A skin biopsy was performed to the cat with erythema, scale, alopecia distributing from back to hip and erosion around eyes. Histopathological examination on the skin biopsy specimen suggested systemic lupus erythematosus as one of differential diagnoses. Antinuclear antibody and severe proteinuria with urinary casts were detected. By renal biopsy, membranous nephropathy was histopathologically diagnosed.
