Table 2.

Workup of granulomatous breast disease.

Diagnosis	Tests to consider
Sarcoidosis	ACE level, chest radiograph, and serum calcium
Tuberculosis	PPD, MTB QuantiFERON Gold, chest radiograph, acid fast tissue stain, and mycobacterial tissue culture
Infectious mastitis	Tissue culture for bacteria, fungi, and atypical mycobacteria; Gram stain, fungal stain, acid fast stain; fungal serologies if fungal infection suspected in endemic areas
Wegener's granulomatosis	ANCA antibody, PR3 antibody, CRP, creatinine, UA, and chest radiograph
Giant cell arteritis	ESR/CRP
Takayasu's arteritis	ESR/CRP, CBC (may show anemia or elevated platelets), CT chest angiography with contrast, or CT abdomen angiography with contrast
Churg–Strauss syndrome	CBC with differential to evaluate for eosinophilia, histopathology of affected organ, and electromyelogram to diagnosis peripheral neuropathy or mononeuritis multiplex
Crohn's disease	Colonoscopy with ileal exam, small bowel imaging with CT or MR enterography, evidence of extraintestinal signs (erythema nodosum, pyoderma gangrenosum, episcleritis, scleritis, anterior uveitis or iritis, and primary sclerosing cholangitis)
IgG4-RD mastitis	Histopathology demonstrating classic findings; serum IgG4 levels not needed for diagnosis but can be supportive of diagnosis
Diabetic mastopathy	Characteristic histopathology in a patient with type I diabetes
Breast cancer	Histopathology, ideally from core needle biopsy