Necrotising granulomatous lymphadenitis.

My mom( diabetic patient has pain in right underarm with inflammation 3 mnths bfr,so  went to breast center and did  mammogram with contrast and  the report was :1.(Necrotic right axillary lymphadenopathy, suspicious abnormality ( birads 4) , biopsy is recommended.2.masses with circumscribed margin in right breast probably benign suggested follow up after 6 mnths.3.simple cyst in left breast,retroareolar duct ectasia in right breast( benign) .Then did  USG guided fnac and the report was necrotising granulomatous lymphadenitis suggestive of tb, so done tb test( afb smear,pus stain, xray,afb stain,culture, gene xpert ) and the result was negative ,did biopsy by removing a lymph node, shows no malignancy .Dr said there were many lymph nodes and few where pus filled so checked for infection like HIV, hcv-av,hbs-ag) and the result was negative.  Nw I wnt to knw the reason for multiple lymph nodes with few pus filled.Is this anythng serious?or need to see wat kind of spclist or do any test?