is a very rare breast inflammatory disease of unknown
origin that can clinically mimic carcinoma of the breast.
The condition generally manifests as a distinct, firm to hard mass
that may involve any part of the breast. The subareolar regions may
be relatively spared. The relationship of granulomatous mastitis to
pregnancy or lactation has been strongly emphasized because this
disease entity typically affects younger women, usually within 6
years of pregnancy. Reactive lymphadenopathy may be present in up to
15% of cases.
Immunologic factors have been postulated as possible causes;
however, the absence of vasculitis or of a prominent lymphocytic
component in pathologic specimens favours against this hypothesis.
The diagnosis of idiopathic granulomatous mastitis is based on
exclusion, since it depends on the demonstration of a particular
histologic pattern combined with the exclusion of other
granulomatous reactions such as
and those other benign inflammatory disorders found in association
At pathologic analysis, idiopathic granulomatous mastitis manifests
as a non-caseating, nonvasculitic granulomatous inflammatory
reaction centered on lobules. Fat necrosis, abscess formation, and
fibrosis are commonly associated end-stage features that can disrupt
the normal lobular anatomy.
Mammographic features can be variable, ranging from normal findings
in patients with dense breasts to masses with benign or malignant
features and focal asymmetric density. The most common mammographic
appearance of the lesion is an asymmetrically increased density,
which is not characteristic for this entity 4.
Sonographic patterns of the disease are also varied and appear to
relate to the histologic features. Findings include a mass-like
appearance, tubular / nodular hypoechoic structures and focal
decreased parenchmal echogenicity with acoustic shadowing.
On MRI, the most frequent finding was focal or diffuse asymmetrical
signal intensity changes without significant mass effect. Nodular
lesions can also be seen 7.
T1 : regions tends to be hypo-intense
T2 : regions tend to be hyper-intense
dynamic contrast-enhanced MRI : can show mass-like enhancement,
ring-like enhancement, and / or nodular enhancement while
time-intensity curves can differ from patient to patient and from
lesion to lesion.
Treatment and prognosis
The prognosis is usually good, although local recurrence has been
reported. Primary treatment usually comprises of excisional biopsy.
Corticosteroid therapy has also proved effective.