Initially lymphocytic Sweet's syndrome in male patients with myelodysplasia: a distinguished clinicopathological entity? Case report and systematic review of the literature

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.

Sweet Syndrome Associated with Myelodysplastic Syndrome-A Review of a Multidisciplinary Approach

Sweet syndrome (SS) is a rare disease described as a febrile neutrophilic dermatosis with acute onset, the pathogenesis of which has not yet been elucidated. The syndrome is characterized by the sudden onset of erythematous infiltrated papules or plaques located on the upper body and is associated with fever, leukocytosis and neutrophilia. The lesions show a dense dermal infiltration with mature neutrophils. The condition is responsive to systemic steroids. The central nervous system, bones, muscles, eyes, ears, mouth, heart, lung, liver, kidneys, intestines, and spleen may be affected by SS as extracutaneous manifestations. More and more cases have been found to be associated with malignancies, particularly myelodysplastic syndrome, and, less frequently, other hematologic malignancies or solid tumors. Approximately 21% of patients with SS have an associated malignancy and up to 80% of MASS cases are associated with hematological diseases, predominantly myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML). Myelodysplastic syndrome is a clonal disease of the bone marrow characterized by inefficient hematopoiesis, dysplasia of the bone marrow and peripheral cytopenias. Affected patients have a high risk of leukemic transformation. After analyzing later studies and current practical aspects regarding MDS-related SS, we suggest an algorithm for evaluating these patients.

Clonal neutrophil infiltrates in concurrent Sweet's syndrome and acute myeloid leukemia: A case report and literature review

Sweet's syndrome (SS), also known as acute febrile neutrophilic dermatosis is often associated with a hematological malignancy, especially acute myeloid leukemia (AML) and myeloid dysplasia syndrome. Histopathologically, SS is characterized by diffuse infiltrates in the upper dermis, predominantly consisting of mature neutrophils. The origin of neutrophils invading the skin remains unknown. Herein, we report a patient with concurrent acute monoblastic leukemia and SS who initially presented with discrete erythematous papules and nodules on the neck. Single nucleotide polymorphism (SNP) array and next generation sequencing (NGS) revealed a concordant fms-related tyrosine kinase-3 (FLT-3) gene mutation in the bone marrow and skin lesion, indicating that the neutrophilic infiltrates were clonally related to the underlying myeloid neoplasm. This is the first case report of concurrent SS and AML, in which SNP array and NGS analysis were applied to confirm the clonality of the neutrophilic infiltrates.

Successful Treatment of Syndrome of Inappropriate Antidiuretic Hormone Secretion Associated with Neuro-Sweet Disease in Myelodysplastic Syndrome

Sweet disease may occur in several organs, and central nervous system involvement, known as Neuro-Sweet disease (NSD), is rare. The clinical features of NSD include recurrent encephalomeningitis accompanied by fever and erythematous plaques; systemic corticosteroid therapy is highly effective. Syndrome of inappropriate antidiuretic hormone secretion (SIADH) is an important electrolyte abnormality because it can be life-threatening. We describe the first case of SIADH and NSD associated with low-risk myelodysplastic syndrome that was successfully treated with corticosteroids and cyclosporine. The patient has remained stable for 1 year without any recurrence.

Lymphocytes in Sweet syndrome: A potential diagnostic pitfall

BACKGROUND

Patients with Sweet syndrome (SS) have acute onset of cutaneous lesions with characteristic histopathology (dense and diffuse neutrophilic infiltrate, dermal edema, leukocytoclasis and no vasculitis) accompanied by systemic symptoms. Sometimes, only skin lesions with classic histopathologic features are seen. Although SS is considered to be a "neutrophilic dermatosis," lymphocytes are also seen on histological examination.

METHODS

We evaluated the cellular infiltrate in 9 biopsies from SS lesions with routine staining and immunohistochemistry.

RESULTS

Lymphocytes were present in all biopsies in variable amounts, often exceeding the number of intact neutrophils. Prominent fragmentation of neutrophils rendered some biopsies "lymphocyte-rich" on routine histologic evaluation. Myeloperoxidase was helpful in highlighting the inconspicuous neutrophilic fragments in these cases. Lymphocytes were highlighted with immunohistochemistry, and had a CD3+, CD4+, CD20(-) immunophenotype, with rare CD8+ lymphocytes.

CONCLUSION

Awareness of the lymphocytic component of SS is important to avoid diagnostic errors, especially in subcutaneous lesions of SS, in which the lymphocytic infiltrate predominates in the upper parts of the dermis, while the typical neutrophilic infiltrate may be seen only in the deeper dermis and subcutis. The lymphocytic component may potentially help to differentiate lesions of SS from neutrophilic urticarial dermatosis, which has not been reported to contain a significant lymphocytic population.

Histiocytoid Sweet Syndrome Is More Frequently Associated With Myelodysplastic Syndromes Than the Classical Neutrophilic Variant: A Comparative Series of 62 Patients

Histiocytoid Sweet syndrome (H-SS) is a histological variant of Sweet syndrome (SS) differing from classical neutrophilic SS (N-SS) by a dermal infiltrate mainly composed of lymphocytes and histiocytoid myeloperoxidase-positive cells. We aimed to report a large series of H-SS and compare the frequency and type of hematological malignancies associated to H-SS and N-SS. We included 62 patients with a coding histopathologic diagnosis of SS prospectively registered between 2005 and 2014 in the database of our Department of Pathology. Overall, 22 (35.5%) and 40 (64.5%) patients had a histological diagnosis of H-SS and N-SS, respectively. Median age, sex ratio, and cutaneous lesions were similar in the 2 groups. The frequency of extra-cutaneous manifestations was similar (50% vs 37.5%, P = 0.42). Recurrent forms were significantly more frequent in H-SS than in N-SS patients (21% vs 2.5%, P = 0.01). A hematological malignancy was diagnosed in 22 patients, 12 (55.5%) with H-SS and 10 (25%) with N-SS (P = 0.019). Hematological malignancy was of myeloid origin in 8/22 (36.3%) H-SS and 5/40 (12.5%) N-SS patients (P = 0.02), and of lymphoid origin without myeloid component in 4/22 (18.1%) H-SS and 4/40 (10%) N-SS patients (P = 0.35), respectively. One N-SS patient had a hematological malignancy of mixed (myeloid and lymphoid) phenotype. A myelodysplastic syndrome (MDS) was diagnosed in 7/22 (31.8%) H-SS and 1/40 (2.5%) N-SS patients (P < 0.001). Hematological disease was diagnosed before (in 8 H-SS and 3 N-SS patients) or at the time of the occurrence of the cutaneous lesions (in 1 H-SS and 7 N-SS patients). However, in 3 H-SS patients, all with MDS, cutaneous lesions preceded the hematological disease by ≤6 months. In conclusion, H-SS was associated with MDS in one third of patients but also with lymphoid malignancies, and cutaneous lesions could precede the hematological diagnosis in patients with MDS. A complete hematological assessment is mandatory at diagnosis, and monitoring blood cell counts should be recommended for at least 6 months after the diagnosis of H-SS.

Sweet Syndrome: A Review and Update

Sweet syndrome is the most representative entity of febrile neutrophilic dermatoses. It typically presents in patients with pirexya, neutrophilia, painful tender erytomatous papules, nodules and plaques often distributed asymmetrically. Frequent sites include the face, neck and upper extremities. Affected sites show a characteristical neutrophilic infiltrate in the upper dermis. Its etiology remains elucidated, but it seems that can be mediated by a hypersensitivity reaction in which cytokines, followed by infiltration of neutrophils, may be involved. Systemic corticosteroids are the first-line of treatment in most cases. We present a concise review of the pathogenesis, classification, diagnosis and treatment update of this entity.

Chronic relapsing remitting Sweet syndrome--a harbinger of myelodysplastic syndrome

Sweet syndrome (SS) is an acute febrile neutrophilic dermatosis. It has been associated with malignant disease, especially acute myeloid leukaemia (AML), infections, autoimmune disorders and drugs, particularly granulocyte colony-stimulating factor (GCSF). No cause is found in the rest, which are labelled idiopathic. We describe 15 patients with SS, which we believe represent 'immune dysregulation' secondary to myelodysplastic syndrome (MDS). We initially identified 31 patients with SS in a cohort of 744 patients with MDS and 215 with AML seen over a 6-year period (2004-10). The cause in 16 patients could be attributed either to administration of GCSF or chemotherapy. The eruption was brief and resolved spontaneously or following withdrawal of GCSF. Fifteen patients however, had a chronic debilitating illness dominated by the skin eruptions. Diagnosis of chronic relapsing SS was delayed because the pathology was not always typical of classical neutrophil-rich SS and included lymphocytic and histiocytoid infiltrates and bone marrow was not always performed because the relevance of the eruption to MDS was often not immediately appreciated. All these patients had 'low risk' MDS, diagnosed at a median of 17 months (range 0-157) following the diagnosis of SS. We describe a chronic debilitating episodic clinically distinctive skin eruption with features of SS but not always definitive histopathology often associated with immunological abnormalities affecting other systems related to underlying low risk MDS.