleoli . therefore , a series of differential diagnosis such as large cell lymphoma , plasmacytoma , poorly differentiated carcinoma and lymphoblastic leukemia was suggested ( figure 3 - 4 ) . for the final diagnosis the tumor cells were diffusely positive with antibodies against lca , negative with cd20 , cd3 and cd79a and positive with c - kit . therefore , according to the ihc results in combination with morphological features , the final diagnosis was made as granulocytic sarcoma . bone marrow biopsy and bone marrow aspiration were negative for malignant cells , and the laboratory tests revealed only an increase in the monocyte population . the treatment protocol was 5 courses of induction chemotherapy with cytarabine , idarubici and doxorubicin and adjuvant whole brain radiotherapy . during the chemotherapy , the patient had neutropenia and thrombocytopenia . although we tried to manage the complications , the clinical outcome became worse , and the patient died after a heart attack 10 months post diagnosis . , dock found an association between granulocytic sarcoma and leukemia for the first time [ 16 , 17 ] . clinically granulocytic sarcoma may occur in three categories : in a patient previously known to have acute myeloid leukemia ( aml ) ; as a sign of blast transformation in a patient with chronic myeloid leukemia ( cml ) , or other chronic myeloproliferative disorders ; in a patient who was previously well . nearly 40 cases of intraoral gs have been reported from 1883 up to now . involvement of oral tissue without detectable evidence of leukemic cells in peripheral blood and bone marrow was observed in 14 cases [ 6 , 19 - 30 ] ; and only two patients had both jaws involvement [ 13 , 14 ] . the highly invasive and aggressive clinical behavior of gs might be explained by the findings of kabayashi et al . [ 31 , 32 ] . in one study , they found the capability of gs - derived cell line to bind both the bone marrow and the skin fibroblast , which resulted in the formation of extramedulary myeloid tumor . gingival tissues due to expression of endothelial adhesion molecules , which may increase leukocyte infiltration , are more susceptible to leukemic cell invasion [ 7 , 8 , 16 ] . however , the association of aml with gingival occurrence of gs is extremely rare . diagnosis of gs in a patient with known myeloid leukemia is not difficult . however , when presented as an isolated entity , like our case , it may be clinically misdiagnosed as an inflammatory lesion such a pyogenic granuloma ( pg ) , peripheral giant cell granuloma ( pgcg ) , gingival or periodontal abscess . this may lead to surgical procedures such as gingivectomy ; however , the management of gs is different . positive staining for cd45 is needed to confirm the hematological origin . in the next step , one or more myeloid markers such as myeloperoxidase , lysozyme , cd13 , cd14 , cd33 , cd34 , cd68 or c - kit should be positive . in the present case , tumoral cells were stained positively with c - kit . in patients without evidence of leukemia , antileukemic chemotherapy regime upon the initial diagnosis of gs is associated with a lower probability of aml development , but the overall survival rate of patients with intraoral gs is poor . according to the literature , only four patients survived more than 3 years . therefore , regular therapies such as treatment with combining growth factors and pharmacologic differentiating agents , and assessing appropriate allograft procedures in the remission period   may be of importance . because gs may be seen before the diagnosis of leukemia , or it could be presented without bone marrow involvement ( the same as our case ) , it is advisable to include gs in the differential diagnosis of severe gingival hyperplasia . because gs may be seen before the diagnosis of leukemia , or it could be presented without bone marrow involvement ( the same as our case ) , it is advisable to include gs in the differential diagnosis of severe gingival hyperplasia .