GOECP/SEOR radiotherapy guidelines for thymic epithelial tumours

Table 2 Characteristic clinical manifestation of thymomas and differential diagnosis with other causes of mediastinal masses

	Speed of development	Associated clinical manifestations	Characteristic signs
Thymoma	Long course or indolent	Compressive symptoms: Chest pain, dyspnea, dysphagia, vena cava syndrome	Laboratory abnormalities: Anti-acetylcholine receptor antibodies (common if associated with MG), hypogammaglobulinemia, erythropenia, pancytopenia
		Neurological autoimmune disorders: MG, myotonic dystrophy, limbic encephalitis, peripheral neuropathy
		Hematologic autoimmune disorders: Red-cell aplasia, pernicious anemia, erythrocytosis, pancytopenia
Thymic carcinoma	Rapid growth	Collagen autoimmune disorders: Systemic lupus erythematosus, rheumatoid arthritis, Sjogren's syndrome, scleroderma	PET-CT: Thymoma types A, AB, B1-2: Low uptake.
		Endocrine disorders: Multiple endocrine neoplasia, Cushing's syndrome, thyroiditis	PET-CT: Type B3 thymoma and thymic carcinoma: High uptake, with loss of bilobar structure of the thymus
		Autoimmune deficiencies: Hypogammaglobulinemia, T-cell deficiency
Lymphoma	Fulminant onset	Dermatological disorders: Pemphigus, Lichen planus	Elevated LDH
		“B” symptoms: Fever, weight loss, sweating
Teratoma	Slow development	Lymphadenopathy. Asymptomatic or compressive symptoms of long duration	CT: Heterogeneous mass, with cystic component and fat/calcifications
Germ cell tumors	Rapid development	Testicular mass	Seminoma: Elevated beta-HCG
			No seminoma: Elevated beta-HCG and AFP
Thymic hyperplasia	Indolent	Asymptomatic	PET-CT: Elevated uptake in mass that maintains the thymic bilobar structure

MG: Myasthenia gravis; PET-CT: Positron emission tomography-computed tomography; LDH: Lactate dehydrogenase; HCG: Human chorionic gonadotropin; AFP: Alpha fetoprotein.