Subcutaneous Sweet Syndrome

[Erythema nodosum]

Erythema nodosum (EN) is the most frequently occurring form of acute panniculitis. It is characterized by painful red to livid raised nodules or bumps that typically occur symmetrically in the shin area. The cause of EN is often a reaction of the immune system to various triggers including infections, inflammatory diseases or medications. In approximately half of the cases no trigger can be identified. After treatment of the underlying pathology EN is typically self-limiting.

Panniculitis: A Cardinal Sign of Autoinflammation

Panniculitis was first described in the nineteenth century and is characterized by inflammation of the subcutaneous fat. It may be categorized in septal or lobular subtypes, but other histopathological features (e.g., presence of vasculitis, nature of inflammatory infiltrates, characteristics of fat necrosis) are also important for diagnostic purposes. Clinically, panniculitis is characterized by the presence of subcutaneous nodules, and both ulcerative and nonulcerative clinical subtypes have been proposed. In this review, we aimed to describe the occurrence of panniculitis in autoinflammatory disorders (AIDs) and related diseases. Among monogenic AIDs, panniculitis is common in IFN-mediated disorders. Panniculitis is a distinctive feature in proteasome-associated autoinflammatory syndromes (PRAAS), including chronic atypical neutrophilic dermatosis with lipodystrophy and elevated temperature (CANDLE) syndrome and Nakajo-Nishimura syndrome. On the other hand, erythema nodosum corresponds to the most common clinical form of panniculitis and is common in polygenic AIDs, such as Behçet's syndrome, inflammatory bowel disease, and sarcoidosis. Cytophagic histiocytic panniculitis, lipoatrophic panniculitis of children, and otulipenia are rare disorders that may also present with inflammation of the subcutaneous fat. Therefore, panniculitis can identify a specific subgroup of patients with AIDs and may potentially be regarded as a cardinal sign of autoinflammation.

Sweet Syndrome: Clinical Presentation, Malignancy Association, Autoinflammatory Disorders and Treatment Response in a Cohort of 93 Patients with Long-term Follow-up

Sweet syndrome is a neutrophilic dermatosis associated with multiple disorders. This retrospective case-series study of patients with Sweet syndrome in a tertiary hospital in Spain from 2001 to 2021, explores clinicopathological characteristics of Sweet syndrome and variables associated with malignancy, presence of autoinflammatory disorders and differences between histological subtypes. A total of 93 patients were identified: 30% idiopathic, 34% malignancy-associated, 29% reactive to infections or drug-associated, and 6% with an autoimmune/inflammatory condition. Acute myeloid leukaemia was the most common malignancy (16/93) followed by myelodysplastic syndrome (7/93). Patients with acute myeloid leukaemia presented isolated flares, marked cytopaenia and rapid response to treatment, whereas myelodysplastic syndrome followed a chronic-recurrent course. The most frequent associated medications and inflammatory  disorders were filgrastim and hydroxyurea (n = 2);  and inflammatory bowel disease (n = 4). In addition, 3 patients were diagnosed with VEXAS syndrome. Male sex (p = 0.006), fever (p = 0.034), increased erythrocyte sedimentation rate (p < 0.001), anaemia (p < 0.001), and thrombocytopaenia (p < 0.001) were associated with malignancy. Histologically, patients were classified as classic (60%), histiocytoid (22.5%) or subcutaneous (15%), with pain (p = 0.011) and nodules (p < 0.001) being associated with subcutaneous-Sweet syndrome. Sweet syndrome in the context of cytopaenia should alert the presence of malignancy. An  acquired autoinflammatory condition should be explored  in relapsing Sweet syndrome with myelodysplastic syndrome. A minimum follow-up of 6 months is recommended.

Neoplastic or inflammatory? A case report of Sweet syndrome with CD30+ cells in a patient with B-lymphoblastic leukemia

CD30+ cells are typically part of lymphoproliferative disorders but can also be seen in inflammatory dermatoses. We present a case of 47-year-old man with a history of B-lymphoblastic leukemia (B-ALL) who presented with fever, leukocytosis, and papulonodular skin lesions, involving the extremities and trunk. A punch biopsy specimen demonstrated papillary dermal edema with a neutrophilic and histiocytic infiltrate extending into the subcutis. The infiltrate also harbored scattered large cells that were positive for CD30 and demonstrated the immunohistochemical profile of monocytes. A diagnosis of histiocytoid Sweet syndrome with CD30+ cells was made. The case is unique, demonstrating a combination of Sweet syndrome variants with subcutis involvement, histiocytoid morphology, and large CD30+ cells. A prior history of B-ALL and immunohistochemical profile of monocytes with immature morphology broadened the differential diagnosis and added to the diagnostic challenge.

Erythema nodosum following treatment with dasatinib plus chemotherapy in a patient with myeloid blast phase of chronic myeloid leukemia

Erythema nodosum (EN) is a type of panniculitis occurring due to various conditions. It can be associated with certain malignancies or manifest as a side effect of drugs. This article presents a unique case of EN in a patient with chronic myeloid leukemia (CML-blast phase) following dasatinib and chemotherapy. Timely recognition and appropriate management are crucial to alleviate symptoms and consider potential drug-induced etiology.

Cutaneous manifestations of monoclonal gammopathy

Monoclonal gammopathy associated with dermatological manifestations are a well-recognized complication. These skin disorders can be associated with infiltration and proliferation of a malignant plasma cells or by a deposition of the monoclonal immunoglobulin in a nonmalignant monoclonal gammopathy. These disorders include POEMS syndrome, light chain amyloidosis, Schnitzler syndrome, scleromyxedema and TEMPI syndrome. This article provides a review of clinical manifestations, diagnostics criteria, natural evolution, pathogenesis, and treatment of these cutaneous manifestations.

Neutrophilic Infiltrates in Panniculitis: Comprehensive Review and Diagnostic Algorithm Proposal

Neutrophilic infiltrates in panniculitis can be seen in different clinical-pathological entities. There are a "mostly neutrophilic inflammatory infiltrate" in some entities classically defined as neutrophilic panniculitis and already included in algorithms, such as enzymatic panniculitis, infective and factitial ones, erythema induratum, or subcutaneous Sweet syndrome, but there are also other panniculitis where neutrophils are frequently observed such as panniculitis associated with inflammatory bowel disease or rheumatoid arthritis, or drug-induced panniculitis associated with BRAF inhibitors, and finally, some panniculitis are better classified in other panniculitides groups but may present with neutrophil-rich variants, such as the neutrophil-rich subcutaneous fat necrosis of the newborn. We review the main clinical and histopathological features of most of these panniculitides and construct a diagnostic algorithm including these diseases.

Atypical neutrophilic panniculitis as presentation of BCR-ABL1-negative chronic myeloid leukaemia

We report the case of an otherwise healthy 60-year-old man presenting with fever, leucocytosis and a painful swelling of the right calf. We initially performed cultural and cytological examination of the popliteal fossa mass, but the results were disappointingly inconclusive. The subsequent development of several erythematous subcutaneous nodules, rapidly evolving to broad ulcerative lesions, prompted us to reconsider the clinical setting as a whole, which included fever, marked leucocytosis and multiple subcutaneous nodules. A biopsy of the ulcerative lesions finally led to the diagnosis of neutrophilic panniculitis, which was sustained by a hybrid myelodysplastic/myeloproliferative disorder like BCR-ABL1-negative atypical chronic myeloid leukaemia. The patient was initially treated with high-dose intravenous corticosteroids, resulting in a dramatic improvement of the skin lesions and normalisation of blood tests. Azacytidine treatment was subsequently started, and the haematological disease remained stable.

Panniculitis: A summary

The diagnosis of panniculitis is felt to be a confusing topic by some pathologists. This summarical article presents inflammatory diseases of the subcutis in a systematic fashion, based on whether they are centered on fibrovascular septa or the adipose lobules, and whether morphologic vasculitis is present or not. Septocentric, non-vasculitis disorders include erythema nodosum, panniculitis that follows the use of "biological" therapeutic agents, lipodermatosclerosis, post-irradiation panniculitis, morphea profunda, and necrobiosis lipodica profunda. Polyarteritis nodosa and Behçet's disease are the conditions that are based in the subcutaneous septa with vasculitis. Predominantly-lobular panniculitides with no vasculitis include pancreatogenic panniculitis, the panniculitis of alpha-1-antitrypsin deficiency, panniculitis associated with lupus erythematosus and dermatomyositis, subcutaneous Sweet syndrome, eosinophilic panniculitis, factitial panniculitis, cold panniculitis, panniculitis following injections of corticosteroids, lipomembranous (ischemic) panniculitis; sclerema neonatorum and subcutaneous fat necrosis of the newborn, and Rosai-Dorfman disease of the subcutis. Erythema induratum and infectious panniculitis are vasculitic and lobulocentric conditions. This article reviews the histological features of these diseases.

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.

Rituximab for refractory subcutaneous Sweet's syndrome in chronic lymphocytic leukemia: A case report

Sweet's syndrome is a neutrophilic dermatosis characterised by sudden onset of fever, neutrophilia, erythematous skin rashes and neutrophilic infiltration of the dermis. Subcutaneous Sweet's syndrome, or Sweet's panniculitis, is an uncommon variant of the classic syndrome, with hypodermal neutrophilic infiltration. The association of Sweet's syndrome with various malignancies has been reported. The most common underlying hematological malignancies are of myeloid origin; however, there have been several reports of the classic Sweet's syndrome in patients with a lymphoproliferative disorder, although the association of subcutaneous Sweet's syndrome with lymphoproliferative disorders has not been well-documented thus far. Herein, we present the case of a 48-year-old man with a 2-year history of chronic lymphocytic leukemia who developed fever and skin rashes, without any evidence of a relapse. The clinical and pathological investigation resulted in the diagnosis of subcutaneous Sweet's syndrome. The patient exhibited no significant response to conventional therapeutic measures; however, following two subsequent doses of rituximab, his general condition and skin rash improved. The follow-up skin biopsy demonstrated dermal neutrophilic infiltrations in conjunction with prior mixed lobular and septal panniculitis, suggesting evolution of subcutaneous Sweet's syndrome to its classic form. To the best of our knowledge, this is one of the first reports of rituximab as a novel biological treatment for Sweet's syndrome. However, further randomized trials are required to evaluate the efficacy and safety of such biological therapies for Sweet's syndrome.

Concurrence of Sweet's syndrome, pathergy phenomenon and erythema nodosum-like lesions

We report the case of a 54-year-old woman with concurrent Sweet's syndrome, pathergy phenomenon and eythema nodosum-like lesions associated with suppurative tonsillitis. Tender, violaceous and highly edematous papules and plaques were detected on the forearms and legs, some of which were pseudovesicular. Similar edematous papules were detected on the dorsum of the hands at the sites of intravenous injection. Biopsies of a plaque on the forearm and a papule at the site of intravenous injection confirmed the presence of Sweet's syndrome. Multiple, tender, violet-red, subcutaneous erythematous nodules were revealed on the legs. A biopsy taken from a nodule on the leg revealed septal panniculitis. To our knowledge, no patient with concurrent Sweet's syndrome, pathergy phenomenon, and erythema nodosum-lesions had been reported yet in previous literature.

Neutrophilic panniculitis: algorithmic approach to a heterogeneous group of disorders

CONTEXT

Neutrophilic panniculitis encompasses an etiologically and morphologically heterogeneous group of disorders. Correct histopathologic diagnosis is important in identifying certain systemic diseases and guiding appropriate treatment.

OBJECTIVE

To review the clinical and histopathologic features of different types of neutrophilic panniculitis, and to provide a diagnostic algorithm for these disorders.

DATA SOURCES

A review of the literature with emphasis on the distinguishing features of different entities was performed.

CONCLUSIONS

Evaluation for neutrophilic panniculitis entails paying close attention to the pattern of inflammation, the type of fat necrosis present, any evidence of vascular damage, and other relevant histopathologic features. An algorithmic approach integrating all histopathologic, clinical, and laboratory findings is required for correct diagnosis.

Subcutaneous histiocytoid sweet syndrome associated with crohn disease in an adolescent

We report a case of subcutaneous histiocytoid Sweet syndrome in an adolescent with Crohn disease. A 14-year-old boy with a 1-year history of ileocolonic and perianal Crohn disease, treated with infliximab and azathioprine, was admitted to the Pediatrics Department with malaise, abdominal pain, bloody diarrhea, and fever (39°C) from 15 days ago. Two days later, he developed cutaneous lesions consisting of tender, erythematous, and violaceous papules and nodules scattered over his legs, soles, and upper extremities. Laboratory studies revealed neutrophilia, microcytic anemia, and elevation of both erythrocyte sedimentation rate and C-reactive protein rate. A skin biopsy specimen showed deep dermal and predominantly septal inflammatory infiltrate in the subcutaneous tissue composed of polymorphonuclears, eosinophils, and mononuclear cells of histiocytic appearance. These histiocytoid cells stained positive for myeloperoxidase. Subcutaneous Sweet syndrome is a rare subtype of acute neutrophilic dermatosis, in which the infiltrate is exclusively or predominantly located in the subcutaneous tissue, causing lobular or septal panniculitis. It is often described in patients with an underlying haematological disorder or caused by drugs, but very rare in patients with inflammatory bowel disease, especially in childhood or adolescence. To our knowledge, this is the first case of subcutaneous histiocytoid type in a paediatric patient.

Sweet's syndrome: clinicopathological features of patients treated from 1997 to 2009 at Cassiano Antonio Moraes University Hospital - Vitoria (Espirito Santo)

Sweet's syndrome or acute febrile neutrophilic dermatosis is rare in Brazil. It is clinically characterized by painful erythematous nodules, papules or plaques that occur mainly on the neck and upper limbs. Its cause may be unknown (idiopathic form) or it may be associated with malignancies, usually hematologic, or drugs. The authors describe 16 cases of the syndrome. The median age was 36 years, and all patients were white and presented solid lesions, predominantly on the upper limbs and trunk. Histopathological examination of the dermis of all patients revealed predominance of moderate to intense, superficial and deep, diffuse inflammatory infiltrate, mainly consisting of polymorphonuclear neutrophils, with leukocytoclasia. It also revealed changes in the epidermis and hypodermis (neutrophilic hypodermitis), but with no signs of vasculitis in most patients, which was not considered an important finding for diagnosis. Presence of exocytosis of neutrophils was common, favoring the diagnosis of Sweet's syndrome when accompanied by diffuse interstitial neutrophilic dermatitis.

Skin manifestations of inflammatory bowel disease

Inflammatory bowel disease (IBD) is a disease that affects the intestinal tract via an inflammatory process. Patients who suffer from IBD often have diseases that affect multiple other organ systems as well. These are called extraintestinal manifestations and can be just as, if not more debilitating than the intestinal inflammation itself. The skin is one of the most commonly affected organ systems in patients who suffer from IBD. The scientific literature suggests that a disturbance of the equilibrium between host defense and tolerance, and the subsequent over-activity of certain immune pathways are responsible for the cutaneous disorders seen so frequently in IBD patients. The purpose of this review article is to give an overview of the types of skin diseases that are typically seen with IBD and their respective pathogenesis, proposed mechanisms, and treatments. These cutaneous disorders can manifest as metastatic lesions, reactive processes to the intestinal inflammation, complications of IBD itself, or side effects from IBD treatments; these can be associated with IBD via genetic linkage, common autoimmune processes, or other mechanisms that will be discussed in this article. Ultimately, it is important for healthcare providers to understand that skin manifestations should always be checked and evaluated for in patients with IBD. Furthermore, skin disorders can predate gastrointestinal symptoms and thus may serve as important clinical indicators leading physicians to earlier diagnosis of IBD.

Bullous Variant of Sweet's Syndrome after Herpes Zoster Virus Infection

AIM

Cutaneous manifestations of Sweet's syndrome (SS) are typically painful plaque-forming erythematous papules, while bullae are quite uncommon. We present a case of bullous variant of SS in acute myeloid leukaemia. In this case, herpes infection of the left mandible had preceded the development of SS.

CASE REPORT

A 75-year-old male with myelodysplastic syndrome first presented with herpes zoster virus infection-like bullae and erosive plaques on the left side of the face and neck. Treatment with valacyclovir and antibiotics was effective only for the initial lesions, whereas the other bullae kept developing predominantly on the left side. Histopathological study revealed epidermal bulla formation, pandermal neutrophilic infiltration, erythrocyte extravasation and subepidermal oedema, but no vasculitis. The findings suggested the diagnosis of bullous variant of SS.

DISCUSSION

Our case was unique in that bullous SS symptoms developed predominantly on one side of the cheek and neck where the herpes zoster infection occurred prior to SS. The tendency may explain the possible association between viral infection and development of SS.

Early pancreatic panniculitis associated with HELLP syndrome and acute fatty liver of pregnancy

Pancreatic panniculitis represents a rare cutaneous disorder most commonly associated with acute or chronic pancreatitis or pancreatic carcinoma. We describe a case of a 17-year-old woman who presented with a 2-day history of erythematous patches involving her bilateral knees and tender, scattered red-brown nodules involving her bilateral anterior shins. She was seen during a hospitalization for emergent cesarean section and her hospital course was complicated by HELLP syndrome (defined by the presence of hemolysis, elevated liver enzymes, low platelet count), acute fatty liver of pregnancy and pancreatitis. The characteristic histopathologic findings, including ghost cells, fat necrosis and granular basophilic material with dystrophic calcification, appear in later lesions. In early lesions, as was shown in this case, a neutrophilic subcutaneous infiltrate raises a differential diagnosis including infection, subcutaneous Sweet's syndrome or atypical erythema nodosum. To our knowledge, this represents the first report of pancreatic panniculitis in association with HELLP syndrome and acute fatty liver of pregnancy. Early recognition is critical, as skin lesions may precede the development of pancreatitis. Often, as in our case, the effects of pancreatitis may be life threatening.

A Case of Sweet's Panniculitis Associated with Spinal Metastasis from Prostate Cancer

Sweet's panniculitis is a rare variant of Sweet's syndrome in which neutrophilic infiltrate can be found either in the subcutaneous fat or in both the dermis and the subcutaneous tissue. Due to the rarity of this entity, the association between Sweet's panniculitis and malignancies is inconclusive, but cases of Sweet's panniculitis have largely been associated with hematological malignancies. Herein, we present a case of Sweet's panniculitis accompanied by bone metastasis from prostate cancer. Clinicians should be aware that Sweet's panniculitis may be associated with malignancies of solid organs.

F-18 FDG PET/CT in the diagnosis of fever of unknown origin

METHODS

The utility of Fluorine-18 fluorodeoxyglucose positron emission tomography/CT in identifying the causal source was assessed in this retrospective study. A total of 68 patients (33 men, 35 women; age range, 23-91 years) with fever of unknown origin (FUO) underwent a positron emission tomography/computed tomography (PET/CT) scan. PET/CT was considered helpful when abnormal results allowed an accurate diagnosis, based on histopathology, microbiologic assays, or clinical and imaging follow-up.

RESULTS

PET/CT demonstrated suspected pathologic foci of Fluorine-18 fluorodeoxyglucose (F-18 FDG) uptake in 41 patients (60%), in 38 of these 41 patients (93%) F-18 FDG PET/CT helped in identifying the causal source, including infection in 25 patients, inflammation in 11 patients, a benign neoplasm in 1 patient, and in 1 patient rejection of a pancreas transplant. In 27 negative F-18 FDG PET/CT studies, no focal pathologic disease was diagnosed in the follow-up. In 6 of these 27 patients, a systemic disease without a focal manifestation was the cause for FUO. In the remaining 21 patients, fever and other signs subsided during follow-up.

CONCLUSION

Overall 56% of the F-18 FDG PET/CT studies contributed in the identification of the source in patients with FUO, and elevated erythrocyte sedimentation rate and C-reactive protein (positive predictive value 93%). When systemic diseases are excluded F18-FDG PET/CT has a high negative predictive value for focal etiologies of FUO (negative predictive value 100%).

Sweet Syndrome due to Myelodysplastic Syndrome: Possible Therapeutic Role of Intravenous Immunoglobulin in Addition to Standard Treatment

We report an 82-year-old lady who developed sudden onset nodular and erythematous lesions and neutrophilia following an episode of urinary tract infection. Skin biopsy confirmed the diagnosis of Sweet syndrome. Response to the use of prednisolone alone was not satisfactory. The skin lesions however showed a sustained response to the regular use of intravenous immunoglobulin (IVIG) and prednisolone was slowly weaned off. Our case highlights the possible therapeutic role of IVIG in managing this condition.

Panniculitis Ossificans of the Lower Leg

The authors present a rare case of panniculitis ossificans (PO) in a 30-year-old woman. Differential diagnoses and treatment are discussed. PO is an important differential diagnosis to sarcomas.