Sweet syndrome in a patient with osteosarcoma

Insights Into the Pathogenesis of Sweet's Syndrome

Sweet's syndrome, also known as Acute Febrile Neutrophilic Dermatosis, is a rare inflammatory condition. It is considered to be the prototype disease of neutrophilic dermatoses, and presents with acute onset dermal neutrophilic lesions, leukocytosis, and pyrexia. Several variants have been described both clinically and histopathologically. Classifications include classic Sweet's syndrome, malignancy associated, and drug induced. The cellular and molecular mechanisms involved in Sweet's syndrome have been difficult to elucidate due to the large variety of conditions leading to a common clinical presentation. The exact pathogenesis of Sweet's syndrome is unclear; however, new discoveries have shed light on the role of inflammatory signaling, disease induction, and relationship with malignancy. These findings include an improved understanding of inflammasome activation, malignant transformation into dermal infiltrating neutrophils, and genetic contributions. Continued investigations into effective treatments and targeted therapy will benefit patients and improve our molecular understanding of inflammatory diseases, including Sweet's syndrome.

Sweet syndrome in children

The objective of this study was to describe the clinical features of Sweet syndrome in children. Our study population consisted of seven children diagnosed with Sweet syndrome over a 22-year period. Age, sex, appearance and location of lesions, associated signs and symptoms, past medical history, pathology, and subsequent disease course were documented for each patient. Fever and typical lesions were reported in most of patients in our study. The majority of patients presented with less-typical findings, such as pustules, vesicles, bullae, oral ulcerations, atrophic scars, and evidence of pathergy. Of the seven children in our study, four were found to have a preceding nonspecific upper respiratory or gastrointestinal infection, and two were diagnosed with an underlying hematologic malignancy. Our results suggest that atypical lesions are relatively common in children with Sweet syndrome and that underlying malignancy is associated with a minority of cases of pediatric Sweet syndrome.

Neutrophilic dermatoses in children

The neutrophilic dermatoses are rare disorders, especially in children, and are characterized by neutrophilic infiltrates in the skin and less commonly in extracutaneous tissue. The neutrophilic dermatoses share similar clinical appearances and associated conditions, including inflammatory bowel disease, malignancies, and medications. Overlap forms of disease demonstrating features of multiple neutrophilic dermatoses may be seen. The manuscript attempts to provide an up-to-date review of (i) classical neutrophilic dermatoses, focusing on distinctive features in children and (ii) neutrophilic dermatoses which may largely be pediatric or genodermatosis-associated (Majeed, SAPHO [synovitis, severe acne, sterile palmoplantar pustulosis, hyperostosis, and osteitis] syndrome, PAPA (pyogenic sterile arthritis, pyoderma gangrenosum, and acne), PFAPA (periodic fever with aphthous stomatitis, pharyngitis, and cervical adenopathy), and other periodic fever syndromes, and congenital erosive and vesicular dermatosis healing with reticulated supple scarring).

Sweet syndrome in two children

We report a 9-month-old girl and a 4-year-old boy with acute febrile neutrophilic dermatosis (Sweet syndrome). Both children were febrile, had leukocytosis, and exhibited lesions characteristic of Sweet syndrome. Both had an antecedent infection. Our evaluation and long-term follow-up of these children failed to reveal evidence of underlying malignancy or a chronic systemic illness typically encountered in Sweet syndrome. Of interest, the 4-year-old boy responded to systemic corticosteroids with remission, whereas the 9-month-old infant experienced flaring of the disease on successive attempts to taper the systemic corticosteroids. Systemic corticosteroid usage was associated with alteration in behavior in the 4-year-old and transient growth retardation in the 9-month-old. In both patients, the adverse effects resolved after discontinuation of the corticosteroids.

Neutrophilic dermatosis of the hands: four new cases and review of the literature

BACKGROUND

Isolated or predominantly hand involvement in Sweet's syndrome, pyoderma gangrenosum, or pustular vasculitis is a rare presentation in the spectrum of neutrophilic dermatoses and is often associated with an occult malignancy or other systemic inflammatory disorder. When these disorders occur on the hands, they are often clinically indistinguishable, but they can sometimes be separated histologically by the presence of papillary dermal edema (Sweet's syndrome), ulceration and necrosis (pyoderma gangrenosum), or vasculitis (pustular vasculitis). These distinctions may be arbitrary, however, and reflect differences in the temporal course of the disease and in the degree of inflammation at the time of biopsy.

METHODS

We report four cases of neutrophilic dermatosis affecting the hands and a review of the literature for similar cases.

RESULTS

Of the four patients presented, two had associated carcinomas and one had myelodysplasia in transition to leukemia. The cutaneous symptoms preceded the finding of an occult malignancy. Thirty-two reported cases of neutrophilic dermatoses presenting on the hands showed clinicopathologic features similar to those in our series. Taken together, the mean age at diagnosis was 60.5 years, and 58% of the patients were female. Twenty-five per cent (nine patients) also had myelodysplasia or leukemia, 14% (five patients) ulcerative colitis, 6% (two patients) carcinoma, 6% (two patients) Crohn's disease, and 6% (two patients) seropositive arthritis.

CONCLUSIONS

These cases illustrate the importance of recognizing that neutrophilic dermatoses may present uniquely or predominantly on the hands. This presentation is distinctive, and prompt diagnosis may prevent unnecessary medical or surgical therapy and may lead to the earlier diagnosis and treatment of an associated malignancy or other systemic disorder.