Thymoma-Associated Multiorgan Autoimmunity with Concomitant Good’s Syndrome: A Rare Clinical Presentation

Abstract

Background:
Multisystem involvement with fever, arthritis and gastrointestinal symptoms commonly suggests infection or connective tissue disease. Paraneoplastic multiorgan autoimmunity is uncommon and may pose a significant diagnostic challenge. Thymoma is classically associated with myasthenia gravis and presentations with inflammatory arthritis, chronic diarrhoea, mucocutaneous lesions and unexplained fever are rare manifestations. The coexistence of thymoma-associated multiorgan autoimmunity (TAMA) and Good’s syndrome further adds to the diagnostic complexity and carries an adverse prognosis.

Case Report:

A 42-year-old man presented with three months of intermittent high-grade fever, inflammatory large-joint polyarthritis, chronic non-bloody diarrhoea, mucocutaneous lesions, hyperpigmentation and significant weight loss. Examination revealed fever, hypotension, inflammatory arthritis of knees and ankles, oral ulcers, exfoliative skin lesions and generalized hyperpigmentation. Laboratory evaluation showed elevated inflammatory markers, hypogammaglobulinemia, low serum cortisol and raised fecal calprotectin. Computed tomography performed during evaluation of chronic diarrhoea identified an anterior mediastinal mass. Surgical excision was undertaken, and histopathology confirmed stage IIA thymoma. The clinical picture was consistent with thymoma-associated multiorgan autoimmunity with concomitant Good’s syndrome. Post-thymectomy, the patient showed marked improvement in fever, arthritis, skin lesions, and diarrhoea. Hypogammaglobulinemia and recurrent infections persisted on follow-up.

Conclusion:
This case highlights an unusual presentation of thymoma with concurrent TAMA and Good’s syndrome. Persistent immunodeficiency despite thymectomy showed the irreversible nature of immune dysfunction seen in Good’s syndrome. Early diagnosis of thymoma as an etiological cause of unexplained multisystem autoimmunity is crucial for early diagnosis and appropriate management.