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Sweet syndrome in patients with Fanconi anaemia: association with extracutaneous manifestations and progression of haematological disease

Sweet syndrome (SS), also known as acute neutrophilic dermatosis, is a disorder characterized by painful erythematous plaques. The classic pathological description of these lesions is a neutrophilic infiltrate to the dermis, however lymphocytic infiltrates and infiltrates to the adipose tissue (panniculitis) have also been described (Vignon-Pennamen et al, 2006; Guhl & Garcia-Diez, 2008). Approximately 25% of cases are associated with an underlying malignant or pre-malignant disorder, most commonly acute myeloid leukaemia (AML) or myelodysplastic syndrome (MDS) (Hospach et al, 2009). Fanconi anaemia (FA) is a genetic disease characterized by chromosomal fragility and an increased risk of haematopoietic disorders including MDS and AML (Alter, 2003). SS in the setting of FA has been reported in five cases in the literature (Baron et al, 1989; McDermott et al, 2001; Chatham-Stephens et al, 2008). We describe seven patients with FA and SS and report a more frequent association than is seen in other premalignant conditions. We also detail a more complex syndrome that is associated with extracutaneous manifestations of SS and with progression of haematological disease. A retrospective chart review was conducted of patients with FA and SS diagnosed between 2000 and 2010 at three institutions. Information was collected on the presentation of SS, haematological disease status, and relevant clinical and pathological data. Haematological disease was characterized based on the WHO MDS classification scheme (Vardiman et al, 2009). In cases where tissue specimens were available, the pathology was reviewed by a central pathologist. Cases were reviewed with the approval of the institutional review board at Memorial Sloan-Kettering Cancer Center (MSKCC). We report seven cases of SS in patients with FA diagnosed between 2000 and 2010 (Table I) including one previously described patient (Chatham-Stephens et al, 2008). The incidence of SS in FA at one institution (MSKCC) was estimated at 12%. Patients were diagnosed with FA at ages 5–16 years (mean, 11 years) but were diagnosed with SS at an older age, ranging from 17 to 36 years (mean, 26 years). All patients exhibited painful erythematous nodular skin lesions (Fig 1A). In addition to cutaneous findings, four patients had lung lesions (Fig 1B) and one patient had a bone lesion. Lesions were often initially thought to be of infectious origin. Diagnostic testing for bacteria, viral, or fungal causes was negative in all cases. None of the lesions responded to antibiotics. Skin biopsies were obtained in six of seven patients. A neutrophilic infiltrate to the dermis or subcutaneous adipose tissue was described in five of six cases. In one case the dermal infiltrate was composed mostly of lymphocytes. Lung biopsies were obtained in all four cases with pulmonary involvement. Specimens were found to have infiltrating neutrophils in two of four cases. Pathology reports on the remaining two cases describe non-specific inflammation. Slides in these cases were not available for further review. Of note, four of six patients who underwent skin biopsy had significant complications from poor wound healing including one patient who required skin grafting. Six of seven patients exhibited progression of haematological disease around the time of presentation of SS. Four patients progressed from MDS to AML, one patient from aplasia to MDS, and one patient from MDS-refractory anaemia to MDSrefractory anaemia with excess blasts. Patients treated with steroids had a partial or complete, but often transient, response. Five of seven patients subsequently underwent haematopoietic stem cell transplantation. In all five cases lesions resolved with the conditioning regimen received prior to transplant. There were no cases of SS relapse after transplant. This report represents the largest cohort of patients described with SS and FA and gives an opportunity to evaluate the unique characteristics of this syndrome in the FA host. The incidence of SS in FA may be markedly higher than the incidence of SS in other haematological disorders. Practitioners caring for patients with FA should have an increased index of suspicion for SS in any patient with skin lesions that do not respond to antibiotic treatment. Additionally, any patient with SS and haematological abnormalities or skeletal abnormalities should be tested for FA. The complication of poor wound healing was significant in this cohort and has not been previously reported. We therefore recommend that, when possible, patients with FA and suspected SS should proceed to steroid treatment without skin biopsy. Our patients had a high incidence of extracutaneous lesions. Extracutaneous manifestations of SS are considered rare but have been reported in bone, lung, and gastrointestinal tract (Baron et al, 1989; Chatham-Stephens et al, 2008). Patients diagnosed with cutaneous SS should be evaluated for other sites of disease. Conversely, as extracutaneous manifestations may precede skin lesions, clinicians should have an increased suspicion for SS in FA patients with inflammatory lesions at any site with no infectious aetiology. Correspondence