An adverse effect of an injectable cosmetic procedure: a case of mistaken identities.

Minimally invasive cosmetic procedures are being performed at increasing rates. This is likely due to the combination of a growing aging population, an increased accessibility through non-physician providers, and a common association of "minimally invasive" with the concept of fewer side effects. Despite their overall successes, there are adverse effects associated with these procedures, which are most often related to injection location, amount, and technique. This case describes a patient who sought botulinum toxin injections to smooth the appearance of periorbital lines who presented 12 months later with chronic multiple palpable nodules in the injection sites. Histopathological evaluation demonstrated a foreign body reaction resembling the reaction against semi-permanent or permanent fillers such as poly-L-lactic acid or polymethylmethacralate. Knowledge of the biochemical properties and life cycles of dermal fillers guided the decision to surgically excise the nodules, with cosmetically satisfactory results.