Interchanging Autoimmunity - Lupus Mastitis Coexisting with Systemic Polyarteritis Nodosa.

Lupus mastitis is an uncommon presentation of lupus erythematosus profundus (LE profundus), characterized by inflammation of the subcutaneous fat. LE profundus occurring as initial manifestation of LE is rare. We report a case where the patient presented with lupus mastitis and years later, she developed disseminated discoid LE (DLE) and polyarteritis nodosa (PAN). PAN and DLE are connective tissue diseases with different etiologies, clinical, immunological, and histopathological features. One connective tissue disease evolving into another is rare, and the reasons remain unexplained. This woman had histopathologically proven DLE and lupus mastitis with a negative antinuclear antibody profile. She satisfied the American College of Rheumatology criteria for PAN.

What was known?

Lupus mastitis occurs as a manifestation of systemic lupus erythematosus (SLE) or discoid lupus erythematosus. SLE can evolve into polyarteritis nodosa.

Introduction

Lupus mastitis presents as single or multiple subcutaneous or deep breast masses, clinically mimicking malignancy [Figure 1]. Lupus mastitis is rare, with <25 cases reported in literature. Lupus mastitis presenting as the initial manifestation of lupus erythematosus (LE) is very rare. Later, she developed discoid LE (DLE) lesions on breast and other sites without any systemic symptoms of LE [Figure 2]. Moreover, subsequently, patient developed polyarteritis nodosa (PAN). Evolution of one connective tissue disease to other remains a perplexing event, though there are reports. Literature search shows only a single case of DLE progressing to systemic PAN even though many cases of systemic LE evolving to systemic PAN has been reported.[1]

Figure 1

Right breast shows atrophy, discoid lupus erythematosus lesions on surface

Figure 2

Discoid lupus erythematosus lesion in ear

Case Report

A 35-year-old female presented with hyperpigmented papules on right breast, face and limbs, and weakness of right little finger of 2 weeks duration. She gave a history of asymptomatic swelling of breast of 5 years duration. She was diagnosed to have malignant hypertension 2 months back. There was no history of tuberculosis, joint pain, photosensitivity, or Raynauds phenomenon.

Cutaneous examination revealed multiple hyperpigmented discrete and confluent atrophic plaques with adherent scales over the right breast. Breast tissue also showed induration with multiple discrete nodules of size 1 cm × 2 cm. Axillary nodes were normal. Multiple discrete hyperpigmented scaly papules and plaques were present on the upper arms, face and ear concha (Schuster sign) [Figures 1 and 2].

Right ulnar nerve palsy was present; her blood pressure was 220/110 mm Hg.

We had the differential diagnosis of papulonecrotic tuberculid and disseminated DLE (DDLE); for the breast nodules, we considered tuberculous mastitis and lupus mastitis.

Blood routine was normal except raised erythrocyte sedimentation rate 110 mm. Urine routine showed albuminuria, but 24 h urine protein was normal. Renal function test, antinuclear antibody (ANA), ANA profile, and C3, C4 levels were normal. Mantoux test, perinuclear anti-neutrophil cytoplasmic antibody, and viral markers were negative. Ultrasonography (USG) abdomen showed features suggestive of medical renal disease. Doppler showed decrease flow in both intrarenal arteries.

Magnetic resonance imaging aortogram revealed luminal irregularity and beaded appearance of left renal artery near the hilum. Nerve conduction study was suggestive of right ulnar neuropathy. Skin biopsy was suggestive of DLE [Figure 3].

Figure 3

Skin biopsy from breast lesion shows atrophy of epidermis, follicular plugging, and basal cell degeneration

Deep biopsy from breast showed features of DLE with mixed panniculitis and lymphocytic vasculitis with mucin deposition in dermis, suggestive of lupus mastitis [Figures 4 and 5].

Figure 4

Deeper biopsy from breast tissue shows lymphocytic vasculitis and lymphoid aggregates

Figure 5

Alcian blue stain shows mucin deposition in dermis

USG breast showed ill-defined hypoechoic mass with atrophy of fat and large calcifications in fat and breast tissue [Figure 6].

Figure 6

Ultrasound picture of breast shows atrophy of breast tissue, large masses of calcification

Hence, the final diagnosis was lupus mastitis evolving to DDLE and systemic PAN.

She was started on systemic steroids and hydroxychloroquine, and she responded well.

Discussion

Lupus mastitis affects women with a mean age at diagnosis of 40 years and can occur in males also. The condition leads to fat necrosis, calcification, fibrosis, scarring, and breast atrophy. Most commonly, lupus mastitis is seen in patients with a previous diagnosis of systemic or discoid lupus.[2] However, in our patient, lupus mastitis was the initial presentation.

In the absence of skin lesions and background of LE, it poses a diagnostic challenge and the differential diagnosis involves carcinoma, tuberculosis, idiopathic granulomatous mastitis, lymphoma, and involvement of breast in medium vessel vasculitis.

Traumatic procedures such as biopsy may worsen the condition,[3] and it is advisable to avoid biopsy if the diagnosis can be established with the clinical and radiological features. Fine-needle aspiration cytology shows degenerated fat cells with scattered foci of calcification and lymphocytic predominance.

Histological findings in lupus panniculitis are hyaline fat necrosis, lymphocytic infiltration surrounding the necrosis, periseptal or lobular panniculitis, and microcalcifications.[4] Other findings include changes of DLE in the overlying skin, lymphocytic vasculitis, mucin deposition, and hyalinization of the subepidermal papillary zones. All these features were present in our patient.

Typical mammographical appearance include segmental heterogeneous calcifications, some curvilinear and coarse due to fat necrosis. Diffuse increased density of fibro glandular tissues and decreased breast size are seen.[4] Ultrasound shows an ill-defined, isoechoic, or hyperechoic mass, but our patient had hypoechoic lesion, large calcifications, and lipoatrophy.

This patient had lupus mastitis initially and years later developed DDLE lesions. She also satisfied the criteria for systemic PAN.

In 1990, the American College of Rheumatology established criteria for PAN.[5] At least 3 of the 10 criteria should be present:

Weight loss >4 kg

Livedo reticularis

Testicular pain

Myalgia

Mononeuropathy or polyneuropathy

Diastolic blood pressure >90 mm/Hg

Elevated blood urea nitrogen or creatinine level

Presence of hepatitis B surface antigen

Arteriogram demonstrating aneurysms

Biopsy of small- or medium-sized artery containing neutrophils.

Our patient satisfied this criteria, and literature search showed few reports of systemic lupus erythematosus (SLE) progressing to PAN, but only a single report of DLE going for PAN.[6] In this case, we faced two questions, is the breast swelling lupus mastitis or PAN of breast tissue and whether the patient has a single connective tissue disease or both LE and PAN. However, the histopathology and radiology provided evidence for the coexistence of both.

We report this case as lupus mastitis is a rare entity, and its presence as the initial manifestation of LE is still rare. It remained quiescent for many years and then developed DDLE and systemic PAN.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

What is new?

Lupus mastitis presented as initial manifestation of LE, so it remained undiagnosed for many years. Even though there are reports of SLE evolving to PAN, a case of DLE going to PAN is rare.