Diminished regulatory T cells in cutaneous lesions of thymoma-associated multi-organ autoimmunity: a newly described paraneoplastic autoimmune disorder with fatal clinical course

Cytotoxic dermatitis: Review of the interface dermatitis pattern in veterinary skin diseases

Interface dermatitis or lichenoid interface dermatitis refers to a cutaneous inflammatory pattern in which keratinocyte cell death is the essential feature. These terms have evolved from the originally described lichenoid tissue reaction. These lesions are the basis for an important group of skin diseases in animals and people where cytotoxic T-cell-mediated epidermal damage is a major pathomechanism. Yet, for largely historical reasons these commonly used morphological diagnostic terms do not reflect the essential nature of the lesion. An emphasis on subsidiary lesions, such as the presence of a lichenoid band, and definitions based on anatomical features, such as location at the dermo-epidermal location, may cause confusion and even misdiagnosis. This review covers historical aspects of the terminology, including the origin of terms such as "lichenoid." The types of cell death involved and the histopathologic lesions are described. Etiopathogenesis is discussed in terms of aberrations of immune/inflammatory mechanisms focusing on cutaneous lupus erythematosus, erythema multiforme, and Stevens-Johnson syndrome/toxic epidermal necrolysis. Mechanisms have most extensively been studied in humans and laboratory animals and the discussion is centered on these species. As interface dermatitis is firmly entrenched in dermatological parlance, rather than using "cytotoxic" as its substitute, the terminologies "interface cytotoxic dermatitis" and "panepidermal cytotoxic dermatitis" are recommended, based on location and extent of epithelium affected.

Loss of epidermal Langerhans cells in psoriasiform lesions of de novo induced or worsened pre-existing psoriasis following uses of immune checkpoint inhibitors

Immune checkpoint inhibitors (ICI), including monoclonal antibodies to programmed death 1, programmed death ligand 1, and cytotoxic T lymphocyte-associated antigen 4, have provided great therapeutic benefits for cancer patients at advanced stages. However, the introduction of ICI frequently results in the development of immune-related adverse events (irAE) through activation of autoreactive T cells. Here, we present three cases of cancer patients with cutaneous irAE, including development of de novo psoriasis and exacerbation of pre-existing psoriasis. Interestingly, these patients shared an altered histological feature characterized by loss of epidermal CD1a⁺ cells, namely Langerhans cells (LC), in the psoriasiform lesions in contrast to "conventional psoriasis" exhibiting unchanged or activated LC. A possible underlying mechanism was that ICI-mediated hyperactivation of effector T cells contributed to aggravation or establishment of psoriasis phenotype, which might be associated with direct cytotoxicity or expulsion of LC from the epidermis.

Multimodal immunotherapy ameliorates myasthenia gravis preceded by thymoma-associated multiorgan autoimmunity

Thymoma-associated multiorgan autoimmunity (TAMA) is a rare autoimmune disorder associated with thymoma that causes a pathology similar to graft-versus-host disease (GVHD) targeting the skin, digestive organs, and liver. Herein, we report the case of a 38-year-old male with myasthenia gravis (MG) preceded by TAMA. The patient developed intractable diarrhea 2 years before admission. Subsequently, dysphagia, dysarthria, and left blepharoptosis were observed. The patient was admitted to the hospital because of fever and dyspnea, was positive for anti-AChR antibody, and chest-computed tomography revealed thymoma, which led to the diagnosis of thymoma-related MG. Biopsied specimens from the sigmoid colon revealed apoptotic colonopathy with lymphocyte-rich lamina propria. Immunohistochemical staining revealed that the infiltrating cells were predominantly labeled with anti-CD3-antibody. The patient did not show skin lesions or liver dysfunction. Therefore, TAMA limited to the gastrointestinal tract was diagnosed. Although TAMA typically has a poor prognosis, immediate multimodal immunotherapy for MG was successful, resulting in a good outcome for TAMA of this case. TAMA is caused by the inability of the thymoma to suppress self-reactive T lymphocytes, which subsequently leads to a disease that is clinically indistinguishable from GVHD. Based on the characteristics of this case, limited gastrointestinal tract involvement in TAMA without lesions in other organs may lead to a favorable prognosis. TAMA cases lacking skin lesions may present with nonspecific gastrointestinal or liver disease. If a patient with thymoma-associated MG has gastrointestinal symptoms such as diarrhea, TAMA should be considered, and the diagnosis should be made early by pathological evaluation of gastrointestinal tissues.

Thymoma-associated multiorgan autoimmunity with cutaneous only presentation: A case report

Thymoma-associated multiorgan autoimmunity disease can be seen in patients with thymomas and presents with features of graft versus host disease. Here, we report a case of a 52-year-old woman with a complex medical history including malignant thymoma, myasthenia gravis, Good’s syndrome, and T cell large granular lymphocytic leukemia who presented with a diffuse pruritic rash ultimately found to be compatible with a cutaneous presentation of thymoma-associated multiorgan autoimmunity disease. The eruption heralded the recurrence of the malignant thymoma and the rash was ultimately found to be resistant to a multitude of therapies except for oral corticosteroids.

Remission of Thymoma on Steroid Therapy in a Patient With Atypical Thymoma-Associated Multiorgan Autoimmunity: A Case Report and Literature Review

In up to 34% of cases, thymoma, itself a rare neoplasm, is accompanied by autoimmune disorders, two of which are thymoma-associated multiorgan autoimmunity (TAMA) and paraneoplastic autoimmune multiorgan syndrome (PAMS). Unfortunately, differential diagnosis between these two entities can be challenging since no strict PAMS definition exists and PAMS can overlap with a subgroup of TAMA patients with skin lesions as leading presentation. We present a case of a 68-year-old woman with a diagnosis of thymoma accompanied by myasthenia gravis, hypothyroidism and GvHD-like mucocutaneous lesions that initially could account to both TAMA and PAMS diagnosis. However, following the exclusion of humoral autoimmunity against components of epithelial cells junction, TAMA was finally established. Interestingly, the introduction of corticosteroid therapy for TAMA symptom management resulted in unexpected partial remission of thymoma with no impact on mucocutaneous lesions. Our case study is an example of two extremely rare phenomena accompanying thymomas: unprecedented TAMA presentation with GvHD-like mucositis, which as we postulate should be placed in the spectrum of TAMA, and tumor remission on steroids.

Autoimmune disorders and paraneoplastic syndromes in thymoma

Thymomas are counted among the rare tumour entities which are associated with autoimmune disorders (AIDs) and paraneoplastic syndromes (PNS) far more often than other malignancies. Through its complex immunological function in the context of the selection and maturation of T cells, the thymus is at the same time highly susceptible to disruptive factors caused by the development and growth of thymic tumours. These T cells, which are thought to develop to competent immune cells in the thymus, can instead adopt autoreactive behaviour due to the uncontrolled interplay of thymomas and become the trigger for AID or PNS affecting numerous organs and tissues within the human body. While myasthenia gravis is the most prevalent PNS in thymoma, numerous others have been described, be they related to neurological, cardiovascular, gastrointestinal, haematological, dermatological, endocrine or systemic disorders. This review article sheds light on the pathophysiology, epidemiology, specific clinical features and therapeutic options of the various forms as well as courses and outcomes of AID/PNS in association with thymomas. Whenever suitable and backed by the limited available evidence, the perspectives from both the thymoma and the affected organ/tissue will be highlighted. Specific issues addressed are the prognostic significance of thymectomy on myasthenia gravis and other thymoma-associated AID/PND and further the impact and safety of immunotherapies on AID and PND relating to thymomas.

Thymoma-Associated Paraneoplastic Autoimmune Multiorgan Syndrome-From Pemphigus to Lichenoid Dermatitis

Introduction: Paraneoplastic autoimmune multi-organ syndrome (PAMS) is a rare clinical condition characterized by variable and heterogeneous clinical phenotypes in the presence of neoplasias which largely depend on the activation of humoral and cellular immune responses. Clinically, these patients present with a spectrum of antibody-driven pemphigus-like lesions to graft-vs.-host-disease-like exanthemas with a lichenoid inflammatory infiltrate in the skin. PAMS is occasionally associated with thymoma, in which altered immune surveillance eventually leads to multiorgan autoimmunity which often includes variable cutaneous symptoms. This disorder is associated with a profound disturbance of peripheral immune tolerance against human autoantigens. Objectives: We here present a patient with relapsing thymoma who developed PAMS with several cutaneous and extracutaneous autoimmune disorders. Materials: Peripheral blood mononuclear cells (PBMC), sera, and lesional skin biopsies were obtained at different clinical disease stages. Peripheral T cell subsets were characterized phenotypically and the cytokine profile of the peripheral blood T cellular response against distinct epidermal and dermal autoantigens of the skin was analyzed by ELISpot assay. Serological screening was performed by ELISA and immunoblot analysis. Skin biopsies were subjected to immunohistochemical analysis of distinct T cell subsets. Thymoma tissue was analyzed for the presence of T regulatory cells and compared with adult thymus and indolent thymoma. Results and Conclusions: In the present case, thymoma was the cause of the observed multi-organ autoimmune syndromes as its recurrence and surgical removal was associated with the relapse and regression of the cutaneous symptoms, respectively. Initially, the patient presented with two autoimmune disorders with Th2/Th1 imbalance, myasthenia gravis (MG) and pemphigus foliaceus (PF), which regressed upon immunosuppressive treatment. Months later, the patient developed a lichenoid exanthema with a Th1-dominated skin infiltrate. Further clinical evaluation revealed the recurrence of the thymoma and the lichenoid exanthema gradually regressed upon thymectomy. Our contention that T cell recognition against distinct cutaneous autoantigens, such as desmoglein 1 (Dsg1), shifted from a Th2 to a Th1-dominated immune response could not be fully substantiated as the patient was on a stringent immunosuppressive treatment regimen. We could only observe a decrease of the initially present serum IgG autoantibodies against Dsg1. Phenotypic analysis of the associated thymoma showed a lower number of T regulatory cells compared to adult thymus and indolent thymoma, suggesting that impaired thymus-derived immune surveillance had a direct impact on the outcome of the observed cutaneous autoimmune disorders.

Concurrent renal amyloidosis and thymoma resulting in a fatal ventricular thrombus in a dog

Thymoma-associated nephropathies have been reported in people but not in dogs. In this report, we describe a dog with thymoma and concurrent renal amyloidosis. A 7-year-old castrated male Weimaraner was presented for progressive anorexia, lethargy, and tachypnea. The dog was diagnosed with azotemia, marked proteinuria, and a thymoma that was surgically removed. Postoperatively, the dog developed a large left ventricular thrombus and was euthanized. Necropsy confirmed the presence of a left ventricular thrombus and histopathology revealed renal amyloidosis. We speculate that the renal amyloidosis occurred secondary to the thymoma, with amyloidosis in turn leading to nephrotic syndrome, hypercoagulability, and ventricular thrombosis. This case illustrates the potential for thymoma-associated nephropathies to occur in dogs and that dogs suspected to have thymoma should have a urinalysis and urine protein creatinine ratio performed as part of the pre-surgical database.

Thymoma-associated multiorgan autoimmunity with exclusive gastrointestinal tract involvement: case report and review of the literature

Thymoma-associated multiorgan autoimmunity (TAMA) is a recently delineated and rare paraneoplastic syndrome reported in patients with thymoma. The disorder is characterized by graft-versus-host disease-like pathology affecting the skin, gastrointestinal tract (GIT), and liver, and is usually associated with a poor outcome. We document a case of TAMA with exclusive GIT involvement which included the stomach, small and large bowel, presenting in a 66-year-old male patient 5 years after complete resection of a type B2 thymoma. A brief review is provided of this scarce syndrome, the GIT pathology described in the 21 TAMA cases reported to date, and the unique characteristics of patients with exclusive GIT involvement by this acquired autoimmune disorder.

Case of thymoma-associated cutaneous graft-versus-host disease-like disease successfully improved by narrowband ultraviolet B phototherapy

Thymoma-associated graft-versus-host disease (GVHD)-like disease is a rare paraneoplastic disease seen in patients with thymoma. Here, we describe the first case of thymoma-associated GVHD-like disease localized to the skin that was successfully improved by a combination of systemic corticosteroids and whole-body narrowband ultraviolet (UV)-B phototherapy. The patient had developed toxic epidermal necrolysis-like erosive skin lesions over the whole body. Although systemic corticosteroids were effective up to a point, we were unable to begin the steroid taper. The addition of systemic narrowband UV-B phototherapy improved the skin manifestation of this disease, allowing corticosteroids to be reduced to a third of the original dose. Histopathologically, it was confirmed that the proportion of Foxp3-positive lymphocytes in the skin increased after narrowband UV-B irradiation. We propose that whole-body narrowband UV-B phototherapy is a good therapeutic option for the skin manifestation of thymoma-associated GVHD-like disease.

Graft-versus-host disease-like erythroderma: a sign of recurrent thymoma: A case report

RATIONALE

Thymomas are associated with numerous autoimmune disorders, such as myasthenia gravis (MG), pure red cell aplasia (PRCA), and systemic lupus erythematosus (SLE). However, graft-versus-host disease (GVHD)-like erythroderma is a relatively uncommon paraneoplastic disorder associated with thymomas and signifies a poor prognosis.

PATIENT CONCERNS

A 35-year-old woman with medical history significant for stage IVa type AB thymoma presented with patchy erythema over face, trunk, and extremities that failed to respond to topical steroids.

DIAGNOSIS

A contrast-enhanced computerized tomography (CECT) scan of the chest demonstrated tumors in the right mediastinum and right pleura. Percutaneous right mediastinal pleural biopsy confirmed recurrent thymoma (WHO type B3, Masaoka stage IVb). Histopathologic examination of her skin lesions revealed GVHD-like erythroderma.

INTERVENTIONS

The patient received chemotherapy and local thoracic radiotherapy, as well as corticosteroids.

OUTCOMES

The eruptions gradually subsided with hyperpigmentation; however the patient eventually died of multiple organ failure.

LESSONS

GVHD-like erythroderma is an uncommon paraneoplastic disorder associated with thymomas. Though its pathogenesis still needs further research, prompt diagnosis and appropriate treatment can improve survival rate in patients.

Thymoma-associated multi-organ autoimmunity: A case of graft-versus-host disease-like erythroderma complicated by Good syndrome successfully treated by thymectomy

Thymoma-associated multi-organ autoimmunity disease (TAMA) is a rare paraneoplastic disorder, clinicopathologically similar to graft-versus-host disease (GVHD). Many reported cases follow a difficult course; half of them die from serious infectious diseases subsequent to immunosuppression induced by chemotherapy for unresectable thymoma, or intensive therapies including systemic steroids for complicating autoimmune diseases and GVHD-like symptoms. We report a patient whose skin symptoms were improved subsequently to total thymectomy. The patient also presented with hypogammaglobulinemia, which led to the diagnosis of complicated Good syndrome. Taking account of her immunodeficient condition, antibiotics and i.v. immunoglobulin were administrated promptly on onset of bacterial pneumonia, which was successfully treated. According to a review of the published work, treatments with systemic steroids for skin symptoms have limited effects and may contribute to serious infection. Our case indicates that successful treatment of thymoma itself may lead to the amelioration of the disease. The management priority should be given to the treatment of thymoma and the control of subsequent immune abnormality other than GVHD-like erythroderma.

Increased frequency of skin-infiltrating FoxP3+ regulatory T cells as a diagnostic indicator of severe atopic dermatitis from cutaneous T cell lymphoma

Differential diagnosis of cutaneous T cell lymphoma (CTCL) and severe atopic dermatitis (AD) is often difficult because of the similarity in their skin manifestations. However, such differentiation is extremely important because of the differences in remedy and prognosis. The aim of this study was to investigate new, helpful diagnostic aids for distinguishing CTCL from AD. The frequency of forkhead box protein 3(+) (FoxP3(+)) regulatory T cells (T(regs)) in cutaneous lesions was evaluated among the three populations. Serum-soluble interleukin-2 receptor (sIL-2R), immunoglobulin (Ig)E-radioimmunosorbent test, lactate dehydrogenase (LDH) and blood eosinophil count were measured in 11 CTCL patients (including three CTCL patients misdiagnosed previously with intractable AD), 10 adult AD patients and nine psoriasis patients. The frequency of T(regs) was increased significantly in cutaneous lesions of AD compared with those of CTCL. Serum IgE and LDH levels were also elevated significantly in AD compared with CTCL, whereas there were no significant differences in serum sIL-2R levels between CTCL and AD. In the three CTCL patients who were misdiagnosed with intractable AD, IgE and LDH levels were lower than in AD patients, whereas serum sIL-2R levels were as high as in AD patients and higher than in the other eight CTCL patients. The higher frequency of T(regs) in the cutaneous lesions of patients with AD than in those with CTCL and higher serum IgE and LDH levels in patients with AD than in those with CTCL might be helpful reference values for the differential diagnosis of these two diseases.

The temporal and spatial dynamics of Foxp3+ Treg cell-mediated suppression during contact hypersensitivity responses in a murine model

Regulatory T (Treg) cells suppress contact hypersensitivity (CHS) responses, but the dynamics, mode, and site of their action is not well characterized. We studied forkhead box P3+ (Foxp3+) Treg cells during the CHS response in conditional Foxp3 knockout depletion of regulatory T cell (DEREG) mice, where Foxp3+ cells can be transiently deleted by diphtheria toxin. The mice were sensitized and challenged with oxazolone, and Foxp3+ cells were depleted either during sensitization or elicitation. Treg cell depletion before sensitization led to significantly exacerbated and prolonged CHS responses. In contrast, depleting Treg cells during elicitation had no effect on the 24-hour response, but the response was significantly prolonged. In wild-type mice, the gradual resolution of the CHS response was accompanied by a similarly gradual accumulation of Foxp3+ Treg cells relative to T effector cells in the skin. This effect was not as marked in the Treg cell-depleted mice, suggesting that the skin is an important site of Treg cell activities during the resolution phase. Together, our results show that endogenous Foxp3+ Treg cell function is important during the sensitization and resolution phases, but their depletion just before elicitation does not have an effect on the CHS response during the first 24 hours after elicitation.