[Erythema nodosum: a case report].

Background: Erythema nodosum is the most common clinical-pathological variant of panniculitis, presenting with erythematous nodular lesions. Infections are the most common cause. However, other causes cannot be ruled out: immunological, inflammatory, or metabolic. Therefore, the diagnosis must be multidisciplinary and direct treatment toward the underlying cause, as in most cases, it is usually the tip of the iceberg of a significant pathological process.

Case report: An 18-year-old female patient with a history of hepatoblastoma, nephrocalcinosis, and recurrent infections presented one month later with characteristic erythematous lesions on the left tibia, with subsequent edema and limited movement. Paraclinical studies were performed, and the diagnosis of septal panniculitis without vasculitis and perivascular inflammatory infiltrate was confirmed by biopsy.

Conclusion: Although erythema nodosum usually heals spontaneously, it can be the initial expression of infectious, immunological, or genetic diseases, so an early and multidisciplinary diagnostic approach is important to guide treatment and improve prognosis.