Iatrogenic allogenosis

Iatrogenic allogenosis is also known as a reaction to foreign modelling agents. It is a reaction from solid or liquid substances injected for aesthetic reasons, especially in the calves, face, buttocks, and breasts. Foreign modelling agents or  "biopolymers" that may be used include liquid silicone, mineral oil, paraffin, liquid petroleum, animal fat, acrylic, and many more.

Specimen analysis indicates chronic granulomatous inflammation with a foreign body reaction, with foamy histiocytes or multinucleated giant cells with phagocytized foreign material. Fibrotic areas may appear interspersed with the granulomatous response.

The adverse reactions to soft tissue filling substances are local and general.  The local reactions are erythema, swelling, pain, pigmentations, fibrosis, infection, necrosis, ulceration, gravity displacement, and others.  General reactions are fever, chills, malaise, Autoimmune/Inflammatory Syndrome Induced by Adjuvants ('ASIA'), and even death.

Greyscale ultrasound image show hyperechoic deposits in the dermis and subcutaneous tissue with a "snow storm" pattern.

CT may be used to determine the dimensions and densities of substances in soft tissues and is an essential component of preoperative planning for surgery.

Signal characteristics can vary according to the substance used :

  • T1: rounded hypo to isointense material
  • T2: rounded hyperintense material
  • T1 C+: heterogeneous enhancement by an inflammatory process

Treatments include incision and drainage of abscesses, surgical removal or debridement of necrotic tissue, surgical or ultrasound liposuction, and anti-inflammatory drugs or systemic steroids.


Share article

Article information

rID: 68567
Section: Syndromes
Synonyms or Alternate Spellings:
  • foreign modelling agent reaction
  • biopolymers

Support Radiopaedia and see fewer ads

Cases and figures

  • Case 1
    Drag here to reorder.
  • Updating… Please wait.

     Unable to process the form. Check for errors and try again.

     Thank you for updating your details.