Breast tuberculosis is usually secondary to a tubercular lesion elsewhere in the body, generally in the lungs. But when no other tubercular lesion is found except in the breasts the entity is labelled as PBTb.
Infections associated with reconstructive surgery and nipple piercing,1
dermal abrasions or through ductal openings at nipples in women of reproductive age is the usual mechanism7
although; often the exact mechanism remains unknown. Increased risk of PBTb has been reported in lactating females.4
PBTb accounts for only 0.06% to 1.78% cases of breast surgical cases in the west but reaches upto 4.5% in the east.1
Diagnosis of tuberculosis of the breast may be difficult because the clinical and radiographic appearances are non-specific. Furthermore, microbiological and histopathological results might not always be conclusive and affirmative. In our case, the discharge was positive for acid fast bacilli but the histopathology did not reveal any features of granulomatous disease. Cases have been reported where histopathology revealed features of granulomatous disease but pus was negative for acid fast bacilli.4
Primary breast tuberculosis is nothing but granulomatous lobular mastitis on histopathology and therefore its likely differentials are sarcoidosis, leprosy, syphilis, actinomycosis, typhus, and cat scratch disease.5
Morphologically three forms6
of breast tuberculosis are known and they are the nodular form which may be mistaken for a fibroadenoma or carcinoma,12
disseminated form that results into caseation and sinus formation, and a sclerosing form which manifests as dense, fibrotic breast tissue and is slow growing in absence of any suppuration. Our patient fits in the category of the disseminated form.
Clinically PBTb presents as a painless mass, oedema, or local abscess that is insidious in onset and is gradually progressive.4
Both the X-ray mammography as well as sono mammography findings are non-specific and variable depending upon the morphological subtype.3
To have a confirmed diagnosis of tuberculous mastitis acid fast bacilli have to be isolated from the tissue cultures. But many times these results of bacteriologic studies are negative,4
then a direct visualisation of a granulomatous lesion with caseous necrosis and bacilli on an acid fast stain of the histopathologic specimen10
aids in confirming the diagnosis. Hence we believe that microbiological as well as histopathological tests should be done to get a confirmative diagnosis.
Thus, although PBTb is a rare entity it must always be kept in mind in clinical, pathological and imaging wise benign looking lesions especially when such lesions do not respond to routine antibiotics. The correct diagnosis is often delayed and difficult because of the non-specific clinical, imaging, microbiological as well as histopathological findings. Hence a high index of suspicion acquires an important position. Therefore all methods must be employed untill a satisfactory diagnosis is reached.
Ultrasound can be effectively used for follow-up of these cases and to visualise response to ATT. Ultrasound can even aid in deciding whether to stop the treatment after completing the routine course or if lesions remain unhealed it can enable strengthening of the decision of further continuing the treatment until complete resolution has taken place. Evidently the disease is remarkably responsive to treatment with the modern antitubercular chemotherapeutic drugs and surgery has a background role to drain the pus if it is there.