Atypical Type A Thymoma Variant Manifesting Polymyalgia Rheumatica

Area of Science:

• Oncology
• Rheumatology
• Thoracic Surgery

Background:

• Thymoma, a tumor of the thymus gland, can rarely present with paraneoplastic syndromes.
• Atypical thymoma variants require careful surgical management due to potential for invasion and metastasis.
• Polymyalgia rheumatica is an inflammatory disorder causing muscle pain and stiffness, typically in older adults.

Observation:

• A 68-year-old male presented with an anterior mediastinal tumor, diagnosed as atypical type A thymoma with pericardial invasion.
• Following thymectomy, the patient developed symptoms consistent with polymyalgia rheumatica.
• Further investigation revealed bone metastasis from the thymoma.

Findings:

• The patient was diagnosed with both polymyalgia rheumatica and thymoma bone metastasis.
• Treatment with oral prednisolone effectively managed the polymyalgia rheumatica symptoms.
• The patient's condition, including symptoms and bone lesion, remained stable for 3.5 years post-surgery.

Implications:

• This case underscores the diverse clinical manifestations of thymoma, including rare paraneoplastic syndromes like polymyalgia rheumatica.
• Early diagnosis and comprehensive management are crucial for patients with atypical thymoma and metastatic disease.
• The successful management of both thymoma metastasis and polymyalgia rheumatica suggests a favorable prognosis with appropriate treatment.