Case Report: Postmortem bone histomorphometric analysis in a 38-year-old Japanese man with immobilization osteoporosis because of orthostatic hypotension related to amyloid light chain amyloidosis

We performed a postmortem bone histomorphometric analysis of iliac bone on a 38-year-old man who had been bedridden for the nine months before his death because of orthostatic hypotension and severe malnutrition related to amyloidκ-light-chain amyloidosis. Cancellous bone volume was greatly decreased, with a trabecular bone volume to total bone volume ratio of 6.77% (normal value, 19.56% ± 5.62%). Trabecular thinning was also apparent, with a trabecular thickness of 78.9 μm (normal value, 131.3 ± 28.1 μm), although the trabecula was still preserved. Cortical bone width was normal, although areas of porosity area were clear throughout the cortical bone. Our findings indicate that immobilization-related osteoporosis may be closely associated with loss of cancellous bone.