Clinical and radiological evidence of the recurrence of reversible pegvisomant-related lipohypertrophy at the new site of injection in two women with acromegaly: a case series

INTRODUCTION: Pegvisomant-related lipohypertrophy may revert when changing the site of injection, but the lipohypertrophy may recur at the new site of injection. The strength of evidence, however, is weak and comes from information obtained from physical examination only. CASE PRESENTATION: We studied two Caucasian women with acromegaly, aged 51 and 71 years, with pegvisomant-related lipohypertrophy. Our two patients were evaluated at baseline, when the site of pegvisomant injection was the periumbilical abdominal region, and then four months after switching the injection site from the abdomen to both thighs. Both physical examination and radiological studies (magnetic resonance imaging and dual energy X-ray absorptiometry) demonstrated that the abdominal lipohypertrophy progressively reverted in both patients after switching the site of injection to the thighs. However, lipohypertrophy reappeared at the new site of injection. The radiological outcome confirmed the reversibility of pegvisomant-related lipohypertrophy and strengthened the body of evidence on this issue. CONCLUSION: In clinical practice, physical examination of the injection site or sites leads to an early detection of lipohypertrophy during pegvisomant treatment. Radiological procedures may be of help to confirm subcutaneous fat changes and for a precise monitoring of fat redistribution. Patients should get appropriate information about lipohypertrophy before starting pegvisomant treatment since the rotation of the site of injection may prevent lipohypertrophy.