Magnetic Resonance Imaging of Hidradenitis Suppurativa: A Focus on the Anoperineal Location.

Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease involving apocrine-bearing sites. It is characterized by recurrent painful nodules and abscesses that potentially rupture, resulting in sinus tract formation, fistulas, and scarring. HS tends to be found in the intertriginous areas (i.e., the axillary, inguinal, and perianal areas of the body). HS may be uncommon for radiologists because its diagnosis is usually based on clinical assessment. However, diagnosis based solely on clinical manifestations can underestimate the severity of HS. Ultrasonography and MRI play a critical adjunct role in determining the severity and extent of the disease and greatly aid its management. Given that MRI is an effective imaging tool, its role in the analysis of severe and anogenital HS lesions merits considerable attention. Unfortunately, anoperineal HS imposes diagnostic dilemmas. It has multiple symptoms and presentations and often mimics other diseases in the intertriginous areas. Therefore, a thorough understanding of HS is essential to avoid delayed diagnoses. This review highlights the typical MRI imaging features and staging of HS, emphasizing on the anoperineal location. The review also differentiates the disease from mimics to facilitate the prompt delivery of appropriate treatment and improve patients' quality of life.