Mediastinal Mass

Local Symptoms 🟢

• Early, non-specific: when the size of a mediastinal mass is still relatively small, early local symptoms are often bothersome but not life-threatening (e.g. cough, dyspnea, chest pain). These symptoms generally don’t bring your attention to the mediastinum; however, the mediastinum should be considered if these symptoms are particularly worse in the supine position (as gravity can augment the irritative compressive effect of an otherwise small mass) or if the patient is very uncomfortable but has no cardiopulmonary dysfunction (i.e. no hypoxemia, no respiratory acid-base issues)

• Late, strategic: as the size of a mediastinal mass grows, strategic anatomic consequences will develop:

… Cardiovascular

• SVC: ↑ JVP, morning facial swelling/cyanosis, orthopnea → stridor

• Thoracic outlet: thoracic outlet syndrome

• Pulmonary artery: pulmonary infarction & hemoptysis

• Right atrium & Right ventricle: cardiac obstructive physiology (e.g. sinus tachycardia)

• Trachea & Mainstem bronchi: focal wheeze

• Esophagus: esophageal dysphagia

• Laryngeal & Phrenic nerves: hoarseness & hiccups, diaphragmatic weakness

• Vagus nerve: neurogenic syncope (cardioinhibitory-type if R. branch, vasodepressor-type if L. branch), sick sinus syndrome, sinus bradycardia

• Brachial plexus: plexopathy, Horner’s syndrome

Systemic Symptoms 🟢

• Early
• B-symptoms

• Late
• HLH

• Thymoma → autoimmune diseases
• Myasthenia gravis
• Pure red cell aplasia
• Autoimmune hemolytic anemia
• Thyroiditis
• Lupus
• Blistering disorders
• Good Syndrome

• Thymic neuroendocrine tumor → endocrine diseases
• Cushing’s
• Carcinoid syndrome

Germ Cell 🟢

• Germ cell → β-hCG
• Thyrotoxicosis (↓ TSH, ↑ FT4/FT3)
• Gynecomastia in males

Diagnostic Spotlight 🟢

• While the list of mediastinal masses is quite long, memorization of that list is far less important than recognition of mediastinal pathology to begin with. To understand the path to this problem, it helps to start with review of…

Anatomy 🟢

• Mediastinum: an intra-thoracic space bordered by the sternum (anteriorly), spine (posteriorly), lungs (bilaterally), thoracic outlet (superiorly), & diaphragm (inferiorly). Can be further subdivided into 3 compartments based on AP landmarks

• Symptoms due to local effects in these compartments are reviewed in Signature ✍️

Epidemiology 🟢

• Base rate favors the anterior compartment DDx. (~50% of mediastinal masses, which is thankfully easy to remember since its the first compartment of the 3!) Of the anterior masses, lymphomas (both Hodgkin & NHL) & thymomas are most common

Physical Exam 🟢

• The “Pemberton maneuver” refers to flexion of the bilateral forearms 180 degrees to the head. Its purpose is to increase the pressure of the thoracic outlet, thereby worsening any pre-existing obstruction of the SVC & resulting in ↑ facial swelling/cyanosis

• @CPSolvers

• @MadellenaC

• Thymoma and autoimmunity

• A Case of Neurally Mediated Syncope and Sick Sinus Syndrome Associated With Lung Cancer

• A rare case of dysphagia and palpitation caused by the compression exerted by an enormous mediastinal lipoma

• Obstructive Shock, from Diagnosis to Treatment