MRI findings of neutrophilic fasciitis in a patient with acute febrile neutrophilic dermatosis (Sweet's syndrome)

Recurrent soft tissue inflammation, necrotizing fascitis or Sweet syndrome, diagnostic dilemma

Necrotizing Sweet syndrome is a recently described entity that can pose significant challenges for management. Although necrotizing fasciitis can be rapidly fatal in the absence of prompt surgical management, necrotizing Sweet syndrome may actually be worsened by any surgical intervention. Authors want to emphasize and increase awareness of this rare presentation.

Necrotizing fasciitis and its mimics: what radiologists need to know

OBJECTIVE

The purpose of this article is to review the imaging features of necrotizing fasciitis and its potential mimics. Key imaging features are emphasized to enable accurate and efficient interpretation of variables that are essential in appropriate management.

CONCLUSION

Necrotizing fasciitis is a medical emergency with potential lethal outcome. Dissecting gas along fascial planes in the absence of penetrating trauma (including iatrogenic) is essentially pathognomonic. However, the lack of soft-tissue emphysema does not exclude the diagnosis. Mimics of necrotizing fasciitis include nonnecrotizing fasciitis (eosinophilic, paraneoplastic, inflammatory (lupus myofasciitis, Churg-Strauss, nodular, or proliferative), myositis, neoplasm, myonecrosis, inflammatory myopathy, and compartment syndrome. Necrotizing fasciitis is a clinical diagnosis, and imaging can reveal nonspecific or negative findings (particularly during the early course of disease). One should be familiar with salient clinical and imaging findings of necrotizing fasciitis to facilitate a more rapid and accurate diagnosis and be aware that its diagnosis necessitates immediate discussion with the referring physician.

Acute febrile neutrophilic dermatosis (Sweet's syndrome)

PURPOSE OF REVIEW

To highlight the recent observations regarding not only research but also the clinical features and management of Sweet's syndrome.

RECENT FINDINGS

Some of the new insights concerning Sweet's syndrome include: (1) bortezomib-induced Sweet's syndrome (some of which are the histiocytoid variant), (2) a rare extracutaneous manifestation of Sweet's syndrome with cardiovascular involvement including coronary artery occlusion, and (3) the possibility that photosensitivity may have a role in the pathogenesis of Sweet's syndrome.

SUMMARY

Animal models of Sweet's syndrome and new associated medication have been observed. The definitive mechanism of pathogenesis still remains to be elucidated. Recent observations in paediatric patients suggest evaluation of dermatosis-related cardiac involvement in patients with post-Sweet's syndrome cutis laxa. Treatment advances include antitumour necrosis factor- alpha drugs; however, these medications have also been associated with inducing Sweet's syndrome. Nearly 50 years after the initial description of an acute febrile neutrophilic dermatosis by Dr Robert Douglas Sweet, the dermatosis remains a fascinating condition with regard to laboratory investigation, clinical manifestations and treatment.

Necrotizing Sweet syndrome: a new variant of neutrophilic dermatosis mimicking necrotizing fasciitis

BACKGROUND

We report a series of patients initially given the diagnosis of necrotizing fasciitis whose course progressed despite surgical debridement, antibiotic therapy, or both, but who responded rapidly to systemic corticosteroids.

OBJECTIVE

We sought to evaluate the clinical data, histopathologic and microbiology information, and treatment course of this unusual entity.

METHODS

This was a descriptive study/case series.

RESULTS

Three immunocompromised patients who presented with signs and symptoms of necrotizing fasciitis were included. They appeared septic, failed multiple courses of antibiotics, demonstrated pathergy, and two of them underwent extensive surgical debridement. None of the cases yielded a microbial source. Dermatologic consultation and histopathology confirmed deep Sweet syndrome in all cases, with marked necrosis of the soft tissue--including myonecrosis--in the two patients with debridement. All patients responded rapidly to high-dose systemic corticosteroids.

LIMITATIONS

To our knowledge, this is the first report of this unusual presentation; there are a limited number of cases.

CONCLUSION

We propose that these cases represent a new variant of neutrophilic dermatosis: "necrotizing Sweet syndrome," an acute necrotizing neutrophilic dermatosis. This subtype is also characterized by the rapid onset of progressive erythematous, warm, edematous cutaneous lesions with deep-tissue neutrophilic infiltration and soft-tissue necrosis, in the absence of infectious cause. Awareness of this entity and early dermatologic consultation is critical as debridement results in expansion of the process, resulting in additional and aggressive resection--a vicious cycle with significant possible morbidity.