Postsurgical pemphigus vulgaris following thyroidectomy: a case report and review of the literature.

Rare diseases are often overlooked due to their low prevalence and may be classified as "idiopathic" once more common etiologies have been excluded. Nevertheless, rare conditions do occur, and clinicians must remain vigilant in considering them. Pemphigus vulgaris is a well-established autoimmune blistering disorder involving the skin and mucous membranes, with recognized triggering factors such as medications, infections, paraneoplastic processes, and trauma. Postsurgical pemphigus, however, represents an exceptionally rare variant, arising specifically at sites of surgical scarring. Unfortunately, once initiated, the disease frequently extends beyond the scar, involving widespread cutaneous and mucosal surfaces. Although postsurgical pemphigus is trauma related, it must be distinguished from posttraumatic pemphigus, which is associated with blunt physical injury rather than surgical intervention. We present the case of a 49-year-old woman who developed postsurgical pemphigus beginning at the scar of a prior thyroidectomy. She achieved partial clinical improvement with systemic therapy consisting of methylprednisolone and azathioprine.