MEDIASTINAL MASSES

Mediastinal Anatomy

Mediastinal Anatomy

Anterior

thymus, aorta, great veins, lymphatics

Middle

heart, pericardium, trachea

Posterior

Esophagus, vagus nerves, thoracic duct, sympathetic chain, azygous venous system

Anterior Mediastinum

Thymoma

Thymoma

Hodgkin’s

Intrathoracic goiter

Anterior Mediastinum

Other thymic tumors - carcinomas, carcinoid tumors, lipomas, cysts

Germ cell tumors

Thyroid tumors

Parathyroid adenoma

Connective tissue tumors - lipomas, liposarcomas, lymphangiomas, hemangiomas

Middle Mediastinum

Pericardial cyst

Bronchogenic cyst

Middle Mediastinum

Thyroid tumor or goiter

Tracheal tumors

Lymphadenopathy 2/2

infection

malignancy

idiopathic

Posterior Mediastinum

Posterior Mediastinum

Most neurogenic tumors

Esophageal tumors

Hiatus hernia

Neurenteric cysts

Unusual: pancreatic pseudocyst, achalasia, extramedullary hematopoiesis

Paraspinal ganglioneuroma

Paraspinal neurilemmoma

Notes

Aortic aneurysms can be located in any compartment

Anterior masses more likely to be malignant

59% vs. 29% vs. 16%, converse is true in children

increased likelihood in 20-40 yo

Most common lesions:

Children - neurogenic tumors, enterogenous cysts

Adults - neurogenic tumors, thymomas, thymic cysts

Signs & Symptoms

Hemoptysis, recurrent pulmonary infection (airway compression)

Dysphagia (esophageal compression)

Paralysis (spinal column involvement)

Elevated hemidiaphragm (phrenic nerve damage)

Hoarseness (recurrent laryngeal involvement)

Horner’s & SVC syndrome (sympathetic ganglion, SVC)

Signs & Symptoms

Associated systemic diseases

Thymoma = myasthenia gravis, immune deficiency, red cell aplastic anemia

Thymic carcinoid tumor = Cushing syndrome

Goiter = thyrotoxicosis

Parathyroid adenoma = hyperparathyroidism

Imaging

CXR -> CT with IV contrast

MRI only recommended if pt has contrast allergy or renal failure

useful for neurogenic tumors

Transesophageal US - posterior lymph nodes

Radionuclide scanning

123-I for thyroid, sestamibi for parathyroid, gallium for lymphomas (replaced by FDG-PET)

Labs

Goiter -> TFTs

Parathyroid adenoma -> Ca, P, PTH

Paragangliomas -> urine metanephrines, catecholamines

Neurogenic tumors -> homovanillic acid, vanillylmandelic acid

Germ cell tumor -> AFP, B-HCG

all male pts with anterior mass

Management

Excision

if likely benign - teratoma, thymoma

needle aspiration, VATS, sternotomy/thoracotomy

Biopsy

lymphoma, germ cell, unresectable malignancy

surgical biopsy preferred over needle aspiration

Chest wall tumor implantation is a rare complication

Complications

Surgical treatment has increased risk of morbidity 2/2 central airway obstruction, greatest in those with:

Cardiorespiratory symptoms

Evidence of tracheal obstruction

Mixed obstructive & restrictive PFTs

The End