Diffuse pigmentation of back and arms: macular amyloidosis or other?

The study was undertaken to answer the question that how many patients with pigmentation of back and arms actually have amyloid deposits in pathology. 44 patients presenting with diffuse pigmentation of back and arms (DPOBA) were selected. Skin biopsies were performed in all cases from the affected sites. On all formalin fixed and paraffin embedded specimens, the following histochemical stains were performed: Haematoxylin and eosin (H&E), Congo red and immunohistochemical staining using anti-cytokeratin monoclonal antibody. In 9 of 44 cases (20%), amyloid deposits were found. In the remaining 35 cases (80%), H&E, Congo red and immunohistochemical staining failed to show any amyloid deposition. We were unable to find amyloid deposition in most of the patients presented with DPOBA. It seems that the signs may be attributable other disorders with similar clinical but different pathophysiologic aspects.