Coexistence of anti-synthetase syndrome, myasthenia and scleroderma: A scarce case report

Introduction. Polyautoimmunity refers to the phenomenon where an individual is affected by multiple autoimmune diseases simultaneously. This condition underscores the complexity of autoimmune disorders and their interconnected nature, often resulting from shared genetic predispositions and overlapping immunological mechanisms. In this report, we present a case that exemplifies the coexistence of myasthenia gravis, scleroderma, and anti-synthetase syndrome in a female patient. The combination of these three distinct autoimmune conditions highlights the challenges faced by clinicians in diagnosis and management. We herein report a case that illustrates the coexistence of myasthenia, scleroderma and anti-synthetase syndrome in a female patient. Case description. A 45-year-old female patient was referred for systemic sclerosis, without respiratory or muscular involvement. Two years later, she presented with dyspnea and muscle fatigue. She had mechanic’s hands and bilateral symmetric proximal muscle weakness. Laboratory investigations revealed CK levels at 995 IU/L and positive anti-PL7 antibodies. Thoracic CT showed diffuse interstitial lung disease. Spirometry demonstrated a restrictive lung disease. The electroneuromyogram (ENMG) showed a myopathic pattern. Diagnosis of anti-synthetase syndrome was established. Treatment was initiated with monthly cyclophosphamide infusions. Seven months later, she presented with left ptosis and worsening dyspnea and muscle fatigue. An intravenous immunoglobulin infusion was administered, than the patient was commenced on mycophenolate mofetil. She showed a slight improvement, than she developed dysphagia. Brain MRI and cerebrospinal fluid were normal. Onconeuronal antibodies were negative. The ENMG did not reveal any decrement, but the acetylcholine receptor antibody level was positive at 1.12 nmol/L. Consequently, with the presence of ptosis, dysphonia and dysphagia, the diagnosis of myasthenia gravis was established. Imaging did not reveal a thymoma. A favorable therapeutic response was achieved with intravenous immunoglobulins and pyridostigmine. Conclusions. Patients with autoimmune diseases necessitate meticulous management and monitoring because they are at risk for developing multiple immune-mediated disorders, either simultaneously or in succession over the course of their illness. This phenomenon, known as polyautoimmunity, can complicate the clinical picture, as overlapping symptoms and disease manifestations may make diagnosis challenging.