Lymphocytes in Sweet syndrome: A potential diagnostic pitfall

Sweet's Syndrome: An Update

Sweet's syndrome is a serious dermatological disorder characterized by a rapid onset of tender plaques or nodules, fever, joint pain, headache, and oral and genital lesions. According to the clinical features and underlying causes, Sweet's syndrome is divided into three categories, i.e., classical (or idiopathic), malignancy-associated Sweet's syndrome, and drug-induced Sweet's syndrome. It is multifactorial in etiology, and the exact cause is still undetermined. The diagnosis can be confirmed by the routine histopathologic evaluation of skin biopsy from the lesions. The first-line treatment options are topical and systemic steroids. Multiple databases, like Medline/PubMed, Scopus, and Google, were used to identify resources for this literature review. The relevant information was collected from various case reports, case series, reviews, meta-analyses, and large clinical trials reporting clinical description, etiology, diagnosis, and management of Sweet's syndrome. This narrative review aimed to discuss recent understandings related to Sweet's syndrome, both in terms of clinical presentation and management approach.

Neutrophilic Dermatosis of the Hands with Palmar Involvement and Predominant Lymphomononuclear Cell Infiltration

Neutrophilic dermatosis of the hands (NDH) is a rare localized acral variant of Sweet syndrome. NDH predominantly involves the dorsal hands with characteristic dense dermal neutrophilic infiltrate with an upper dermal edema observed on histopathology. Unusual findings like palmar involvement and predominant lymphomononuclear dermal infiltration in our case with NDH, makes it an interesting read.

Recurrent Idiopathic Sweet Syndrome - Case Report and Literature Review

INTRODUCTION

Sweet syndrome (SS), also denominated as acute febrile neutrophilic dermatosis, is a rare disease characterized by the sudden onset of painful, erythematous, firm skin lesions (papules, plaques, and nodules) which show, upon histologic examination, the presence of a diffuse infiltrate of mature neutrophils. The cutaneous manifestation typically involves the face, neck, trunk, and upper limbs and is associated with fever, general malaise, arthralgia.

CASE REPORT

A female patient, 60 years old, attended the Dermatology Clinic due to the appearance of violaceous erythematous-oedematous infiltrated plaques, located on the face, neck, upper limbs, trunk and knees. The onset of the cutaneous manifestation had occurred 2 months prior, accompanied by pain, chills, flares of fever and arthralgia. The onset coincided with the surgical treatment of an umbilical hernia. From the medical history we note that the patient was diagnosed in 2014 with histiocytoid SS. She followed a treatment with methylprednisolone, with positive response, but had many relapses after the discontinuation of treatment. In 2017, due to a new episode, the histopathological examination was repeated, which revealed classical SS. She received treatment with Disulone and Colchicine. She had not been administered any treatment throughout the previous year. Laboratory tests revealed leukocytosis with neutrophils, increased ESR, elevated C4, hyperglycemia. The current histopathological examination revealed lymphocytic SS. Under treatment with methylprednisolone 32mg/day, the evolution was favorable.

DISCUSSIONS

The first case of SS was described by Robert Douglas Sweet in 1964. As known aetiological factors there have been described gastrointestinal and urinary tract infections, pregnancy, inflammatory bowel disease, drugs or malignancies. There have been described cases of SS that appeared after surgical treatment, as in our case, which registered a new outbreak following the umbilical hernia treatment. The histopathological variants of SS described in the literature are: subcutaneous, eosinophilic, histiocytoid, lymphocytic type. The first line-therapy consists in systemic corticosteroids, which induce a fast remission of lesions and general symptoms. Recurrence may occur in approximately 50% of patients and is common in idiopathic or paraneoplastic cases.

CONCLUSIONS

In addition to the neutrophilic infiltrate that is typical for Sweet syndrome, different types of histological manifestations have been described in the literature: subcutaneous, eosinophilic, histiocytoid, lymphocytic. In our case, we noted that the histological profile changed over time, from a histiocytoid SS recorded in 2014, to a classical SS in 2017, followed by the appearance of lymphocytic SS in 2019. Due to the fact that SS can be associated with a numerous other disorders, our patient requires regular monitoring with a view to eliminate them, and potentially to make a diagnosis and initiate early specific treatment.