Related Experiment Video
Updated: Jun 26, 2026
05:39
Spontaneous Murine Model of Anaplastic Thyroid Cancer
Published on: February 3, 2023
Polymyositis with atypical pathological features associated with thymic carcinoma
Yumiko Azuma1, Kensuke Shiga, Ryotaro Ishii
1Department of Neurology, Kyoto Prefectural University of Medicine, Kyoto, Japan. y-azuma@koto.kpu-m.ac.jp
Internal Medicine (Tokyo, Japan)
|February 3, 2009
Summary
This study details a rare case of paraneoplastic polymyositis linked to thymic carcinoma. Surgical removal of tumors and subsequent treatment led to complete recovery of muscle weakness.
Area of Science:
- Neurology
- Oncology
- Immunology
Background:
- Polymyositis is an idiopathic inflammatory myopathy characterized by progressive muscle weakness.
- Paraneoplastic syndromes can manifest as neurological disorders in patients with underlying malignancies.
Observation:
- A 66-year-old male presented with proximal muscle weakness and myalgia, with muscle biopsy revealing inflammatory infiltrates and perifascicular atrophy.
- Elevated MHC-I antigen expression on muscle membranes and CD8-positive T-cells indicated a cytotoxic T-cell mediated pathology.
- Mediastinal tumors, diagnosed as thymic carcinoma, were identified via MRI.
Findings:
- The patient's polymyositis was strongly associated with thymic carcinoma, suggesting a paraneoplastic etiology.
- Complete resolution of muscle weakness and normalization of creatine kinase levels occurred post-thymic carcinoma resection and prednisolone treatment.
- Pathological findings supported a diagnosis of polymyositis, distinct from dermatomyositis, due to the absence of skin lesions and specific immune cell markers.
Implications:
- This case highlights the importance of investigating for occult malignancies in patients presenting with inflammatory myopathies.
- Successful surgical and medical management of the underlying thymic carcinoma led to the remission of paraneoplastic polymyositis.
- Understanding the immunopathogenesis of paraneoplastic polymyositis can inform diagnostic and therapeutic strategies for similar cases.
Related Concept Videos
01:14Atypical Pneumonia
Atypical pneumonia, often caused by Mycoplasma pneumoniae, is a form of pulmonary infection that differs from the classical presentation of bacterial pneumonia in both its cause and clinical symptoms. Mycoplasma pneumoniae is a pleomorphic bacterium notable for its lack of a rigid cell wall. This structural characteristic imparts resistance to beta-lactam antibiotics and significantly influences the bacterium’s behavior within the human host.Other pathogens responsible for the disease include...
01:22Myasthenia Gravis ll: Pathophysiology
The disease process of myasthenia gravis begins at the neuromuscular junction, where antibodies attack key proteins needed for muscle activation. This immune reaction weakens signal transmission, leading to the characteristic muscle fatigue and weakness that define the condition.Immune-Mediated DamageIn most individuals, antibodies target acetylcholine receptors (AChRs) on the postsynaptic membrane of muscle cells. By blocking acetylcholine binding, these antibodies prevent the nerve signal...
01:24Graves Disease II: Pathophysiology
Graves’ disease is an autoimmune disorder characterized by the production of thyroid-stimulating immunoglobulins (TSI) that activate TSH receptors, leading to excessive synthesis and release of thyroid hormones (T3 and T4) and resulting in hyperthyroidism.Among all causes of hyperthyroidism, Graves’ disease is the most common and can happen at any age, though it is more frequent in women. It produces a hypermetabolic state with features such as weight loss, tachycardia, tremor, and heat...
01:27Myocarditis II: Clinical Features and Diagnostic Tests
Myocarditis is an inflammation of the heart muscle. The symptoms vary widely, encompassing asymptomatic presentations to severe, acute manifestations.Clinical PresentationAsymptomatic cases: In some instances, myocarditis may be asymptomatic, with the infection resolving without intervention. These cases often go undetected unless discovered incidentally through diagnostic imaging or tests conducted for other reasons.General Early Symptoms: Early symptoms of myocarditis are non-specific and can...
01:20Myasthenia Gravis: Overview and Treatment
Myasthenia gravis is a neuromuscular transmission disorder characterized by weakness and increased fatigability of skeletal muscles. It is an autoimmune disease affecting approximately one in 2000 people, where antibodies against the α1 subunit of nicotinic acetylcholine receptors are produced.
These antibodies interfere with the function of the nicotinic receptors in three ways: by binding to the receptor and disrupting acetylcholine binding; by causing cross-linking of receptors which leads...
These antibodies interfere with the function of the nicotinic receptors in three ways: by binding to the receptor and disrupting acetylcholine binding; by causing cross-linking of receptors which leads...
01:28Graves' Disease I: Introduction
Graves' disease is an autoimmune disorder that causes hyperthyroidism, or overactivity of the thyroid gland. It results from autoantibodies called thyroid-stimulating immunoglobulins (TSIs), which bind to thyroid-stimulating hormone (TSH) receptors, leading to overstimulation of hormone production and a hypermetabolic state.EtiologyAlthough considered idiopathic, Graves’ disease has well-established contributing factors. There is a strong genetic component, with increased prevalence in...