BackgroundPsoriasis is usually diagnosed clinically, so only non‐classic or refractory cases tend to be biopsied. Diagnostic uncertainty persists when dermatopathologists encounter features regarded as non‐classic for psoriasis.ObjectiveDefine and document classic and non‐classic histologic features in skin biopsies from patients with clinically confirmed psoriasis.MethodsMinimal clinical diagnostic criteria were informally validated and applied to a consecutive series of biopsies histologically consistent with psoriasis. Clinical confirmation required 2 of the following criteria: (1) classic morphology, (2) classic distribution, (3) nail pitting, and (4) family history, with #1 and/or #2 as 1 criterion in every caseResultsFifty‐one biopsies from 46 patients were examined. Classic features of psoriasis included hypogranulosis (96%), club‐shaped rete ridges (96%), dermal papilla capillary ectasia (90%), Munro microabscess (78%), suprapapillary plate thinning (63%), spongiform pustules (53%), and regular acanthosis (14%). Non‐classic features included irregular acanthosis (84%), junctional vacuolar alteration (76%), spongiosis (76%), dermal neutrophils (69%), necrotic keratinocytes (67%), hypergranulosis (65%), neutrophilic spongiosis (61%), dermal eosinophils (49%), compact orthokeratosis (37%), papillary dermal fibrosis (35%), lichenoid infiltrate (25%), plasma cells (16%), and eosinophilic spongiosis (8%).ConclusionsPsoriasis exhibits a broader histopathologic spectrum. The presence of some non‐classic features does not necessarily exclude the possibility of psoriasis.