P043 Painful evanescent palmoplantar nodules: an under-recognized recurrent necrobiotic disorder with systemic associations

Abstract

Differentials of painful transient palmoplantar nodules include erythema multiforme, vasculitis and eccrine hidradenitis. Palmoplantar granuloma annulare (GA) and palisaded neutrophilic granulomatous dermatitis (PNGD) represent under-recognized necrobiotic causes. We aimed to characterize the clinicopathological spectrum of painful evanescent palmoplantar nodules and identify histological discriminators between palmoplantar GA and PNGD, with their recurrence and systemic associations. We analysed a retrospective series of consecutive biopsied cases (2019–2025) from a North Indian tertiary centre presenting with painful or tender palmoplantar nodules. Clinical, follow-up, systemic investigations and histopathology data were analysed. Seventeen patients (6 male, 11 female; mean age 49.4 years) presented with mainly palmar nodules (15 of 17), with or without plantar (7 of 17) or dorsal (6 of 17) extension. The lesions self-resolved (mean 5.5 weeks) but recurred in most. The proportions of those with recurrent disease were 12 of 17 (70%) overall and 12 of 13 (92%) among those with follow-up. In those with recurrent disease, a mean of 3.3 episodes per year were seen, with a mean observed duration of 1.9 years from the first episode. Systemic disease occurred in 10 of 17 (59%), including hypothyroidism (3), diabetes (3), connective tissue disease (3) and polyarteritis nodosa (1). Cases showing annular palisading of granulomas, interstitial granulomas, mucin (7 of 10 alcian blue positive) and predominantly lymphohistiocytic infiltrate were classified as GA (n = 10), while those with fibrinoid vasculopathy, leucocytoclasia, neutrophils, oedema and predominantly perivascular infiltrates were classified as PNGD (n = 7). Leprosy pattern (superficial and deep perivascular and periappendageal infiltrates) was seen in 4 of 17, and elastophagocytosis in 2 of 17. Cases of PNGD had significantly higher recurrence (100% vs. 60%, P = 0.04; probably because they had more follow-up) and higher association with systemic disease (86% vs. 40%), although this difference was not statistically significant (P = 0.10), likely due to the small sample size. Painful palmoplantar nodules are an under-recognized presentation of necrobiotic disorders. Although transient, they are often associated with recurrence and systemic diseases, more so if the histopathology is consistent with PNGD. Such patients can be appropriately counselled and evaluated for systemic diseases.