SLE is an autoimmune disease in which pathogenic autoantibodies are the primary cause of tissue damage. People of all ages, all ethnic groups, and both sexes are affected, but 90% of the cases occur in women of childbearing age.[4
] Kaposi first proposed the term ‘lupus panniculitis’ in 1883.[5
] Irgang introduced the term ‘lupus profundus’ for the inflammation of the subcutaneous fat that occurs in 2–3% of SLE patients.[1
] Involvement of the breasts, called lupus mastitis, is rare. According to some sources, not more than 10 cases (and according to Niger et al
., not more than 16 cases) have been reported to date.[2
] The disease, as expected, is more common in women in the age-group of 20–50 years, though cases have also been reported in men.[7
] Patients may present with recurrent breast swellings, with or without pain. Clinically, multiple subcutaneous nodular swellings are palpable, with or without involvement of the overlying skin.[9
] The pathophysiology of lupus mastitis is unknown. One belief is that local trauma, including that due to biopsy, may precipitate lupus mastitis and that it may herald SLE.[10
] However, in our opinion (and as also reported by others) lupus mastitis is an extension of the inflammatory process that involves the overlying skin. If the breasts are involved in the absence of skin involvement, the process may be the result of vasculitis.[2
] Traumatic procedures like biopsy may worsen[3
] the condition and it is advisable to avoid biopsy if the diagnosis can be established with the clinical and radiological features (especially the unusual mammographic calcification) as was possible in our patient. FNA will be helpful if there is a doubt about the diagnosis or when the swelling is localized. Degenerated fat cells with scattered foci of calcification and lymphocytic predominance are the classic findings seen on microscopic examination. Cytology has been reported to be capable of differentiating between granulomatous mastitis and other benign lesions or malignancies.[11
Histological findings in lupus panniculitis include mainly: 1) hyaline fat necrosis, 2) lymphocytic infiltration surrounding the necrosis, 3) periseptal or lobular panniculitis, and 4) microcalcifications. Other findings include changes of discoid lupus erythematosus in the overlying skin, lymphocytic vasculitis, mucin deposition, and hyalinization of the subepidermal papillary zones. The presence of these findings differentiates lupus panniculitis from other forms of panniculitis.[9
] The classic finding in lupus mastitis is necrosis surrounding blood vessels, associated with heavy perivascular and periadenexal lymphocytic infiltrates and hyaline sclerosis of the dermal collagen. The presence of sclerosis and calcification are responsible for the hard, carcinoma-like feel of lupus mastitis and the unusual pattern of calcifications on mammography.
The differential diagnosis of lupus mastitis includes breast carcinoma, non-Hodgkin's lymphoma, uncommon manifestations of other connective tissue diseases (e.g., rheumatoid arthritis, polyarteritis nodosa, relapsing polychondritis, and Wegener's vasculitis), and idiopathic granulomatous mastitis. The clinical features and histology are helpful in differentiating between these conditions.[11
Our case was straightforward, as she was a known case of SLE and the diffuse calcifications of a benign disease, suggestive of fat necrosis, were evident; however, the clinical presentation of constitutional symptoms, presence of submandibular swelling, axillary lymphadenopathy, hepatomegaly, and pericardial effusion made it necessary to rule out diseases like lymphoma, malignancy, and tuberculosis, and therefore we performed biopsy and mammography. Later, review of literature helped us to identify and understand not only the unique mammographic features but also the biopsy, FNA, CT scan, and USG findings.
Thus, in a clinical setting such as ours, the radiological and clinical features alone should suffice to make a diagnosis of lupus mastitis; FNA may help resolve doubts in unusual presentations and thus the complications of atrophic scarring and ulceration that are reported with biopsy can be avoided. With such an approach, it should be possible to avoid unnecessary surgeries and mastectomies and their consequences.[12