Granulomatous lobular mastitis (GLM) is a chronic inflammatory disease of the breast. If an underlying cause is not identified after a complete workup then it is termed idiopathic.

Conditions associated with granulomatous mastitis:

(1) infection (Mycobacteria, deep fungal, actinomycosis, Corynebacteria, filarial, cat scratch)

(2) autoimmune disorder (Wegener’s, giant cell arteritis, SLE)

(3) duct ectasia and/or milk leakage

(4) diabetes mellitus

(5) sarcoidosis

(6) fat necrosis

(7) alpha-1 antitrypsin deficiency

(8) foreign body reaction

(9) idiopathic (if all else is negative)


Clinical features:

(1) It usually occurs in a young woman within a few years of a pregnancy.

(2) There is a unilateral, extra-areolar lump that is typically tender to palpation.

(3) The mass may range from 1 to 8 cm in diameter.

(4) The mass may be described as firm or hard.

(5) variable nipple retraction

(6) variable sinus formation

(7) variable ipsilateral axillary lymphadenopathy


Changes on imaging studies may mimic breast carcinoma.


Histologic features:

(1) The primary lesion is a noncaseating granulomas with subacute inflammation centered on the breast lobules.

(2) Extensive lesions may coallesce into an abscess.

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