Anogenital Papular Mucinosis in Chronic Anal Fissures: A Review of a Reactive Mucinous Pattern

Background Anogenital papular mucinosis (APM) is a rare localized cutaneous mucinosis characterized by dermal mucin deposition presenting as flesh‐colored papules in the anogenital region. Its rarity and clinical resemblance to common infectious and inflammatory dermatoses contribute to frequent misdiagnosis. Objectives To summarize the clinical presentation, histopathology, differential diagnosis, and proposed pathogenesis of APM, with emphasis on cases occurring in patients with chronic anal fissures. Methods Narrative review of published reports and clinicopathologic literature addressing anogenital presentations of papular mucinosis, histologic diagnostic features, and proposed mechanisms including fibroblast dysregulation and trauma‐related cytokine signaling. Results Across reported cases, APM typically presents as asymptomatic or mildly pruritic dome‐shaped papules. Biopsy demonstrates abundant superficial‐to‐mid‐dermal mucin highlighted by Alcian blue staining, with sparse fibroblasts and minimal inflammation—features that distinguish APM from condyloma, molluscum contagiosum, lichen planus, and lichen nitidus. Emerging evidence supports a trauma‐associated framework in which chronic fissuring and microinjury may stimulate fibroblasts and extracellular matrix remodeling, leading to localized mucin accumulation. Conclusions APM may be best interpreted as a benign, localized mucinous reaction pattern within the spectrum of lichen myxedematosus rather than a distinct clinicopathologic entity. Recognition prevents unnecessary treatment and stigma and, in perianal cases, should prompt attention to fissure management and reduction of mechanical trauma.