The utility of ne-needle aspiration cytology in dierentiating granulomatous mastitis and tuberculous mastitis

Background: Tuberculous mastitis (TM) is a rare extrapulmonary presentation of tuberculosis accounting for less than 1% of all diseases of the breast in the industrialized world. Granulomatous Mastitis (GM) is an uncommon chronic inflammatory disease of the breast that almost always mimics cancer in young individuals, so it can be a diagnostic dilemma. Aims and objectives: The main aim of this study is to elucidate the utility of FNAC in differentiating granulomatous mastitis and tuberculous mastitis. Materials & Methods: A retrospective observational study was conducted at the department of pathology, Hindu Rao Hospital, Delhi. Cytology database was revealed for a period of 4 years (2016-2019). The clinical details wherever available and cytological morphology of individual cases were noted and analysed. Results: In our study out of 20 cases 11 cases (55%) were found to be granulomatous mastitis and the other 9 cases (45%) were found to be tuberculous mastitis. All cases were of female patients only, with equal side distribution. In the cytological smears of GM, three (27.3%) smears showed ductal epithelial cells, epithelioid cell granulomas were seen in 11 (100%) cases and singly scattered epithelioid cells were seen in nine (81.8%) cases. Caseous necrosis was observed only in one case (9.09%) but necrotic material intermixed with degenerated neutrophils and apoptotic bodies were seen in four cases (36.4%). Conclusion: FNAC can be an accurate method for differentiating tuberculous mastitis from granulomatous mastitis as per cytomorphological findings, along with confirmation by the demonstration of acid-fast bacilli and hence can help to decide the appropriate treatment protocols for such patients.


Introduction
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.

Materials and methods
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.   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].  [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].