Interchanging Autoimmunity - Lupus Mastitis Coexisting with Systemic Polyarteritis Nodosa.

Area of Science:

• Rheumatology and Dermatology
• Connective Tissue Diseases
• Autoimmune Disorders

Background:

• Lupus mastitis, an uncommon presentation of lupus erythematosus profundus (LEP), involves subcutaneous fat inflammation.
• LEP as the initial manifestation of lupus erythematosus (LE) is rare.
• Polyarteritis nodosa (PAN) and disseminated discoid LE (DLE) are distinct connective tissue diseases.

Purpose of the Study:

• To report a rare case of lupus mastitis as an initial manifestation of LE.
• To document the subsequent development of DLE and PAN in the same patient.
• To discuss the unexplained phenomenon of one connective tissue disease evolving into another.

Main Methods:

• Case report detailing clinical presentation, histopathological findings, and diagnostic criteria.
• Review of patient's medical history, including initial lupus mastitis and later development of DLE and PAN.
• Assessment based on American College of Rheumatology criteria for PAN and histopathological confirmation of DLE and lupus mastitis.

Main Results:

• The patient initially presented with histopathologically proven lupus mastitis.
• Years later, the patient developed disseminated discoid LE (DLE) and polyarteritis nodosa (PAN).
• The patient exhibited a negative antinuclear antibody profile despite meeting criteria for PAN and having DLE and lupus mastitis.

Conclusions:

• Lupus mastitis can be an initial, albeit rare, presentation of lupus erythematosus.
• The evolution of one connective tissue disease into others, such as DLE and PAN, is exceptionally rare and poorly understood.
• This case underscores the complex and sometimes unpredictable nature of autoimmune connective tissue diseases, even in the absence of typical serological markers like antinuclear antibodies.