Abstract:

Idiopathic granulomatous lobular mastitis, which clinically and radiologically mimics breast cancer, is a rare chronic inflammatory breast lesion of unknown etiology. It generally engenders a unilateral mass, commonly in young women. Definitive diagnosis is given by histopathologic examination after exclusion of other causes of granulomatous mastitis. Case: A 39-year-old female patient who presented at the clinic complaining from painful mass in the breast and brown-yellow nipple discharge. Physical examination showed a 4x5 cm mass with lobular borders at the lower exterior quadrant. Bilateral mammography reported poorly demarcated opacity of 3x3 cm at the lower middle of the left breast and breast ultrasound showed a heterogeneous hypoechoic mass, surrounded by echogenic foci, measuring about 35x25 mm and bordering the lobule at the lower middle of the left breast. When radiological examination was seen to support breast carcinoma, FNAB was conducted and evaluated as acute inflammatory reaction. This was followed by histopathologic examination of the biopsy sample, by which granulomatous lobular mastitis diagnosis was given. The case who was operated on and discharged without further treatment presented again six months later complaining from pain in the same breast. Physical examination revealed solid, mobile masses measuring 3x3 cm at the lower exterior quadrant of the left breast and 2x1 cm at the exterior medial quadrant. The excised quadrants were diagnosed as granulomatous lobular mastitis.In conclusion, idiopathic granulomatous lobular mastitis is a rare breast lesion which appears as breast carcinoma clinically and in radiology. It should be noted that fistulation, breast skin-nipple retraction and axillary lymphadenopathy may occur in later stages and idiopathic granulomatous lobular mastitis should be considered in differential diagnosis.

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