In 1829, Sir Astley Cooper defined breast tuberculosis as the ‘scrofulous swelling of the bosom’.6
The lump is the most common presentation in breast tuberculosis.7
These breast lumps are mostly misdiagnosed as fibroadenoma, fibroadenosis, malignancy or breast abscess. The three main features of breast TB are nodular, disseminated and sclerosing, and these features result in multiple discharging sinuses, lumps, ulcers and recurring abscesses of the breast are observed. Tubercular lumps are mostly irregular, ill-defined and mostly more painful than that seen in carcinoma. Pain is usually dull and constant in breast TB. In Puneet’s series,7
12 patients were clinically misdiagnosed as fibroadenoma, 17 as fibroadenosis and 8 as carcinoma.
Breast tuberculosis commonly affects young multiparous, lactating women. Although cases have been reported from age 6 months to 73 years, most were between 20 to 40 years old.8,9
All of these cases were multiparous, and their mean age was 33 years. According to Wilson,10
the right and left sides of the breast were involved equally often. In contrast, Pal11
reported that there is a slight tendency for the right breast to be more frequently affected as it was in our patient series. Sharma12
found that the duration of symptoms ranged from 6 months to 2 years, and in the case series of Khanna,13
the mean duration of symptoms was 8.5 months.
Breast TB may be considered primary when no other demonstrable focus exists, and may be considered secondary when a preexisting lesion is located elsewhere. M. tuberculosis
can spread to the breast by the lymphatic and hematogenous routes or directly, and it can persist for long periods within the body. It is generally thought that the breast gets involved in tuberculosis by retrograde lymphatic extension from the mediastinal, axilla and cervical region,13
but in the cases reported here, there was no associated lympadenopathy as confirmed by physical exam and ultrasonography and no other foci of tuberculosis infection, and all chest x-rays were normal. Direct infection of the breast may occur through skin abrasions or through the milk duct openings. All three patients were in their reproductive ages with multiple children, all of whom were breastfed for at least 6 months. Lactation is known to increase the susceptibility of the breast to tuberculosis since during lactation, the increased vascularity of the breast may facilitate infection and dissemination of the bacilli. Shinde5
found that 7% of their patients were lactating at the time of presentation, while Banerjee3
reported that 33% of their patients were lactating. Two of these patients had recent lactation history.
Although it is very specific and acts as the gold standard for the diagnosis, M. tuberculosis
stain, culture or PCR is not very sensitive, and this may cause some additional delays for diagnosis and under-diagnosis.14
Bacteriological examination of discharge from the sinus was negative for M. tuberculosis
on staining as well as culture in most cases.15
However, all of these cases had breast TB, as they responded to antituberculosis treatment. The bacteriological results were negative for staining, culture and polymerase chain reaction (PCR) tuberculosis tests. Environmental conditions can alter the physiology and virulence of M. Tuberculosis
, since it requires oxygen for its growth and survival. As the mammary gland tissue may convey some resistance to the survival and multiplication of the tuberculosis bacillus, we expected that the number of M. tuberculosis
bacilli in the tissue would be small, making it difficult to prove their existence. On the other hand, an AFB-positive smear can be seen from other mycobacteria species, so it is not a definitive mycobacterial diagnosis for TB. Most of the time, pathological examinations are more valuable than bacteriological examinations and are preferred for the accurate diagnosis of breast TB. Khanna13
found that in 52 patients with breast TB, fine needle aspiration cytology (FNAC) was 100% reliable in diagnosing breast TB. A newly developed T-cell–based, whole-blood enzyme-linked immunosorbent interferon release assay detects interferon. Interferon is secreted by T cells in response to antigens encoded in the region of difference 1 of M. tuberculosis
, a genomic segment absent from Calmette–Guerin bacilli and most environmental mycobacteria. Thus, the test confers a higher specificity than the tuberculin skin test.16
Moreover, results are available in 24 hours. Unfortunately, we could not perform these tests in our hospital.
Histopathological confirmation of breast TB requires cytological evidence of caseous necrosis epitheloid granulomas and Langhans giant cells with lymphohistocytic aggregates. The differential diagnosis of breast TB includes other granulomatous inflammatory diseases, such as idiopathic granulomatous mastitis (GM), sarcoidosis, Wegener’s granulomatosis and giant cell arteritis, as well as other infections like actinomycosis and fat necrosis. In idiopathic GM, the granulomatous inflammatory reaction, consisting of epitheloid and giant cells, is confined to the breast lobules in which there is also leukocyte infiltration and abscesses but no caseation.17
In breast TB, the distribution of granulomas is diffuse and is not limited to the lobules, and they are accompanied by caseation necrosis. This necrosis results in the characteristic fistulization of skin lesions. In plasma cell mastitis, there is inflammation in the breast tissue in response to the irritating quality of fatty material accumulated in dilated ducts. The granulomatous reaction in traumatic fat necrosis is confined to the broken down fat globules. Fat necrosis can also be eliminated as a diagnosis by the absence of fat globules. With appropriate serological investigation, arteritis, the absence of sulfur granules in the discharge of the sinus of the suppurating lesions and actinomycosis can all be eliminated from the differential diagnosis.18
Radiological imaging modalities like mammography or ultrasonography are unreliable in distinguishing tuberculosis mastitis from carcinoma because of its nonspecific features.19
Similarly computed tomography and magnetic resonance imaging are not diagnostic without histological confirmation.
Immunosuppressive conditions, like organ transplantations and HIV infections, advanced age, and chronic diseases, increase the chance that tuberculosis presents atypically with extrapulmonary manifestations that can result in delays in diagnosis and treatment. A high degree of clinical suspicion and familiarity with physical examination findings are necessary to enable an early diagnosis. This requirement for familiarity motivated us to present our experience with breast TB to increase the awareness of other doctors of this condition, and to enable the prevention of delays in the diagnosis of breast TB and of unnecessary interventions and surgical procedures.