Thymoma and staging
Advanced Thoracic Surgery, Akademisyen Kitabevi, ss.175-182, 2021
- Yayın Türü: Kitapta Bölüm / Araştırma Kitabı
- Basım Tarihi: 2021
- Yayınevi: Akademisyen Kitabevi
- Sayfa Sayıları: ss.175-182
- Sağlık Bilimleri Üniversitesi Adresli: Evet
Özet
Thymoma and Staging INTRODUCTION The thymus gland is located centrally in the anterior mediastinum, but its physiological role has not been fully understood to date. Thymomas, which are tumors of the thymus gland, are relatively rare among all neoplasms. Patients with thymic tumors are usually diagnosed shortly after the clinical presentation. Due to the various histological structures of thymomas, there are different approaches to their classification. In this review, we aimed to present thymic neoplasms, their histological types, and staging.EPIDEMIOLOGYIn adults, thymomas and thymic carcinomas are the most common neoplasms of the thymus. The incidence of thymic tumors is higher for thymomas (2.2 to 2.6/million/year) compared to thymic carcinomas (0.3 to 0.6/million/year) [1]. Thymic neuroendocrine tumors are even rarer. Thymomas have been found to occur in all age groups. Most thymoma patients are between 40 and 60 years old, and thymic neoplasms are equally seen in males and females. There is a peak in patients with myasthenia gravis (MG) between the ages of 30 and 40, and a peak in patients without MG between the ages of 60 and 70 (primarily females) [1]. Retrospective studies on anterior mediastinal masses have shown the following distribution of these tumors: thymoma 35%, benign thymic lesions 5%, lymphoma 25% (Hodgkin 13%, non-Hodgkin 12%), benign teratoma 10%, malignant germ cell tumor 10% (seminoma 4%, nonseminomatous germ cell tumor 7%), thyroid and other endocrine tumors 15% [2]. There is no known risk factor, but it may be associated with myasthenia gravis and other paraneoplastic syndromes.CLINICAL PRESENTATIONThymomas can occur at any age. Patients with thymic tumors are relatively evenly distributed among age cohorts, gender, and the presence or absence of myasthenia gravis symptoms [1]. Thymic neoplasms are often found incidentally during imaging in asymptomatic patients or present with local symptoms or paraneoplastic syndrome symptoms. Most cases, especially those in early stages, are usually asymptomatic. Local symptoms are more likely to occur due to mass effect, such as chest pain, cough, shortness of breath, hemidiaphragm paralysis due to involvement of a phrenic nerve, and hoarseness due to involvement of a recurrent laryngeal nerve or superior vena cava (SVC). Approximately 30% of patients initially present with symptoms associated with myasthenia gravis and a mediastinal tumor is detected [1]. Myasthenia gravis is an autoimmune disorder that occurs due to interference with acetylcholine receptors at the neuromuscular junction by autoreactive antibodies. More than half of patients with thymo ma have symptoms consistent with myasthenia gravis. Myasthenia gravis can occur with any type of thymoma, but it is much less common with thymic carcinomas. Patients with myasthenia gravis and thymoma generally present with less advanced disease compared to those without myasthenia gravis, possibly due to earlier diagnosis of neuromuscular symptoms. If a thymoma ruptures spontaneously, acute mediastinal bleeding is rarely seen with severe chest pain and shortness of breath. Thymomas can also be associated with other systemic diseases called paraneoplastic syndromes (Table 1). Myasthenia gravis is the most common accompanying paraneoplastic syndrome.Table 1 Paraneoplastic syndromesNeuromuscular Myasthenia GravisPeripheral NeuropathyPolymyositisDermatomyositisHematological Red Cell AplasiaPernicious AnemiaErythrocytosisPancytopeniaAutoimmune Hemolytic AnemiaLeukemiaMultiple MyelomaImmunodeficiency Systemic Lupus ErythematosusRheumatoid ArthritisSjögren's SyndromeSclerodermaDermatological PemphigusLichen PlanusChronic Mucocutaneous CandidiasisAlopecia AreataEndocrine Multiple Endocrine NeoplasiaCushing's SyndromeThyrotoxicosisOthers Giant Cell MyocarditisNephrotic SyndromeUlcerative ColitisHypertrophic Osteoarthropathy.