Primary Localized Cutaneous Nodular Amyloidosis on Scalp Successfully Treated with Excision

Abstract

Primary localized cutaneous nodular amyloidosis (PLCNA) is the rarest form of cutaneous amyloidosis, characterized by nodular deposits of light chain amyloids in the dermis and subcutaneous tissue, without apparent systemic involvement. One or several nodules are preferably located on the extremities, trunk, or face. The most useful stain for detecting amyloid fibrils is Congo red, which, when combined with polarized light, makes amyloid proteins appear apple-green under a microscope. Immunohistochemical staining can help identify the exact type of amyloid proteins. Although the exact etiology of PLCNA is unclear, removal of nodules by shaving or surgical excision has shown good results. To the best of our knowledge, only seven cases of PLCNA have yet been reported in the Korean literature. In three of these cases, the patients had lesions on the scalp. Herein, we present a case of a 34-year-old male with PLCNA on the scalp with all the results of immunohistochemical evaluation.

Keywords: Amyloidosis; Primary localized cutaneous nodular amyloidosis.

Fig. 1. Clinical features of the patient. (A) About 5 cm×3 cm sized, well-circumscribed, salmon-colored, waxy nodules on the occipital and right temporal scalp. (B) Occipital and temporal scalp without recurrence during a follow-up period of 18 months after surgical excision.

Fig. 2. (A) Deposition of massive amorphous, eosinophilic materials was observed throughout the entire dermis (H&E, ×40). (B) Amorphous, eosinophilic deposits can be seen next to normal dermal collagen (H&E, ×200). (C) The deposits were positively stained with Congo red (Congo red, ×200).

Fig. 3. Immunohistochemical staining with anti-kappa (A) and antilambda (B) antibody showed positive staining with both antibodies in the amyloid (black arrows) and the cytoplasm of the infiltrating plasma cells (white arrows) (×200).