Delphi Panel for the Development of Diagnostic Criteria for Metastatic Cutaneous Crohn Disease: A Consensus Statement.

Importance: Metastatic cutaneous Crohn disease (MCD) is a rare condition for which there are currently no published diagnostic criteria. Formal MCD diagnostic criteria will expand clinical care and research by enabling future diagnostic code validation, crystallizing a more uniform disease entity for the purposes of translational research, and allowing the development of more formalized outcome measures aimed at treatment response.

Objective: To define a set of criteria for the diagnosis of MCD.

Evidence review: In this consensus statement, a panel of experts on MCD and related conditions was assembled. Their opinions were gathered regarding the clinical and histologic findings that are sufficient, necessary, and highly suggestive of MCD through serial survey. Subsequent surveys were continued until consensus was achieved. Sufficient was defined as a feature that, if noted, would enable diagnosis of MCD without any other signs, symptoms, or testing. Necessary was defined as a feature that must be present to establish a diagnosis of MCD. Highly suggestive referred to any other features that were indicative of MCD but did not qualify as sufficient or necessary to diagnose MCD.

Findings: Of 24 experts invited, 19 agreed to participate, with a 79% to 100% response rate across 5 rounds conducted. Five patients were also invited to participate, but none opted to participate, citing lack of clinical expertise and time concerns. The experts were all from the US; 5 (26%) have practiced medicine for 0 to 5 years, 5 (26%) practiced for 6 to 10 years, 6 (32%) practiced for 11 to 15 years, and 3 (16%) practiced for more than 20 years. A total of 18 experts (95%) worked in an academic practice setting. There was consensus agreement that MCD could present as oral disease, genital disease, or, rarely, in another location. Consensus was achieved on 2 major and 5 minor criteria for genital/other subtypes of MCD and 5 minor criteria for oral MCD. There was consensus that, while there are some pathological findings that are highly suggestive of MCD, histologic criteria are not necessary for diagnosis.

Conclusions and relevance: A panel of experts reached consensus on the diagnostic criteria for MCD described in this study. These criteria include major and minor clinical criteria, along with histopathological criteria for the diagnosis of genital and oral MCD. This consensus is a crucial step in the diagnosis of and future treatment development for MCD, a rare and clinically understudied condition.