Radiologic Features of IdiopathicGranulomatous MastitisZ. ACHOUR 1, H. EL MHABRECH1, A. KHELIFFI1, E. BEN SALEM1, A. HADDAD2, CH. LOUSSAIF 3, C. HAFSA1

Radiology Service, CMN Monastir Tunisia

INTRODUCTION:

Idiopathic granulomatous lobular mastitis,or

idiopathic granulomatous mastitis (IGM), is a rare

chronic inflammatory lesion of the breast that can

clinically and radiographically mimic breast

carcinoma.

purpose:

The aim of this study is to describe the radiological imaging features of IGM in order to better differentiate this disorder from breast cancer.

MATERIALS AND METHODSWe performed a retrospective analysis of the clinical

and radiographic features of 7 women with a total of

7 IGM lesions. The ages of these women ranged

between 30 and 48 years.

The chief clinical complaint was: breast mass in 4

cases and inflammatory mastitis in 3.

All patients were examined by both mammography

and sonography.

RESULTS:A 37 year-old female, gravida 6 para 3 consulted for a right breast mass A mammogram was realised and concluded to an increased density of the upper lateral quadrant of the right breast. US hypoechoic area with low decreased acoustic shadowing. The patient undrwent a surgical excision and pathology showed IGM

a

US: irregula tubular lesions

Lateral mammogram of a 34-year-old female patient with a huge idiopathic granulomatous mastitis. Note the presence of a vague increased density of the left breast in the absence of a discrete mass or suspicious micro-calcifications.

A 48 year-old female, gravida 5 para 3 consulted for a right breast mass. A mammogram was realised and concluded to an increased density of the lower lateral quadrant of the right breast. US hypoechoic mass with low decreased acoustic shadowing.

A 48 year-old female,gravida 4 para 3, was admitted to the hospital for a recurrent breast abscess. Mammography revealed an opacity of the lower medial quadrant of the right breast. US an important galactophoric ectasia with an echogenic conten. The patient undrwent a surgical excision and pathology showed IGM with multinucleated giant cell and chronic lobulitis 

Malignancy was suspected in all patients and fine needle biopss was performed in all cases cofirming the diagnosis of IGM

DISCUSSION:

Idiopathic granulomatous lobular mastitis , or idiopathic

granulomatous mastitis, is a rare chronic inflammatory lesion of the

breast that can clinically and radiographically mimic breast carcinoma.

IGM was first described by Kessler and Wolloch in 1972. This disorder

is characterized by the chronic granulomatous inflammation of lobules

without caseous necrosis IGM is of unknown origin, and its diagnosis

rests on both the demonstration of a characteristic histological pattern

and the exclusion of other possible causes of granulomatous breast

lesions.

Although the exact etiology of IGM remains unclear, associations

with autoimmune disorders, oral contraceptive use, pregnancy,

hyperprolactinemia and alpha-1-antitrypsin deficiency have been

suggested. Most studies report an average age of presentation in

the third decade of life (range 11 to 83 years) with symptoms

often developing within a few years of pregnancy. Moreover,

conflicting data exists regarding the significance of oral

contraceptive use in patients diagnosed with IGM.

The diagnosis of IGM rests on the documentation of

a characteristic histologic pattern, combined with the

exclusion of other possible causes of granulomatous

lesions of the breast.

IMAGING ASPECTS:

Mammography and ultrasonography are used mainly to rule out malignancy rather than confirming the diagnosis of IGM +++.

Mammographic features ofgranulomatous mastitis

The reported mammographic features of granulomatous

mastitis are :

An asymmetric density with no distinct margin or mass

effect: asymmetric density is a non-specific

mammographic finding that could be seen in clinically

normal breasts or in other various disease types.

Irregular ill-defined masses.

Diffuse increased density. Oval obscured masses in young women with

Heterogeneously dense breast. Calcifications in rare cases. Benign-looking axillary lymph node

enlargements. Skin thickening. Patients with dense breast parenchyma may

also have negative mammograms.

US FEATURES: Multiple clustered, often contiguous, tubular

hypoechoic lesions.

Hypoechoic mass.

Tubular hypoechoic areas connecting to a mass.

Irregular lobulated masses

Parenchymal distortions without definite mass.

Unusual Us finding of a focally decreased

parenchymal echogenicity and acoustic

shadowing.

Subcutaneous fat infiltration is minimal indicating

that the findings were not acute infection

MRI ASPECTS:o The Gd-DTPA-enhanced dynamic MRI shows

that IGM is associated with progressive

enhancement, which could be smooth or irregular,

with foci showing peripheral ring shaped contrast

enhancement pattern, with delayed washout.

o Such an enhancement pattern can mimic those of

inflammatory processes, a proliferative dysplasia,

and neoplasm.

o The real value of MRI might be in saving some

patients unnecessary surgery if an inactive lesion,

such as fibrosis or fat necrosis, is present.

o Such lesions, clinically and mammographically,

resemble carcinoma, but would not produce active

MRI enhancement pattern encountered in tumoral

or inflammatory processes.

TREATMENT:o The optimal treatment for GM has yet to be established. Surgical resection of the affected tissue, with or without corticosteroid therapy, has often been the current method of treatment.o However, with these treatments, a tendency for

local recurrences and delayed wound healing

exists.

CONCLUSION:

Clinical information and radiographic features of

GM may aid in the differentiation between IGM and

early onset breast cancer. However, a histological

confirmation is still required for a positive diagnosis

and the determination of an appropriate treatment

regimen.