Primary systemic amyloidosis initially presenting with digestive symptoms: a case report and review of the literature

Primary systemic amyloidosis (PSA) is one of systemic amyloidosis, characterized by clonal plasma cell disorder. The disease is rare and with high fatality. Signs and symptoms of PSA are various and complex, which depend on the organs involved. Here we report a case in which the patient initially suffered from gastrointestinal symptoms. Gradually periorbital purpura, skin fragility, and subsequent petechiae, ecchymoses and sclerosis of the distal limbs, appeared. Biopsy of his palmar skin showed scleroderma-like changes. However, histopathology of the petechiae lesion on forehead with Crystal Violet Staining prompted deposition of amyloid; gastric mucosal biopsy with Congo Red staining was also positive, which made clear the diagnosis of PSA. Bone marrow biopsy and serum immunofixation electrophoresis (IFE) revealed plasmacytosis and M proteinemia. Other examinations were performed to assess the function of organs. PSA was challenging due to the initial atypical clinical presentation and absence of biopsy with special staining. The case demonstrates that PSA should be considered in patients with multisystemic symptoms and biopsy with Congo Red staining should be performed to exclusively diagnose amyloidosis.