Granulomatous Mastitis (GM) is an extremely rare chronic inflammatory disease of the breast that almost always mimics cancer in young individuals [1]. Aetiologically GM is divided into specific and non-specific types. The term “specific GM” is used when the aetiological factor can be identified [1]. These may be categorised as infectious causes like Mycobacterium tuberculosis.

GM should be distinguished from tubercular mastitis because they have overlapping clinical, radiological and cytological features and also because their treatment differs considerably. The pathogenesis of granulomatous mastitis is unclear, as its relation to the duct ectasia or periductal mastitis group of conditions, in which a granulomatous inflammatory component may be present [2].

Tuberculosis is the most widespread and persistent human infections in the world which can involve any organ. But tuberculosis of the breast is a rare form of tuberculosis [3,4]. Among all breast lesions, the incidence of tubercular mastitis is less than 0.1% in Western countries whereas in tuberculosis endemic regions, such as India and Africa the incidence reaches up to 3% [5,6]. It commonly affects young women in the reproductive age group particularly during the lactational period. It is also reported in prepubescent males and elderly women [7]. The breast tissue is remarkably resistant to tuberculosis [8].

The disease most commonly presents as a lump in the central or upper-outer quadrant of the breast, however multiple lumps appear less frequently. Because of its nonspecific features mammography has a limited role in the diagnosis. It is a diagnostic challenge as it closely mimics carcinoma of the breast and pyogenic inflammatory disease. When other routine laboratory investigations do not help to conclude tubercular mastitis, Fine needle aspiration cytology (FNAC) is a very essential diagnostic tool. We have reviewed 20 cases of tuberculosis of the breast here, which were rare manifestations of a common disease in a country like India.

The present study is a retrospective observational study was conducted at the department of pathology of a tertiary care hospital, Delhi.

The median duration of symptoms was 3 months (range 1 to 24 months) in GM patients and 7 months (range 2 to 60 months) in TM patients. (Table 1). A history of pulmonary TB was found in six (30%) patients and 8 patients were lactating mothers.

Table.1 Clinical findings in GM & TM

*- student’s t-test, $- Mann-whitney test, #- z-test

On palpation, the majority had a firm to hard, ill-defined lump with tenderness present in five patients of GM and two TM patients. Four patients had multiple discharging sinuses in the breast. Lymphadenopathy was more commonly present in TM patients with a p-value of 0.068. A definitive diagnosis of breast tuberculosis was established on FNAC in nine cases (45%) based on morphologic features and presence of AFB, while the diagnosis of the remaining eleven cases (55%) was suggested on FNAC smears as granulomatous mastitis and advised for PCR to rule out tuberculosis.

Fig-1: Incidence of granulomatous mastitis and Tuberculous mastitis.

In the cytological smears of eleven GM patients, three (27.3%) smears showed ductal epithelial cells, many of them exhibiting reactive atypia. Epithelioid cell granulomas were seen in 11 (100%) cases and singly scattered epithelioid cells were seen in nine (81.8%) cases.

Tuberculosis in the breast is an extremely rare disease, because mostly organs or tissues like the spleen, breast and skeletal muscle are more resistant to the infection, making the survival and multiplication of the tubercle bacilli difficult. In India, the incidence of tuberculous mastitis has been reported to be between 1 - 4.5% [10]. Sir Astley Cooper reported the first case of breast tuberculosis and he described it as “scrofulous swelling of the bosom [11].

Tuberculous mastitis is more commonly seen in females of the reproductive age group particularly during the lactational period [12,13,14]. Because during lactation the mammary gland is more vascular and predisposed to trauma [15]. In our study age of patients ranges from 19 yrs to 50 yrs (mean age 28.05 +/- 5.05) and 8 patients were in lactation (40%). Both breasts are involved with equal frequency. However bilateral disease is very rare which occurs in 3% of patients [14]. Our study shows right-sided involvement in 10 patients (50%), while left breast involvement was found in the other 10 patients (50%). There was no case of bilateral involvement in this series. The duration of symptoms varies from a few months to several years, but in most cases it is less than a year.

Granulomatous mastitis (GM) is an uncommon inflammatory lesion of the breast which is due to various etiologies like tuberculosis, fungal infections, connective tissue disorders, fat necrosis and sarcoidosis. If no attributable cause is detected then it is termed idiopathic which was first described by Kessler and Wolloch in 1972 [16]. Tuberculous involvement of the breast can occur in two forms. The primary form is through infection of the breast by abrasions or through the openings of ducts in the nipple. The secondary form is through retrograde lymphatic flow in the axillary lymph nodes or may be due to the direct spread of the infection from intra-thoracic foci.

The most common presenting symptom is the breast lump. Multiple lumps are less frequent. The classical presentation of matted nodes, multiple sinuses, ulcers and the breast mass is less common, which makes clinical diagnosis difficult. Other uncommon presentation can be purulent discharge from the nipple, a typical tuberculous ulcer or a fluctuant swelling which if accidentally incised produce discharging ulcer [17]. In our study five patients (25%) had associated signs of inflammation in the form of redness and raised temperature.

[21]. The gold standard diagnosis of Tuberculous mastitis is a bacteriological culture or demonstration of acid-fast bacilli by Ziehl Neelsen (ZN) stain.

The optimal treatment of GM is controversial. In most cases, steroid therapy has a good response. Wide surgical excision is advised in complicated cases, while TM requires antitubercular therapy for six months like pulmonary tuberculosis [22]. A flareup of infection can occur in cases of TM as GM is treated with steroid or methotrexate which can be harmful to the patient.

Hence, we recommend in cases of GM, tubercular aetiology must be ruled out with a repeat FNAC. All patients should receive adequate anti-tubercular treatment (ATT). After completion of ATT the residual lumps are be excised via segmental or sector mastectomy. Radical mastectomy is avoided until and unless if there is a co-existing malignancy.

The limitations of the present study are that all the cases of GM which are diagnosed on cytology were not followed up for histopathological diagnosis which is the gold standard test for GM. All the cases of TM which were diagnosed based on ZN staining are the less sensitive test. PCR test which is a sensitive and specific test for TM could not be performed due to financial constraints.

Although granulomas may be seen in both granulomatous mastitis and tuberculous mastitis, there are cytomorphological differences between the two entities. We found that well defined epithelioid cell granulomas are more common in granulomatous mastitis. Moreover, foreign body giant cells were seen in a fair number of granulomatous mastitis cases. Whereas, Langhans giant cells were more common in tuberculous mastitis.

Keeping in mind the difference in treatment of these two entities, the cytomorphological differences as suggested by this study may help decide the appropriate treatment protocols of such patients.