primary lymphoma of the parotid gland is an uncommon entity . predominantly ( 84 - 97% ) parotid lymphomas are
non - hodgkin lymphomas ( nhl ) and most of them are of b - cell origin . there may be coexisting lymphadenopathy of the cervical region . however , to categorize them as a primary from the parotid , the first clinical manifestation should arise in the parotid gland .
we report a case of primary nhl of the parotid gland in a 61-year - old male that was diagnosed on fine needle aspiration cytology ( fnac ) with further histological confirmation .
a 61-year - old male presented with a painless swelling in the right parotid region for the last 1 year and right sided cervical swelling for the last 3 months . on examination , a mass of 5 cm  5 cm was identified in the parotid region .
in addition , the patient had an enlarged right sided level v cervical lymph node .
hematological investigations were within normal limits ( hemoglobin  11.8 gm / dl , total leukocyte count  6000/cumm and a differential count of 66% neutrophils , 28% lymphocytes , 4% eosinophils and 2% monocytes , platelet count  1.6 lakhs / cumm ) .
his erythrocyte sedimentation rate was elevated with 58 mm at the end of the first hour .
contrast - enhanced computed tomography ( cect ) revealed a lobulated mass of 7 cm  5 cm  2.5 cm arising from the deep lobe of the parotid .
fnac was advised from both the parotid swelling and the enlarged right sided level v cervical lymph node .
smears were moderately cellular and comprised of large atypical lymphoid cells with high n : c ratio , irregular nuclear contour , vesicular chromatin , and prominent nucleoli and scanty agranular cytoplasm .
the background showed lymphoglandular bodies alongwith normal - appearing salivary gland acini and ducts [ figure 1a ] .
subsequently , immunocytochemistry ( icc ) was performed on the papanicolaou - stained smears without destaining .
these cells were positive for leukocyte common antigen ( lca ) , cluster of differentiation ( cd ) 20 ( inset ) and negative for cd3 and cytokeratin . in view of the icc findings
, a diagnosis of high grade nhl favoring diffuse large b - cell lymphoma ( dlbcl ) was offered .
( a ) fnac of the parotid mass shows moderately cellular smears comprising of large atypical cells with scant cytoplasm , irregular nuclei , vesicular chromatin , and prominent nucleoli .
background shows normalappearing salivary gland acini and ducts ( arrow ) ( mgg , 400 ) .
inset : b - cell marker ( cd20 ) positivity of the tumor cells ( icc , 100 ) ( b ) cervical lymph node fnac shows similar cytomorphology ( mgg , 100 ) fnac from the cervical lymph node showed similar cytomorphology [ figure 1b ] . in view of the above findings , a diagnosis of high grade b - cell nhl favoring dlbcl involving the right parotid gland with secondary involvement of the level v cervical lymph node was made .
excision biopsy of the cervical lymph node revealed diffuse effacement of the architecture with sheets of atypical lymphoid cells with vesicular chromatin and scanty cytoplasm .
based on the above histological and ihc findings , a diagnosis of dlbcl was made .
correlating with the clinical history and radiological findings , final diagnosis of a primary dlbcl of the right parotid gland with secondary involvement of level v cervical lymph node was made .
the patient was treated with six cycles of rituximab - cyclophosphomide - hydroxydoxorubicin - oncovin - prednisolone ( r - chop ) chemotherapy .
malignant lymphoma of the parotid gland is relatively rare and constitutes about 4 - 5% of extranodal lymphomas , and 1 - 4% of all parotid tumors .
facial nerve paresis and associated cervical lymphadenopathy may be a feature as well . in the present case
they may be associated with autoimmune diseases such as sjgren 's syndrome . in the present case ,
the lymphoma may originate from the intraparotid lymph nodes or from the parenchyma ( mucosa - associated lymphoid tissue [ malt ] ) or both . in view of this ,
lymphoma primarily affecting the parotid gland  to refer to lymphoma affecting the parotid region .
the differentials of malt lymphoma are lymphoepithelial sialadenitis ( lesa ) and warthin 's tumor .
the cytology of lesa reveals a mixture of acinar cells , epithelial , and myoepithelial cells admixed with polymorphous lymphoid cell population .
warthin 's tumor is considered a benign primary parotid gland neoplasm that is composed of a mixture of oncocytic cells , basal cells , and stroma that contains numerous lymphocytes usually arranged in papillary and cystic structures .
by contrast , the diagnosis of non - malt high grade lymphomas is usually straightforward , as they have overt cytological atypia .
the criteria for primary parotid lymphoma , as suggested by hyman and wolff , include the first clinical manifestation in the parotid gland , histologically involving the parotid gland parenchyma and malignant nature of the lymphoid infiltrate . in the present case ,
the parotid swelling developed earlier than the cervical lymph node and the parenchyma was infiltrated by malignant lymphoid cells , meeting all the criteria as suggested by hyman and wolf for primary lymphoma of the parotid .
lymphoma of the salivary gland is highly chemo - radiosensitive and , therefore , a timely diagnosis is important .
moreover , surgical management of parotid lymphoma patients carries a high risk of morbidity due to infiltrative nature of the neoplasm .
the role of fnac thus becomes important in such a setting for an early definitive diagnosis .
 primary lymphoma of the parotid gland is relatively rare and constitutes about 4 - 5% of extranodal lymphomas . 
 the majority of them is non - hodgkin lymphoma ( nhl ) and is b cell in nature . 
 we report a case of primary diffuse large b - cell lymphoma ( dlbcl ) of the parotid gland in an elderly male . 
 the case was diagnosed on fine needle aspiration cytology ( fnac ) of the right parotid gland as high grade b - cell nhl and confirmed on histopathology as dlbcl . in correlation with the clinicoradiological findings 
 , the case was diagnosed as primary parotid dlbcl . 
 the case highlights the role of fnac as a timely and useful diagnostic tool . 