this high - grade lymphoma can be subdivided into endemic , sporadic and immunodeficiency - associated forms with incidence of 50 - 100/million , 2 - 3/million and 6/1,000 acquired immune deficiency syndrome cases in order . the sporadic form usually involves the abdomen or bone marrow and seldom ( < 25% ) involves the head and neck . burkitt 's lymphoma in the head and neck usually presents as lymphadenopathy , whereas primary involvement of the nasal cavity and paranasal sinuses is uncommon . in paranasal burkitt 's lymphoma , maxillary sinus is most commonly involved and spheno - ethmoidal sinuses are less commonly involved . we describe here two cases of burkitt 's lymphoma in the nasal cavity and paranasal sinuses . a 25-year - old man presented with a 2-month history of nasal obstruction and right facial pain . a physical examination revealed a pinkish , irregularly shaped mass in both nasal cavities ( fig . 1 ) . a computed tomography ( ct ) showed an enhanced mass filling both ethmoid sinuses , the right nasal cavity and nasopharynx , with secondary destruction of the ethmoidal roof , both medial orbital walls and the anterior wall of the sphenoid sinuses . pathologic evaluation showed " starry - sky " pattern of tightly packed , medium sized uniform lymphoid cells interspersed with large pale histiocytes . in immunohistochemical staining , cells were positive for cd10 , cd20 , and bcl-6 , and negative for cd3 , cd5 , and bcl-2 . ninety percent of the cells were positive for ki-67 antigen . the serum was negative for epstein - barr virus ( ebv ) and human immunodeficiency virus ( hiv ) . positron - emission tomography ( pet ) showed lymphoid invasion of the sphenoid , mandible , both humeri and the right proximal femur . examination of cerebrospinal fluid ( csf ) and bone marrow ( bm ) showed normal pathological and chromosomal findings . he was initiated on chemotherapy , consisting of cyclophosphamide , vincristine , methotrexate , ifosfamide , etoposide , and cytarabine . after three cycles five months after the end of chemotherapy , there was no evidence of recurrence on pet . a 44-year - old man presented with a 2-month history of right nasal obstruction . the patient had underwent functional endoscopic sinus surgery , after failure of 2 month medical therapy at other institution . since frozen sections during the sinus surgery revealed malignant cells , he was referred to our hospital . magnetic resonance imaging ( mri ) showed a large mass infiltrating the posterior aspect of the right maxillary sinus with extension into the posterior portion of the bilateral nasal cavity , nasopharynx , and right parapharyngeal , masticator and buccal spaces ( fig . biopsy slides from the first hospital revealed a typical " starry - sky " pattern . in immunohistochemical staining , cells were positive for cd10 and cd20 and negative for cd3 . chest x - rays , abdominopelvic ct and bone scan showed no evidence of metastasis . he was initiated on chemotherapy , consisting of cyclophosphamide , vincristine , doxorubicin , methotrexate , ifosfamide , etoposide , and cytarabine . nine months after chemotherapy , follow - up mri showed no evidence of remnant tumor ( fig . a 25-year - old man presented with a 2-month history of nasal obstruction and right facial pain . a physical examination revealed a pinkish , irregularly shaped mass in both nasal cavities ( fig . 1 ) . a computed tomography ( ct ) showed an enhanced mass filling both ethmoid sinuses , the right nasal cavity and nasopharynx , with secondary destruction of the ethmoidal roof , both medial orbital walls and the anterior wall of the sphenoid sinuses . pathologic evaluation showed " starry - sky " pattern of tightly packed , medium sized uniform lymphoid cells interspersed with large pale histiocytes . in immunohistochemical staining , cells were positive for cd10 , cd20 , and bcl-6 , and negative for cd3 , cd5 , and bcl-2 . ninety percent of the cells were positive for ki-67 antigen . the serum was negative for epstein - barr virus ( ebv ) and human immunodeficiency virus ( hiv ) . positron - emission tomography ( pet ) showed lymphoid invasion of the sphenoid , mandible , both humeri and the right proximal femur . examination of cerebrospinal fluid ( csf ) and bone marrow ( bm ) showed normal pathological and chromosomal findings . he was initiated on chemotherapy , consisting of cyclophosphamide , vincristine , methotrexate , ifosfamide , etoposide , and cytarabine . after three cycles five months after the end of chemotherapy , there was no evidence of recurrence on pet . the patient had underwent functional endoscopic sinus surgery , after failure of 2 month medical therapy at other institution . since frozen sections during the sinus surgery revealed malignant cells , he was referred to our hospital . magnetic resonance imaging ( mri ) showed a large mass infiltrating the posterior aspect of the right maxillary sinus with extension into the posterior portion of the bilateral nasal cavity , nasopharynx , and right parapharyngeal , masticator and buccal spaces ( fig . biopsy slides from the first hospital revealed a typical " starry - sky " pattern . in immunohistochemical staining , cells were positive for cd10 and cd20 and negative for cd3 . chest x - rays , abdominopelvic ct and bone scan showed no evidence of metastasis . he was initiated on chemotherapy , consisting of cyclophosphamide , vincristine , doxorubicin , methotrexate , ifosfamide , etoposide , and cytarabine . nine months after chemotherapy , follow - up mri showed no evidence of remnant tumor ( fig . the most common symptom of sinonasal lymphomas is nasal obstruction ; others are headache , rhinorrhea and facial pain , mostly consistent with chronic rhinosinusitis . thus , it can be easily confused with paranasal sinusitis , polypoid disease or other tumorous conditions . therefore , in the early stages , burkitt 's lymphomas in this region may be misdiagnosed as other diseases . our second patient was misdiagnosed with rhinosinusitis and underwent medical treatment for 2 months followed by endoscopic sinus surgery . early diagnosis and prompt chemotherapy is important in burkitt 's lymphoma because it is one of the fastest growing tumors , with a cell doubling time of only 24 to 48 hours . if treatment is delayed , burkitt 's lymphoma can spread to other parts of the body , leading to poor prognosis . if burkitt 's lymphoma involves the paranasal sinuses , it can cause facial deformity . in patient 2 , the lesion in the right maxillary sinus extended to the right parapharyngeal and masticator space during the period of misdiagnosis . in diagnostic workup , not only endoscopic biopsies but also bm / csf analysis and complete laboratory testing are necessary . ct and mri can help determine the extent of the primary disease . the bm is involved in 30%-38% and the central nervous system ( cns ) in 13%-17% of adults with burkitt 's lymphoma . generally , ann arbor staging system has been used in both hodgkin 's and non - hodgkin lymphoma , and burkitt 's lymphoma could be classified by same staging system . but , there is separate staging system for burkitt ' lymphoma and patton et al . developed staging system particularly for sporadic type . according to the staging system by patton et al . , first patient could be classified as stage iii and second patient could be classified as stage ii . immunophenotypically , burkitt 's lymphoma expresses b - cell lineage markers , including cd19 , cd20 , cd22 , cd74 , and cd79a , and coexpressing cd10 , bcl-6 , cd43 , and p53 , but not cd5 , cd23 , bcl-2 , cd138 or tdt . as one of the fastest growing tumors with a high mitotic index , burkitt 's lymphoma is highly sensitive to cytotoxic agents . thus , the primary therapeutic modality is complex chemotherapy , including cyclophosphamide , vincristine , methotrexate and prednisone . the currently used regimens for burkitt 's lymphoma limited to the head and neck region have yielded long - term survival rates of 90% . patients with old age , advanced staged disease , bulky mass , high lactate dehydrogenase level , and cns or marrow involvement , are known to have poor prognosis . both of our patients showed very good responses to chemotherapy , with no evidence of recurrence . generally , regional radiotherapy or surgical treatment increases morbidity without affecting survival , although surgical debulking and radiotherapy to diminish tumor volume have been reported . in conclusion , burkitt 's lymphoma in the nasal cavity and paranasal sinuses is rare but needs prompt diagnosis .
burkitt 's lymphoma is a highly aggressive small b - cell lymphoma . 
 the treatment of choice is complex chemotherapy . as a rare tumor in the head and neck area , 
 burkitt 's lymphoma usually involves cervical lymph nodes , and only fewer than 25% of cases involves extranodal regions . 
 involvement of the paranasal sinuses has been reported in only 14 cases in the past century . 
 we describe here two patients with rare , sporadic , american type burkitt 's lymphoma involving the nasal cavity and paranasal sinuses manifesting nasal obstruction . 
 we also review clinical and histological features of burkitt 's lymphoma .