many factors have been implicated in the etiology of gm : microbial infection , including corynebacterium , actinomycetes , and fungal infections ; hyperprolactinemia and hormone imbalances ; trauma and chemical stimulation ; contraceptive use ; and mammary duct blockade . when the disease can not be attributed to any of the aforementioned factors , it is termed idiopathic granulomatous mastitis ( igm ) . to date the clinical management often starts with tests to eliminate microbial infection and , when microbial infection can be ruled out , long - term oral steroid treatment or surgery is administered . although many patients prefer breast - preserving treatment to surgery , systemic steroid treatments can have severe side effects and may not be suitable for patients with diabetes , glaucoma , heart disease , hypertension , or obesity . more importantly , as the recurrence rate of patients who undergo surgical resection is much lower than that of patients who undergo nonsurgical treatment , it has been suggested that surgery is more effective in preventing recurrence . most studies to date have focused on the diagnosis and treatment of igm ; however , little is reported on the management of gm cases with well - defined causes . here , we describe a case of trauma - induced gm that was treated solely by surgery . we hope that the information presented herein will provide further insights into the underlying mechanisms of gm and help improve the clinical management of similar cases . a 30-year - old woman presented with a 3-month history of a painful mass and a 1-month history of skin ulceration on her left breast . she had been pregnant once and delivered a son 18 months before the symptoms developed . her left breast had been kicked by her son , after which a breast mass that measured approximately 4  4 cm in diameter developed . initially , the patient developed pain in the left breast with progressive growth of the mass . before being admitted to our hospital , she was initially treated with penicillin and cephalosporin intravenously , and she took oral and topical chinese herbal medicines for 2 weeks previously . none of these treatments stopped the growth of the breast mass or alleviated her pain . meanwhile , she developed other symptoms , including skin ulceration of the left breast , nodular erythema on both her shins , and swelling and pain in both knees and ankle area , which made walking without support difficult . at the time of hospital admission , the patient was afebrile ( temperature , 36.3c ) and in apparent good general condition . she complained of pain accompanied with tenderness in the left breast . upon examination by a specialist , a hard mass measuring 10  13 cm with an ill - defined boundary was palpable in the left breast , which also had nipple retraction . the breast mass occupied almost the entire left breast and was connected to the ulcerated skin but not to the chest wall . the patient showed symptoms of an autoimmune disease : moderate pitting edema in the lower limbs ; swelling and tenderness in both knees and the ankle area ; multiple erythematous nodules on both shins and around the ankle area ; and tenderness in the erythematous area . consistent with diagnosis by palpation , doppler ultrasound examination of the left breast revealed a diffuse thickening of the mammary gland [ figure 1 ] , and mammography revealed a heterogeneously dense region with no sign of calcification in the left breast [ figure 2 ] . magnetic resonance imaging ( mri ) was also performed on both breasts and demonstrated evident asymmetry in the appearance of the breasts and ill - defined margin of the left mammary gland [ figure 3 ] . consistent with the patient 's lack of response to antibiotic treatment , there was no evidence of bacterial growth in the ulceration exudate in culture , and we did not detect any microbes in the smear test . a diffuse thickening was detected in the mammary gland , and the thickest hyperechogenic region measured 2.2 cm in diameter . the echogenicity in the left breast was heterogeneous with an irregular anechoic structure in the 5 oclock position , penetrating the fat pad and reaching beneath the skin mammogram of the right ( a ) and left ( b ) breasts , craniocaudal view . mammogram of the right ( a ) and left ( b ) breasts , mediolateral oblique view . a heterogeneously dense region measuring 46  68 mm was observed in the left breast . multiple axillary lymph nodes in the left armpit were swollen and enlarged contrast - enhanced magnetic resonance imaging of both breasts . l indicates left side the right breast appeared to be normal . in the left breast blood tests suggested that the patient had leukocytosis ( white blood cells : 13.25  10/l ; neutrophils : 10.60  10/l ; lymphocytes : 1.89  10/l ; eosinophils : 0.01  10/l ; and basophils : 0.02  10/l ) without anemia or thrombocytopenia ( hemoglobin : 114 g / l and platelet count 460  10/l ) . her rheumatoid factor level ( 20.1 iu / ml ) was slightly higher than normal ( < 20 iu / ml ) , and her c - reactive protein ( 5.11 mg / dl ) was significantly higher than normal ( < 0.8 mg / dl ) . the levels of autoimmune antibodies , such as antistreptolysin o , anticyclic citrulline peptide , immunoglobulin ( ig ) g , iga , and igm , were all within the normal range and the levels of both perinuclear antineutrophil cytoplasmic antibody ( panca ) and cytoplasmic antineutrophil antibody ( canca ) were below the detection limit . upon admission , the ulcerated area was cleaned and the abscess was drained . however , despite these treatments , her condition did not improve . pathological examination on fine needle biopsy of the breast mass revealed the presence of a large number of neutrophils , lymphocytes , and plasma cells in the stroma of the left mammary gland . in addition , there was infiltration by multinucleated giant cells and the formation of small blood vessels [ figure 4 ] . hematoxylin and eosin staining of the surgical specimen ( 200 ) . infiltration of neutrophils , lymphocytes , and multinuclear cells are present in the stroma . the arrows show multinucleated giant cells oral steroids were offered as a treatment but rejected by the patient because of her concerns about adverse side effects . to debulk the mass , we performed abscess drainage , after which the patient developed increased joint pain and nodular erythema . upon the patient 's request , her breast and joint pain resolved , joint swelling and nodular erythema disappeared , and she was discharged 6 days after the surgery . to date , the patient has been followed - up for 11 months , and no recurrence has occurred . at the time of hospital admission , the patient was afebrile ( temperature , 36.3c ) and in apparent good general condition . she complained of pain accompanied with tenderness in the left breast . upon examination by a specialist , a hard mass measuring 10  13 cm with an ill - defined boundary was palpable in the left breast , which also had nipple retraction . the breast mass occupied almost the entire left breast and was connected to the ulcerated skin but not to the chest wall . the patient showed symptoms of an autoimmune disease : moderate pitting edema in the lower limbs ; swelling and tenderness in both knees and the ankle area ; multiple erythematous nodules on both shins and around the ankle area ; and tenderness in the erythematous area . consistent with diagnosis by palpation , doppler ultrasound examination of the left breast revealed a diffuse thickening of the mammary gland [ figure 1 ] , and mammography revealed a heterogeneously dense region with no sign of calcification in the left breast [ figure 2 ] . magnetic resonance imaging ( mri ) was also performed on both breasts and demonstrated evident asymmetry in the appearance of the breasts and ill - defined margin of the left mammary gland [ figure 3 ] . consistent with the patient 's lack of response to antibiotic treatment , there was no evidence of bacterial growth in the ulceration exudate in culture , and we did not detect any microbes in the smear test . a diffuse thickening was detected in the mammary gland , and the thickest hyperechogenic region measured 2.2 cm in diameter . the echogenicity in the left breast was heterogeneous with an irregular anechoic structure in the 5 oclock position , penetrating the fat pad and reaching beneath the skin mammogram of the right ( a ) and left ( b ) breasts , craniocaudal view . mammogram of the right ( a ) and left ( b ) breasts , mediolateral oblique view . a heterogeneously dense region measuring 46  68 mm was observed in the left breast . multiple axillary lymph nodes in the left armpit were swollen and enlarged contrast - enhanced magnetic resonance imaging of both breasts . l indicates left side the right breast appeared to be normal . in the left breast , there was a segmental enhancement of signal intensity in the mammary gland . blood tests suggested that the patient had leukocytosis ( white blood cells : 13.25  10/l ; neutrophils : 10.60  10/l ; lymphocytes : 1.89  10/l ; eosinophils : 0.01  10/l ; and basophils : 0.02  10/l ) without anemia or thrombocytopenia ( hemoglobin : 114 g / l and platelet count 460  10/l ) . her rheumatoid factor level ( 20.1 iu / ml ) was slightly higher than normal ( < 20 iu / ml ) , and her c - reactive protein ( 5.11 mg / dl ) was significantly higher than normal ( < 0.8 mg / dl ) . the levels of autoimmune antibodies , such as antistreptolysin o , anticyclic citrulline peptide , immunoglobulin ( ig ) g , iga , and igm , were all within the normal range and the levels of both perinuclear antineutrophil cytoplasmic antibody ( panca ) and cytoplasmic antineutrophil antibody ( canca ) were below the detection limit . the ulcerated area was cleaned and the abscess was drained . however , despite these treatments , her condition did not improve . pathological examination on fine needle biopsy of the breast mass revealed the presence of a large number of neutrophils , lymphocytes , and plasma cells in the stroma of the left mammary gland . in addition , there was infiltration by multinucleated giant cells and the formation of small blood vessels [ figure 4 ] . the arrows show multinucleated giant cells oral steroids were offered as a treatment but rejected by the patient because of her concerns about adverse side effects . to debulk the mass , we performed abscess drainage , after which the patient developed increased joint pain and nodular erythema . upon the patient 's request , her breast and joint pain resolved , joint swelling and nodular erythema disappeared , and she was discharged 6 days after the surgery . to date , the patient has been followed - up for 11 months , and no recurrence has occurred . in the case presented here , the patient 's left breast was traumatized shortly before the development of gm . the temporal relationship between these two events and the lack of other known diseases at the time of diagnosis suggested that trauma was the trigger for gm in this case . two months after the breast mass had occurred , the patient developed swelling and tenderness in her joints and nodular erythema on her shins , all of which are symptoms of autoimmune diseases . as she had no autoimmune disease prior to the development of gm , and her autoimmune symptoms disappeared soon after the removal the breast mass , we suspected that the autoimmune responses were probably secondary symptoms of gm . as the patient did not receive treatment with anti - inflammatory agents during the initial disease phase , the autoimmune response induced further damage to the breast tissue , which in turn aggravated the inflammation . after clinical pathological examination revealed the presence of leukocytosis , we recommended that oral steroids be given to the patient . however , her brother had been treated with oral steroids and had developed several side effects ; therefore , she rejected the treatment plan and insisted on surgery . respecting the patient 's choice and considering that surgery was a good option for her condition , we surgically removed the affected mammary tissue but preserved the nipple and the upper - quadrant areola . the removal of the diseased breast mass led to a complete resolution of her autoimmune symptoms , which further supported the notion that the autoimmune responses were secondary symptoms of gm in this patient . during the subsequent follow - up period of 11 months further follow - up examinations will be conducted to assess whether recurrent gm will develop . although treatment with systemic steroids has been reported to be successful in some patients with gm , adverse side effects have been reported after long - term steroid treatment . unlike most reports of gm with symptoms of inflammation , no steroid treatment was used in this case , and the patient has not relapsed to date . therefore , surgery can be considered in gm cases that have systemic inflammation but are not treatable with steroids .
granulomatous mastitis ( gm ) is a rare breast disease with unknown etiology . 
 clinical management strategies for gm include surgery , antibiotics , and steroid treatments . 
 as patients with gm often respond to steroids , gm is thought to be an autoimmune disease . 
 here we describe a case of trauma - induced gm that presented as autoimmune disease but was successfully treated by surgery without steroids . 
 the patient showed no sign of recurrence for 11 months . 
 this case provides useful information on both the underlying mechanisms and clinical management of gm .