Histiocytoid Sweet's Syndrome in the Setting of Myelodysplastic Syndrome.

Acute febrile neutrophilic dermatosis, or Sweet's syndrome, is characterized by tender, edematous papules and plaques, favoring the upper extremities and the head and neck regions. The classic variant of Sweet's syndrome involves a predominantly neutrophilic dermal infiltrate on histopathology. However, histiocytoid Sweet's syndrome has been noted to have a primary histiocytoid mononuclear infiltrate and is typically found in patients with malignancies such as myelodysplasia. This case report discusses the treatment of histiocytoid Sweet's syndrome in an immunocompromised patient with a recent history of Mycobacterium avium complex infection and latent tuberculosis in the setting of myelodysplastic syndrome.

Suspected coexistence of perianal necrotizing sweet syndrome in chronic myelomonocytic leukemia: A case report.

BACKGROUND: Chronic myelomonocytic leukemia (CMML) complicated with Sweet syndrome (SS) is a rare hematological neoplasm. However, cases of concomitant development of perianal necrotizing SS (NSS) have not been reported. CASE SUMMARY: We report a case of a 49-year-old male patient who underwent sequential procedures for hemorrhoids and perianal abscess. He developed postoperative incision infection and was referred to the department where the authors work. Initially, perianal necrotizing fasciitis secondary to incision infection after perianal abscess surgery was suspected. Despite receiving antibiotic therapy and undergoing surgical debridement, deeper necrotic areas formed in the patient's perianal wounds, accompanied by persistent high fever. Blood and fungal cultures yielded negative results. The final diagnosis was corrected to be CMML with suspected concomitant perianal NSS. CONCLUSION: CMML with perianal NSS is a rare condition, often misdiagnosed as perianal abscess or perianal necrotizing fasciitis. Conventional antibiotic therapy and surgical debridement are ineffective in managing this condition.

Sweet or Not? Azathioprine-Induced Sweet Syndrome Mimicking Erythema Nodosum in a Patient With Inflammatory Bowel Disease.

This case report highlights the clinical challenge and need to distinguish Sweet syndrome and erythema nodosum (EN) in a 50-year-old woman with newly initiated azathioprine for inflammatory bowel disease. While she initially presented with clinical features concerning for drug-induced Sweet syndrome, a subsequent histopathological examination confirmed early-stage EN. Both Sweet syndrome and EN share common triggers and therapeutic responses, but have distinctive clinical characteristics. Subtle histologic differences also exist in lesion distribution and depth of infiltration. This case underscores the need for accurate differentiation in patients with inflammatory bowel disease to initiate appropriate management and avoid potential complications.

Sweet syndrome induced by FLT3 inhibitors: case report and literature review.

BACKGROUND: Acute febrile neutrophilic dermatosis, also commonly referred to as Sweet syndrome, is often associated with tumors, infections, immune disorders and medications. FLT3 inhibitor-induced Sweet syndrome is a rare complication. METHODS AND RESULTS: We report a patient with relapsed and refractory acute monocytic leukemia harboring high-frequency FLT3-ITD and DNMT3a mutations. The FLT3 inhibitor gilteritinib was administered for reinduction therapy after failure of chemotherapy with a combination of venetoclax, decitabine, aclarubicin, cytarabine and granulocyte colony-stimulating factor. The leukemia patient achieved remission after 1 month of treatment. However, Sweet syndrome induced by gilteritinib, which was confirmed by skin biopsy, developed during induction therapy. Similar cases of Sweet syndrome following FLT3 inhibitor therapy for acute myeloid leukemia were reviewed. CONCLUSION: Attention should be given to this rare complication when FLT3 inhibitors are used for acute myeloid leukemia therapy, and appropriate treatments need to be administered in a timely manner.

Proteasome inhibitor-associated histiocytoid Sweet's syndrome: Clinical and histological similarities to Nakajo-Nishimura syndrome suggest a potential mechanism.

Histiocytoid Sweet's syndrome (HSS) is a variant of Sweet's syndrome (SS) that clinically resembles SS but differs histologically by infiltrates, predominantly composed of immature cells of the myeloid lineage. Medications such as proteasome inhibitors have been reported to cause HSS but there has been little discussion on the underlying mechanism. Here we report two cases of HSS associated with a proteasome inhibitor. Both patients were on ixazomib for the treatment of multiple myeloma and presented with acute erythematous plaques on the upper half of the body. Pathological findings were consistent with HSS. Similarities between proteasome inhibitor-induced HSS and Nakajo-Nishimura syndrome, an inherited inflammatory disease, can be identified both clinically and histologically, suggesting a potential explanation of the mechanism behind proteasome inhibitor-associated HSS.

Periorbital necrotizing sweet syndrome: A report of two cases mimicking necrotizing soft tissue infections.

Purpose: Two cases are described of necrotizing Sweet syndrome (nSS), a rare variant of acute febrile neutrophilic dermatosis that mimics necrotizing soft tissue infections. Observation: A 74-year-old female with myelodysplastic syndrome (MDS) presented with isolated periorbital nSS that closely mimicked necrotizing fasciitis (NF); she displayed pathergy to debridement, was exquisitely responsive to corticosteroids, and underwent successful first-stage reconstruction of the eyelid with full-thickness skin grafting. A second 40-year-old female patient with relapsed acute myelogenous leukemia (AML) presented with multifocal nSS most prominently involving the eyelid. Positive herpes zoster virus (HSV) PCR and bacterial superinfection complicated the diagnosis. She improved with chemotherapy for AML and corticosteroid therapy. Conclusion: nSS is rare and a high level of clinical suspicion as well as an understanding of its distinguishing features is necessary to avoid undue morbidity. Identification of pathergy, histopathology, microbiology, and clinical context are critical to avoid misdiagnosis of infection.

Comparative immunohistochemical analysis of inflammatory cytokines in distinct subtypes of Sweet syndrome.

Background: A dysregulated immune response has been implicated in Sweet syndrome (SS) pathogenesis; however, cytokine profiles across different conditions associated with SS - including adult-onset immunodeficiency (AOID) due to anti-interferon (IFN)-γ autoantibodies - remain unknown. Objective: To investigate alterations in inflammatory cytokines in skin lesions of distinct subtypes of SS. Methods: Skin biopsies were collected from 42 AOID- and 52 non-AOID-associated SS patients and 18 healthy controls. The comparative immunohistochemical study was conducted using monoclonal antibodies against interleukin (IL)-1ß, IL-6, IL-17, IFN-γ, and tumor necrosis factor-α on paraffin-embedded sections. The quantitative percentage positivity and intensity were calculated using computer-based image analysis. Results: The results showed stronger and more diffuse dermal immunoreactivity for IFN-γ and IL-17 in the AOID-associated (p < 0.001 and p < 0.001, respectively) and non-AOID-associated SS (p < 0.001 and p < 0.001, respectively) groups. However, no significant differences in the levels of these two cytokines were observed between the AOID- and non-AOID-associated SS groups. Increased expression of IFN-γ together with IL-17 was also noted in almost all subtypes among non-AOID-associated SS. Conclusions: These results demonstrate that IFN-γ and IL-17 are implicated in immunopathology of all SS subtypes, including AOID-associated SS, despite the presence of anti-IFN-γ autoantibodies.

Pulmonary coccidioidomycosis mimicking malignancy associated with Sweet's syndrome (acute febrile neutrophilic dermatosis).

A suspicious malignant lung nodule with cutaneous reaction is not always cancer, especially in low risk for malignancy patients. A lung biopsy should be taken into consideration. The associated cause of Sweet's syndrome directs the treatment in each patient.

Steroid reduction-resistant pulmonary involvement with Sweet's syndrome suspected of being vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic syndrome: A case report.

In cases of Sweet's syndrome with pulmonary involvement, fever of unknown origin, and macrocytic anaemia, VEXAS syndrome can be considered in the differential diagnosis. A 67-year-old man who was taking prednisolone for a fever of unknown origin and Sweet's syndrome was referred to us because of an abnormal chest shadow. Computed tomography revealed a nonfibrotic hypersensitivity pneumonitis-like opacity, and blood test results indicated macrocytic anaemia. His pulmonary symptoms spontaneously improved but again exacerbated approximately 1 month later. Methylprednisolone pulse therapy improved his condition, but he had recurring fever flare and pulmonary involvement post-treatment. A peripheral blood UBA1 gene test planned at a specialized institution was not performed, making the diagnosis difficult. We attempted careful tapering of methylprednisolone, but his macrocytic anaemia led to pancytopenia and he unfortunately died of sepsis due to neutropenia.

A Case of Bullous Sweet's Syndrome Associated With Esophageal Adenocarcinoma.

Sweet's syndrome (SS), or acute febrile neutrophilic dermatosis, characteristically presents with fever, dermal neutrophilic infiltrates, and neutrophilia. It typically manifests as tender erythematous plaques; however, various variants are documented, including bullous. Malignancy-associated Sweet's syndrome (MASS) can present as a paraneoplastic syndrome in those with established cancers or with undiagnosed malignancies. We present a 72-year-old male with a three-day history of a progressive bullous, erythematous papular rash starting on his right forearm and spreading to his extremities, trunk, palms, and soles. It was mildly pruritic but nontender. He had no recent febrile illnesses. On examination, the rash was violaceous with tense bullae overlying edematous targetoid papules coalescing into plaques. Histopathologic analysis of punch biopsies from his abdomen and thigh demonstrated dense inflammatory infiltrates of neutrophils, eosinophils, histiocytes, and lymphocytes, suggestive of neutrophilic dermatosis, or Sweet's syndrome. He was treated with prednisone 1 mg/kg with improvement in his cutaneous symptoms, and a malignancy workup was initiated. Blood work showed elevated free kappa, lambda light chains, lactate dehydrogenase (LDH), and C-reactive protein (CRP) levels. A positron emission tomography (PET) scan revealed lesions in the esophagus and kidney. He was referred to Heme/Onc, GI, and Urology. He was diagnosed with esophageal adenocarcinoma stage IIb and a renal mass. He has since completed neoadjuvant chemotherapy and radiation, is s/p robotic Ivor-Lewis esophagectomy with no evidence of residual carcinoma on pathology, and is undergoing surveillance with imaging every three months for his renal mass. This case highlights the importance of rapid identification of MASS and the impact dermatologists can make in getting these patients the potentially lifesaving care they need.

Sweet Syndrome and Neutrophilic Dermatosis of the Dorsal Hands.

Sweet syndrome is a rare cutaneous condition with a broad clinical differential diagnosis. It can be classified into 3 subtypes: classic, malignancy-associated, and drug-induced. There are numerous associated disorders and provoking medications. Uncommonly, it can present as a multiorgan disease and cause significant morbidity. Systemic corticosteroids are the gold standard of treatment and yield rapid improvements in both lesions and symptoms. Nonsteroidal therapies may be effective alternatives, although high-quality comparative data are lacking. Some treatments for Sweet syndrome have paradoxically been implicated in the induction of disease.

The Neutrophilic Dermatoses, or the Cutaneous Expressions of Neutrophilic Inflammation.

Acute febrile neutrophilic dermatosis, or Sweet syndrome, has been described in 1964 and is now considered as a prototypical condition of the group of the neutrophilic dermatoses. Since this time, many clinical conditions have been included in this group and a clinical-pathological classification in 3 subgroups has been proposed. Neutrophilic infiltrates can localize in all internal organs. This defines the neutrophilic disease, which induces difficult diagnostic and therapeutic problems. Autoinflammation is the main pathophysiological mechanism of the neutrophilic dermatoses. There is a special link between myeloid malignancies (leukemia and myelodysplasia) and the neutrophilic dermatoses.

From Histiocytoid Sweet Syndrome to Myelodysplasia Cutis: History and Perspectives.

In 2005, a new histologic variant of Sweet syndrome (SS) has been described and termed histiocytoid SS (HSS). Clinically, patients had a typical SS, but on skin biopsy, the infiltrates were composed of immature nonblast myeloid cells. Nearly 50% of patients with HSS have myelodysplastic syndrome (MDS). HSS may be the first manifestation leading to the diagnosis of MDS. In 2015, a new category of myeloid dermatosis has been proposed, called myelodysplasia cutis, describing the specific skin infiltration by myelodysplastic cells in patients with MDS.