Direct Myeloma Cell Invasion as One of the Major Causes of Renal Impairment In Myeloma A Pathological Analysis of Renal Findings In 41 Autopsied Cases

Renal insufficiency is one of the main complications in myeloma patients. Various causes were reported to be responsible for renal damage. Through analysis of an autopsied cases we would show the diversity of the renal diseases in myeloma.

We studied 41 autopsied myeloma cases from 1979 to 2008 at the National Center for Global Health and Medicine. The kidneys were evaluated by light microscopy using hematoxilin-eosin-stained sections, as well as Congo-red stain when amyloidosis was suspected.

There were 21 men and 20 women. Mean age at autopsy was 64.5 years old. The most common lesion was cast nephropathy (41.5%). The giant cell invasion was found in 35.3% of patients with cast nephropathy. Plasma cell tumor involvement was detected in 29.3% of all 41 autopsied cases. Fourteen per cent of cases had both cast nephropathy and plasma cell tumor involvement. In 75.6% of the patients, arteriosclerosis was found. In addition, 32% of the patients had the glomerular sclerosis which involved more than 20% of the glomerulus. Other findings include acute tubular necrosis (31.7%), AL-amyloidosis (19.5%), renal calcification (17.1%), bacterial and fungal infection (7.7%), micro thrombo-embolism (7.7%), mesangial proliferation (4.9%). At least one of above findings were detected in all cases and combined findings were detected in 65.9% cases.

We evaluated the renal manifestations in 41 autopsied cases in detail. In all cases, at least one pathological finding was detected. Cast nephropathy was the most common renal manifestation. However, direct myeloma cell invasion was found in 29.3% and combined pathologic findings were common.

No relevant conflicts of interest to declare.