Pathology of Mediastinal Disease Flashcards
Portion of the thoracic cavity located between pleural cavities
Mediastinum
traumatic perforation of the esophagus
Acute Mediastinitis
Ruptured esophagus due to sudden increase in intraesophageal pressure and negative intrathoracic pressure caused by retching; common in alcoholics
Boerhaave’s syndrome
- Descent of infection from within the neck
- Spread from chest wall or after heart surgery
Chronic mediastinitis
Anterior Mediastinum
Can produce compression SVC
Common causes; granuloma, fibrosis or both
May be mycotic or tuberculosis in etiology
Tumors, masses, and non neoplastic diseases in the SUPERIOR MEDIASTINUM
Lymphoma - thymus contains lymph nodes
Thymoma - Thymus located in this area as a baby
Thyroid Lesions -thyroid sometimes fails to migrate upward, leading to a low-lying/ectopic thyroid -.plunging thyroid
Metastatic carcinoma
Parathyroid tumors
Tumors, masses, and non neoplastic diseases in the ANTERIOR MEDIASTINUM
Thymoma Teratoma - usually in the midline Lymphoma Thyroid Lesions Parathyroid lesions
Tumors, masses, and non neoplastic diseases in the POSTERIOR MEDIASTINUM
Neurogenic tumors (schwannoma, neurofibroma -benign)
Lymphoma
gastroenteric hernia - esophagus is in this area
Tumors, masses, and non neoplastic diseases in the MIDDLE MEDIASTINUM
Bronchogenic cysts
Pericardial cyst - lined by mesothelium
Lymphoma
Usually at the right cardiophrenic angle
Due to failure of lacunar cavities to merge
Soft and unilocular, contain clear fluid unless infected
Inner surface: flat or cuboidal single layer of mesothelium
Pericardial (Coelomic cysts)
-surgical resection is curative
Small bud or diverticulum carried to the mediastinum by the downward growth of lungs
Foregut cysts
Bronchial - pseudostratified columnar
Esophageal - squamous
gastric and enteric cysts
pancreatic cysts and pseudocysts
Can present as superior mediastinal masses, Arise from cervical thyroid that has been pulled down by enlargement
THYROID LESIONS
Usually found on the anterosuperior compartment
Parathyroid lesions and tumors
small soze, primitive-appearing epithelium without segregation into cortical and medullary regions, presence of tubules and rosettes, absence of Hassal’s corpuscle, almost total absence of lymphocytes
Thymic dysplasia
- Thymus is converted to a multicystic structure
- Thymus shows immature histology
Unilocular thymic cysts
Cyst only has one cavity
Development origin - remants of the 3rd branchial pouch-derived thymopharyngeal duct
Epitheial lining is flattened, cuboidal, columnar or squamous
Acquired process of a reactive nature
Accompanied by inflammation and fibrosis
Lining may be flat, cuboidal, ciliated columnar or squamous; single or stratiied
Multilocular cyst
NON neoplastic diseases
Ectopic thymus
Ectopic parathyroid glands
Acute thymic involution - HIV infection
True thymic hyperplasia - epithelial component of thymus proliferates
Thymic follicular hyperplasia - lymphoid follicles in thymus proliferate
Tumors of thymic epithelial cells
Thymomas
WHO classification of Thymomas
cytologically benign and noninvasive
cytologically benign but invasive or metastatic
cytologically malignant
Account for 20-30% of tumors in the anterosuperior mediastinum
thymomas
Morphology of thymomas
Lobulated, firm gray-white massess up to 15 to 20 cm
Areas of cystic necrosis and calcification’
Most are encapsulated
Noninvasive
Medullary type epithelial cells
Mixture of medullary and cortical type-epithelial cells
Sparse infiltrate of lymphocytes
Cytologically benign but locally invasive
- Much more likely to metastasize
- Cortical Epithelial cells
- Usually mixed with numerous thymocytes
- Cytologic atypia
- 20-25% of all thymomas
- Penetrate through the capsule
Invasive thymomas
5% of thymomas
Fleshy, obviously invasive
Metastasis
Most are SCCAs, next most common lymphoepithelioma-like carcinoma
Thymic carcinoma
Clinical features of thymic carcinoma
impingement on mediastinal structures
MG for all types of thymic tumors
Hypogammaglobulinemia, PRC aplasia, grave’s, PA
NEUROENDOCRINE TUMORS of the THYMUS
Carcinoid tumor - well differentiated
Small Cell Neuroendocrine carcinoma
Large cell neuroendocrine carcinoma
Approximately 20% f the mediastinal tumors and cysts
Germ Cell Tumors
histogenesis is controversial, primary origin from extragonal germ cell is favored
germ cell tumors
also known as germinoma, almost always within thymus, Similar to testicular counterpart; fibrous septa infiltrated by lymphocytes lymphocytes and plasma cella, numerous germinal centers, cells with large amounts of cytoplasmic glycogen
SEMINOMA
Immunolic marker for Seminoma
PLAP and CD 117
Most common type of mediastinal germ cell neoplasm. Can grow to a large size, has a distinct, sharply delineated wall that often becomes calcified,
Cut surface is predominantly cystic
Mature cystic teratoma
Similar to mature teratoma but containing immature epithelial, mesenchymal or neural elements, but most imporantly, the neural element
Immature teratoma
- more aggressive and tends to metastasize
Invasive, highly necrotic neoplasm, Poorly differentiated, Reactive for keratin, PLAP, CD30 and CD57
Embryonal Carcinoma
Admixed with other germ cell elements or as a pure neoplasm. MAy have prominent spindle cell features, contain a hepatoid coponent
Yolk sac tumor
Tumor forms rosette structure around a vessel
Schiller-Duval bodies
COmbination of embryonal carcinoma and teratoma
Teratocarcinoma
Elevated levels of HCG
Extremely poor prognosis
Choriocarcinoma
Malignant lymphoma
Anterior, superior or middle mediastinal mass
Most common primary neoplasm of the middle pportion of the mediastinum
Manifestation of a disseminated process or as a primary mediastinal disease
Hodgkin Lymphoma
Involve the thymus or lymph nodes Young adults, females Local pressure symptoms or found incidentally Nearly always of nodular sclerosis type Polymorphic
binucleate cells, “owl’s eye” appearance
Reed-Sternberg
Particular predilection for the thymic region
Males are commonly affected
Solid, soft, unencapsulated
Involves thymic parenchyma
Lymphocytes with “blastic” appearance - atypical, fine chromatin pattern, nuclear convolutions, mitotic figures
Lymphoblastic Lymphoma
Mass in the thymus, with or without lymph node involvement
Young adult with SVC syndrome
Grossly firm with frequent foci of necrosis
Wide bands of fibrosis, epithelial cells, germ cells, or neuroendocrine neoplasm
Large Cell Lymphoma
