Globular amyloidosis of the colon.

Gastrointestinal involvement is frequent in systemic amyloidosis. However, amyloidosis can rarely be confined to the gastrointestinal tract or appear as a tumour mass. There have been few reports describing amyloid globular deposits in a variety of locations, as opposed to the usual linear ones. We herein report a rare case of globular amyloidosis involving the large bowel, which to the best of our knowledge is the second reported in the world literature. A 74-year-old man consulted on anaemia. Endoscopy showed ulcerative lesions in the left colon, which were biopsied and diagnosed as ischemic colitis. Under light microscopy, we found globular discrete deposits in the lamina propria which were Congo red-positive and resistant to permanganate digestion. Histopathological diagnosis was globular amyloidosis with AL deposits. The patient underwent further studies, including a haematologic evaluation that discarded systemic involvement. Globular amyloidosis seems to be a rare morphologic type of amyloidosis, but not a distinct entity. Its etiology, pathogenesis and relationship with patient prognosis and disease severity remain largely unknown. When amyloid deposits are confined to the gastrointestinal tract, systemic therapy can be avoided and patients should only be followed periodically. Immunohistochemical classification and clinical correlation are essential to rule out systemic amyloidosis. [ABSTRACT FROM AUTHOR]