Abnormal extraosseous activity in both lungs and stomach in pre-transplant 99mTc-MDP bone scan disappearing after renal transplant

Abstract

A chronic kidney disease male patient presenting with bone pains, fever, weakness, and clinically ascites was subjected to four technetium-99m-methylene diphosphonate (Tc99m-MDP) bone scans, two before renal transplant and two after renal transplants. Pretransplant bone scan revealed metabolic bone disease with focal insufficiency fractures. Marked extraosseous activity in both lungs and stomach was also visualized. On regular hemodialysis (HD) after 4 months, repeat pretransplant bone scan showed persistent uptake in lungs and stomach, representing altered calcium metabolism with microcalcifications. He underwent human leukocyte antigen (HLA) matched live donor renal transplantation, started on immune-suppression and steroids. Posttransplant bone scan at 20 days revealed no definite interval change, but bone scan performed approximately 17 months posttransplant showed resolving metabolic bone disease and the tracer uptake in the lungs and stomach was no more visualized. Patient clinically followed-up until the date (February 2013) is asymptomatic with serum creatinine of 1.5 mg/dl, no bone scan done.

Keywords: 99mTc-MDP; bone scan; chronic kidney disease; gastric uptake; hemodialysis; lung uptake.

Figure 1

Pre-transplant (a) whole body bone scan (b) static images in multiple projections shows abnormally increased periarticular radiotracer concentration. Both the kidneys appear small in size and are visualized with no definite excretion of tracer in the bladder. Abnormal diffusely increased radiotracer accumulation seen in both lungs and stomach. Focal increased radiotracer concentration involving the Medial and lateral cortices of distal shaft of both femora and medial cortex of mid shaft of bilateral tibiae representing insufficiency fractures

Figure 2

Second pre-transplant whole body bone scan dated (4 months later) on comparison with first bone scan revealed no definite new site of insufficiency fracture, insufficiency fractures involving the lateral cortices of distal shaft of both femora and medial cortex of mid shaft of bilateral tibiae were resolved, insufficiency fractures involving the medial cortex of distal shaft of both femora were significantly reduced in intensity representing healing insufficiency fracture. Abnormal tracer accumulation was persistent involving both lungs and stomach

Figure 3

Immediate (within 20 days) post-transplant whole body bone scan, no definite interval change noted compared to the second pre-transplant bone scan

Figure 4

Whole body bone scan performed approximately 17 months post-transplant, the tracer uptake involving the lungs and stomach had completely resolved