Primary localized cutaneous amyloidosis with unusual clinical features in a patient with Sjögren's syndrome.

A 69-year-old woman presented with a 2-year history of an eczematous lesion covering the genital area. Histopathological examination showed deposits of amorphous, eosinophilic material and an infiltrate of plasma cells through the entire dermis into the subcutaneous fatty tissue. Congo red-stained deposits showed apple-green birefringence with polarizing microscopy. On immunohistochemistry, the deposited material was positively stained with anti-lambda light chain antibodies but not with anti-lambda light chain. A diagnosis of primary localized cutaneous amyloidosis (PLCA) was made, and the patient was also diagnosed as having Sjögren's syndrome (SjS) based on clinical and laboratory findings. The lesion of PLCA has spontaneously regressed over a period of 18 months. We report a unique case of PLCA and SjS that clinically demonstrated genital eczematous features and spontaneous involution, and we also describe a possible association between PLCA and SjS.