Systemic immunoglobulin light-chain amyloidosis (AL) in Mexico: a single institution, 30-year experience.

MATERIAL AND METHODS: In a 30-year period in a single institution, 23 cases of systemic immunoglobulin light chain amyloidosis (AL) were identified, within a group of 1,388 individuals with some form of a hematological malignancy.

RESULTS: AL is 14 times less frequent in Mexico than in Caucasians and it represents 15% of all monoclonal gammopathies. Median age was 57 years (range 39-98); there were 11 males and 12 females. The histologic diagnosis was done in the periumbilical fat in 39%, the bone marrow in 30%, the kidney in 13%, the gastrointestinal tract in 13% and in a lymph node in one case. The nephrotic syndrome was present in 61% of cases, heart failure in 35%, sensorimotor peripheral neuropathy in 26% and weight loss in 6%. Anemia was present in 14% of cases at diagnosis; median hemoglobin was 11 g/dL. An abnormal monoclonal spike in the peripheral blood was present in 70% of cases; it had a median of 1.2 g/dL (range 0.2-3.6); there were 7 cases of light-chain only disease and five in whom an abnormal paraproteinemia was not found. Six cases were associated with overt multiple myeloma. Seventeen individuals (74%) were followed for more than 3 months (range 90 to 5190 days, median 210); their overall survival (OS) was 71% at 173 months, whereas the median OS has not been reached, being above 173 months. Eight patients were treated with melphalan/predisone and five were given high dose chemotherapy and an autologous stem cell transplantation; the others were given other treatments.

CONCLUSIONS: AL is less frequent in Mexican mestizos and probably underrecognized; the clinical features of the disease are not significantly different from those informed from other populations.