Generalized Necrobiotic Palisading Granulomatous Follicular Eruption: A Peculiar Pustular Variant of Perforating Granuloma Annulare or an Individualized Disease?

Herein, we report a case of an adult male patient with a chronic and recurrent papulopustular eruption mainly involving the trunk and lower extremities. A dense superficial perifollicular inflammatory infiltrate with palisading necrobiotic granuloma formation and infundibular perforation was observed at the histological examination, with no granulomatous inflammatory infiltrates in deeper areas. The possibility that this peculiar clinicopathological presentation constitutes a case of generalized perforating granuloma annulare (PGA) or an individualized skin condition is discussed. The observation of a pustular follicular generalized PGA represents an exceedingly rare phenomenon and constitutes an infrequent subtype of PGA that can mimic pustular eruptions secondary to many different etiologies. The clinicopathological features of this rare variant may represent a diagnostic challenge, often requiring multiple biopsies to establish a definite diagnosis.