Metastatic Crohn Disease Clinically Reminiscent of Erythema Nodosum on the Right Leg
Cutaneous manifestations are well-recognized complications of Crohn disease (CD) that can be divided into disease-specific and reactive conditions. One of the most common reactive conditions is erythema nodosum (EN), which presents as subcutaneous tender nodules most often on the legs. On the other hand, metastatic Crohn disease (MCD) is a rare cutaneous manifestation of CD defined as the presence of noncaseating granulomas that are not contiguous with the gastrointestinal (GI) tract. The clinical presentation of MCD is variable; however, lesions often are located on the legs and genital region. We report the case of a 21-year-old woman with a 6-year history of CD who presented with MCD clinically simulating EN.
Practice Points
- Metastatic Crohn disease (MCD) may be an initial sign indicating the aggravation of intestinal Crohn disease (CD).
- Metastatic Crohn disease on the legs could be clinically reminiscent of erythema nodosum (EN).
- Physicians should be aware of the possibility of MCD when encountering EN-like lesions on the legs in a CD patient.
Histopathologically, MCD lesions usually are ill-defined noncaseating granulomas with numerous multinucleated giant cells and lymphomononuclear cells located mostly in the dermis and occasionally extending into the subcutis. The cutaneous granulomata are similar to those present in the affected GI tract. Lymphocytes and plasma cells also are commonly present and eosinophils can be prominent.1,2,11 In some cases of MCD, granulomatous vasculitis of small- to medium-sized vessels can be found and is associated with dermal and subcutaneous granulomatous inflammation.8,11,12 Misago and Narisawa13 suggested that granulomatous vasculitis and panniculitis associated with CD is considered to be a rare subtype of MCD. Few cases of MCD presenting as granulomatous panniculitis have been described in the literature.14-16 Our patient presented with lesions that clinically resembled EN; however, the biopsy was more consistent with MCD. The Table summarizes the distinguishing clinical and histopathological features of MCD in our case and classic EN.
Although some authors believe that MCD is not related to CD activity, others assert that MCD lesions may parallel GI activity.1,2 Our patient was treated with systemic corticosteroids, oral metronidazole, and mesalamine to control the GI symptoms associated with CD. Four weeks after treatment, the GI symptoms and skin lesions improved simultaneously without any additional dermatologic treatment. We believe that MCD has the potential to serve as an early marker of the recurrence of CD and can help with the early diagnosis of CD aggravation, though an association between MCD and CD activity has not been confirmed.
Conclusion
We reported a case of MCD that was clinically reminiscent of unilateral EN and associated with GI disease activity. Physicians should be aware of the possibility of skin manifestations in CD, especially when erythematous nodular lesions are present on the leg.
