DISEASES OF THE MEDIASTINUM
MEDISTINUM
Mediastinal boundaries
Mediastinal divisions: superior and inferior compartments
The latter is divided into anterior, middle and posterior compartments
Mediastinal Diseases
Classification Of Mediastinal Diseases
Non neoplastic lesions
Neoplastic lesions
Anterior mediastinal disorders
Thymic disorders
Thymoma, thymic carcinoma
Thymic carcinoid
Thymolipoma
Thymic cyst
Thymic hyperplasia
Thyroid disorders
Intrathoracic goiter
Germ cell tumors
Teratoma
Seminoma
Others
Lymphoma
Hodgkin’s disease
Non-Hodgkin’s
Parathyroid adenoma
Mesenchymal tumors
Middle mediastinal disorders
Lymphoma
Benign lympadenopathy
Granulomatous disease
Miscellaneous
Metastatic lymphadenopathy
Cysts
Bronchogenic cysts
Pericardial cyst
Vascular Lesions
Aneurysm
Hemangioma
Miscellaneous
Diaphragmatic hernias
Pancreatic pseudocyst
Posterior Mediastinal Disorders
Neurogenic tumors
Peripheral nerve
Schwannoma, neurofibroma etc
Sympathetic ganglia
Ganglioneuroma, neuroblastoma ….etc.
Paraganglionic tumors
Pheochromocytoma
Esophageal disorders
Benign tumors
Esophageal diverticulum
Spinal
Lateral thoracic meningocele
Paraspinal abscess
Miscellaneous
Thoracic duct cysts
Inflammatory diseases
Acute mediastinitis
‘Danger space’
Chronic mediastinitis
Mycotic, Mycobacteria TB, Nocardia
Fibrosing mediastinitis
Congenital Cysts
Mediastinal Cysts (other than Thymic)
Pericardial (coelomic) cysts
Pericardial sac is formed by fusion of multiple disconnected lacunae.
Foregut cysts
Bronchial cysts
Esophageal cysts
Esophageal cysts
Gastric and Enteric cysts
The gastric type
The enteric type
Gastroenteric cysts
Pancreatic cysts and pseudocysts
Other Cysts
Thoracic duct cyst: cystic lymphangiomas
Adenomatoid tumor
Thyroid and parathyroid lesions
Thyroid tumors and tumor-like conditions
Parathyroid tumors and tumor-like conditions
Parathyroid cysts
Thymus
Anatomy of Thymus Gland
The cortex
The medulla
The cell
The thymus undergoes normal involution after puberty, although it never disappears completely
Thymic Cysts
Unilocular thymic cysts
Multilocular thymic cyst
Dubois abscesses
Other Non-Neoplastic Diseases
Ectopic thymus
Acute Thymic Involution
Acute thymic involution
Diffuse Thymic Fibrosis
True Thymic Hyperplasia
Thymic Follicular Hyperplasia
Thymic follicular hyperplasia
Myasthenia gravis
Langerhans Cell Histiocytosis
Microscopic appearance
TUMORS OF THE MEDIASTINUM
THYMOMA AND THYMIC CARCINOMACARCINOMA
Classification of Thymic Tumors
Historically
The descriptive scheme
The scheme based on topographic and morphofunctional characteristics
Müller-Hermelink scheme comprises the following 5 types
The World Health Organization (WHO) Classification of Tumors of the Thymus and other thoracic tumors
Thymoma and Thymic Carcinoma
General Features
Thymoma
Location of thymoma
Radiographically
Fine-needle aspiration
Pathologic Features of Thymoma
Grossly
“Microthymomas”
Microscopically
By electron microscopy
Immunohistochemistry
Classification of Thymoma
The subtypes of thymomas included in the WHO classification
Type A Thymoma (Spindle Cell; Medullary)
Type AB Thymoma (Mixed)
Type B1 Thymoma (Lymphocyte-Rich; Lymphocytic; Predominantly Cortical; Organoid)
Type B2 Thymoma (Cortical)
Type B3 Thymoma (Epithelial; Atypical; Squamoid; Well-Differentiated Thymic Carcinoma)
Rare subtypes of thymoma that do not easily fit into the A-B nomenclature include
Micronodular thymoma
Metaplastic thymoma
Microscopic thymoma (nodular hyperplasia)
Cytology
Limitations of the procedure
Thymic Carcinoma
Thymic tumor
Thymic Carcinoma
Differences from other conventional types of thymoma
Diagnosis
Squamous Cell Carcinoma (SCC)
Basaloid Carcinoma
Differential diagnosis
Mucoepidermoid Carcinoma
Lymphoepithelioma-Like Carcinoma
Clear cell carcinoma
Sarcomatoid Carcinoma (Carcinosarcoma)
“Phenotypic switch”, myoid cells, “triton tumor”, metaplastic thymoma
“orthotopic” counterpart
Adenocarcinomas
NUT (midline) carcinoma
Undifferentiated (Anaplastic) Carcinoma
Rare variants of thymic carcinomas
Cervical Tumors of Thymic or Branchial Pouch Derivation
Ectopic (cervical) thymoma
Ectopic hamartomatous thymoma
Spindle epithelial tumor with thymus-like elements (SETTLE
Microscopically
Differential diagnosis: synovial sarcoma
Carcinoma with thymus-like elements (CASTLE)