Letter to the Editor Isolated lymph node amyloidosis

An 82-year-old man presented with a 5-year history of painless lymph node enlargement. He was completely asymptomatic, had no previous relevant medical history, and had worked as an office clerk. Physical examination showed cervical, inguinal, axillary, and submandibular lymph node enlargement, the largest measuring 5 cm in the cervical region. Neither organomegaly nor skin lesions were noted. Laboratory testing identified an Ig A kappa monoclonal protein. Urine protein electrophoresis was negative. Computed tomographic (CT) scanning of the thorax and abdomen demonstrated bilateral hilar and mediastinal calcified lymphadenopathy without parenchymal involvement. A transthoracic echocardiogram and a bone marrow biopsy showed no abnormalities. A submandibular lymph node biopsy showed effacement of the normal architecture by an eosinophilic, amorphous material, characteristic of amyloid, which was further identified as light chain type (AL) by immunohistochemistry. The patient remains well after 4 years of follow-up. Lymph node enlargement is not a prominent feature of the systemic amyloidoses. The AL form of amyloidosis is usually systemic, but rarely are organ-limited deposits in lymph nodes [1,2] and other sites of the body observed. The diagnosis of isolated lymph node amyloidosis requires demonstration of amyloid fibril deposition on lymph node biopsy without evidence of systemic involvement. Nodal calcification is frequently seen on CT scanning. In contrast to primary amyloidosis, isolated lymph node amyloidosis portends a good prognosis [1]. There is no specific treatment for this uncommon entity.