mediastinal masses

Hanan FathyPediatric Nephrology Unit University of Alexandria

A boy frightened of going to bed

8 year old boy presented to his local hospital with a three week history of worsening respiratory symptoms.

He was previously fit and well, had not been febrile, and his only medical history was a recent visit to his general practitioner because he “found it hard to catch his breath at night.”

He was becoming increasingly scared of going to bed at night and his mother was also concerned about some bumps that she could feel on his scalp while stroking his head in bed.

Chest radiograph.

James C et al. BMJ 2009;339:bmj.b2787

©2009 by British Medical Journal Publishing Group

The decision was made to drain in theatre under general anaesthetic what was assumed to be a right sided pleural effusion.

Upon induction, the patient became apnoeic and was difficult to ventilate.

He then became asystolic and cardiopulmonary resuscitation was commenced. Emergency bronchoscopy was required to establish an airway and cardiac output was restored after 20 minutes of cardiopulmonary resuscitation.

Blood tests were undertaken and his initial blood results were as follows:

Haemoglobin 117 g/l (115-155) White blood cell count 6.35×109/l (6.0-18.0) Platelet count 125×109/l (150-450) Lactate dehydrogenase 3406 U/l (432-700) Uric acid 1170 μmol/l (135-320) Urea 8.9 mmol/l (2.5-6.0) Creatinine 95 μmol/l (35-80) Calcium 2.12 mmol/l (2.19-2.66) Magnesium 0.83 mmol/l (0.7-0.95) Phosphate 4.34 mmol/l (1.1-1.75) Albumin 25 g/l (37-56) Alkaline phosphatase 50 U/l (200-495) C reactive protein 80 mg/l (<10)

Computed tomogram of the chest at the level of the great vessels.

James C et al. BMJ 2009;339:bmj.b2787

©2009 by British Medical Journal Publishing Group

REMEMBER Children presenting with large superior anterior mediastinal masses

represent a medical emergency.

Such children are at extremely high risk of tracheal compression leading to respiratory or circulatory compromise.

To minimize the risk of cardiopulmonary arrest, initiating basic airway management—such as sitting the patient upright and avoiding causing unnecessary distress to the patient—is critically important.

If such patients do lose their airway, turning them to the prone position might be life saving as the weight of the mass is lifted off the airway, making intubation and ventilation possible.

Be sure to know….

Respiratory symptoms occur in 40% to 60% of children with mediastinal mass.

High incidence of cardio -respiratory arrest with sedation / general anesthetics.

Some facts about mediastinal masses

Most mediastinal tumors may be asymptomatic (incidental finding) or associated with vague complaints.

The likelihood of malignancy depends on mass location, patient's age, and the presence of symptoms

Some facts about mediastinal masses Malignant masses are found in the anterior, middle, and posterior

mediastinum in approximately 60%, 30%, and 15% of cases, respectively.

Symptoms are present in 80% to 90% of patients with malignant mediastinal tumors at presentation, compared to 46% of patients with benign masses.

Approximately 10% to 15% of patients with myasthenia gravis have a thymoma.

Neurogenic tumors are commonly observed in children.

Lymphoma, chronic lymphocytic leukemia, thymomas, and thyroid tumors tend to occur in adults.

The diagnosis for different mediastinal masses is done step by step

The evaluation of the clinical aspects

The diagnostic imaging (standard chest radiography, ultrasonography, echocardiography, CT scan, MRI, and scintigraphy).

Laboratory data, and serum bio markers.

Endoscopic examinations (mediastinoscopy, thoracoscopy, esophagoscopy, and tracheobronchoscopy),

And lastly, biopsy.

History and Physical History and Physical ExaminationExamination

Age of the patient. In children, neurogenic tumors of the posterior

mediastinum are common. Lymphoma is the second most common mediastinal tumor, usually located in the anterior or middle compartment, and thymoma is rare .

In both adults and children, approximately 25% of mediastinal tumors are malignant rather than benign

12

Airway compression

dyspnoea, stridor, haemoptysis, coughOesophageal compression

dysphagia, odynophagia, weight lossRecurrent laryngeal nerve compression

hoarse voice

Superior vena cava obstructionfacial swelling, headachePlethora , collateral veins

Sympathetic ganglion involvement Horner's syndromemiosis, ptosis, and anhidrosis

Chest wall invasionmyasthenic pain, palpable mass

ptosis, diplopia, dysarthria

Myasthenic symptomseasy fatigability, drooping eyelid,

double vision, dysarthriaConstitutional symptoms of malignancy

weight loss, night sweats, fever.fever, pallor, petechiae, hepatosplenomegaly,

abdominal mass.

Variation in the presentation in mediastinal masses based on the anatomic site with age

Adults ChildrenAnterior mediastinum 54% 43%Middle mediastinum 20% 18%Posterior mediastinum 26% 40%

Laboratory tests Suspected thymoma: CBC and acetylcholine

receptor antibody

Suspected mediastinal goitre: Thyroid function tests

Suspected parathyroid adenoma: Serum calcium, phosphate, and parathyroid hormone

Suspected germ cell tumor: Alpha-fetoprotein and

beta-human chorionic gonadotrophin

Laboratory tests

Suspected phaeochromocytoma: 24-hour urinary metanephrines and catecholamines, and plasma free metanephrines

Suspected neurogenic tumor: 24-hour urinary homovanillic acid and vanillylmandelic acid

Suspected haematological malignancy: CBC and blood film, flow cytometry, HIV serology.

PNMT, phenylethanolamine N-methyltransferase; COMT, catechol-O-methyltransferase;

SULT1A3, monoamine-preferring sulfotransferase.

Radiological tests

Chest x-ray CT scan with intravenous contrast enhancement MRI Trans-oesophageal echocardiogram Barium swallow Testicular ultrasound

Chest X-ray

A CXR often initiates the evaluation of mediastinal disorders but is rarely diagnostic eggshell calcifications, teeth or bones within a mass, air fluid levels).

Approach for diagnosis in x-ray

1. Is the mass actually in the mediastinum or is it in the lung?

2. If in the mediastinum, then in which compartment?

3. What is the differential diagnosis for the mass?

Clues to locate mass to mediastinum

Mediastinal masses are invested by parietal pleura, so will have:

Smooth contour Tapered borders May be seen bilaterally

Masses in the lung parenchyma typically:

Are surrounded by air May contain air

bronchograms Will be on one side only

The following characteristics indicate that a lesion originates within the mediastinum:

Unlike lung lesions, a mediastinal mass will not contain air bronchograms.

The margins with the lung will be obtuse.

Mediastinal lines (azygoesophageal recess, anterior and posterior junction lines) will be disrupted.

There can be associated spinal, costal or sternal abnormalities.

A lung mass abutts the mediastinal surface and creates acute angles with the lung, while a mediastinal mass will sit under the surface creating obtuse angles with the lung (Figure).

Which compartment?Use these signs to help

1. Cervicothoracic sign

2. Thoracoabdominal sign

3. Hilum overlay.

4. Effect on adjacent structures Trachea Ribs

See sharp margin

above clavicle

Click for lateral view


Thisshouldhelp!


Mass “disappears” at clavicle


Can you see the

outline of themass below

the diaphragm?

Thoracoabdominal Thoracoabdominal signsign

Hilum can be seen through mass

Hilum overlayHilum overlay

Thyroid goiter

Trachea is deviated

to left

Summary

Remember the approach:

1. Is the mass actually in the mediastinum or is it in the lung?

2. If in the mediastinum, then in which compartment? Use the signs

3. What is the differential diagnosis for the mass? Use clinical and radiographic clues

CT scan CT helps delineate anatomic location, extent of disease,

tissue invasion, and tissue density.

CT is occasionally diagnostic and is usually sufficient for pre-operative evaluation.

It is useful in imaging associated mediastinal or hilar lymph nodes, distinguishing mediastinal tumors from vascular abnormalities, identifying concomitant parenchymal lung disease, and demonstrating complex or variant anatomy.

Fluid containing masses

Thymic Cyst Thymoma Teratoma Pericardial Cyst Foregut Duplication Meningocoele Neuroenteric Cyst Cystic Lymphadenopathy Lymphangioma

Fat containing masses

Thymolipoma Teratoma (Germ cell tumors) Esophageal lipoma Fat deposition Lipoma Lipoblastoma Liposarcoma Extramedullary hematopoiesis

Magnetic resonance imaging (MRI)

MRI is superior to CT for imaging nerve plexus and blood vessels, distinguishing tissue planes and invasion, and imaging in non-trans axial planes.

MRI is particularly useful when iodinated contrast

is contraindicated, for imaging posterior mediastinal masses and for assessing tissue, vascular, or cardiac invasion.

Thyroid scanning with radioactive iodine can identify and evaluate masses of suspected thyroid origin.

Alternative thyroid imaging modalities are thalium-201 imaging, technetium-99m-sestamibi imaging, Positron emission tomography with 18 fluorodeoxyglucose (FDG-PET), or scintigraphy with radiolabeled octreotide, a synthetic analog of somatostatin.

Technetium-99m-sestamibi imaging is 90–100% sensitive for identifying parathyroid adenomas in the neck and mediastinum and may identify parathyroid carcinomas.

Methionine PET may more accurately localize parathyroid adenomas.

Biopsy techniques Image-guided percutaneous needle biopsy Endoscopes biopsy with or without

ultrasonography Mediastinoscopy Mediastinotomy/Chamberlain procedure Thoracoscopy Open biopsy sternotomy or thoracotomy Bone marrow biopsy Peripheral lymph node biopsy

Superior vena cava syndrome Horner's syndrome Tracheal obstruction Bronchial obstruction Thoracic aortic aneurysm rupture Aortic dissection

Suspected condition Test of first choice

Thoracic aortic aneurysm Transoesophageal echo

Non Hodgkin`s lymphoma peripheral lymph node excision biopsy

Metastatic cancer biopsy

Thymoma CT scan of chest

Aortic dissection Transoesophageal echo,

CT scan of chest with contrast enhancement

Hodgkin`s lymphoma peripheral lymph node excision biopsy

Mediastinal germ cell tumor seminoma

CT scan of chest, abdomen, and pelvis

Suspected condition Test of first choice

Mediastinal germ cell tumor non seminoma


Thymic carcinoma CT scan of chest, abdomen, and pelvis

Primary tracheal tumors CT scan of chest with contrast enhancement

Neurogenic tumor CT scan of chest with contrast enhancement

Thyroid neoplasia CT scan of neck and chest without contrast enhancement

Mediastinal germ cell tumor mature teratoma


Small cell carcinoma lung cancer

CXR

Robotic Resection of Pediatric Chest MassesJohn Meehan, John Lawrence, Laura Phearman, Paula Francis, and Anthony Sandler

The Children’s Hospital of IowaUniversity of Iowa Hospitals and Clinics, Iowa City, IA

PurposeRobotic surgery is a new technology which may broaden the variety of minimally invasive procedures available for pediatric patients. In addition to providing fine-motion filters that eliminate physiologic tremor, robotic instruments can articulate to aid in difficult dissections. Thoracic masses are particularly suited for robotic surgery because the articulating instruments may be capable of circumnavigating around a rigid mass which may be difficult with standard rigid laparoscopic and thoracoscopic equipment. We present our initial results using robotic surgery to resect benign and malignant thoracic masses.

MethodsWe performed surgical resections of chest masses in 5 patients using the Da Vinci 3-arm Surgical Robot (Intuitive Surgical, Sunnyvale, CA). Our version of the Da Vinci has one 3-D 12 mm camera arm and two 5 mm instrument arms. In one case, we used a 5 mm 2-D scope. All patients had pre-operative scans showing a mediastinal mass. Two children had a posterior solid mediastinal mass, 2 had an anterior solid mediastinal mass, and one had a posterior mass extending around the right lung hilum with central necrosis.

Case 1A 2 year old girl had a mass found on chest x-ray for mild pulmonary symptoms. A CT scan showed a superior and posterior right mediastinal mass with small calcifications (Figure 1-1). The mass was adherent to the azygous vein and superior vena cava (SVC). She underwent complete resection using 3 ports; a 12 mm camera port and two 5 mm robot instrument ports (figure 1-2). An intraoperative photo is shown in figure 1-3. She went home on post-operative day #1. Pathology demonstrated a ganglioneuroblastoma. She did not require any further therapy and she has been disease free for 18 months.

Case 3An 11 year old boy presented with fatigue. After an initial chest x-ray showed a large mass, an MRI demonstrated a right anterior mediastinal (figure 3-1) tumor. His beta-HCG and AFP were normal. He underwent resection using 4 ports as shown in figure 3-2. An intraoperative photograph is shown in figure 3-3 during the dissection of the phrenic nerve. In addition to the phrenic nerve, the tumor was adherent to the SVC, right lung, and the heart. The tumor was resected enbloc. Pathology demonstrated a germ cell tumor. He underwent chemotherapy and currently no evidence of recurrence 15 months after resection.

ConclusionsRobotic surgery is a safe and effective method for resecting thoracic masses in pediatric patients. Dissection can be facilitated by the articulated robotic instruments. Considering the rigidity of the chest wall, articulating instruments may prove to be superior in dissecting in the thorax. Further study of this technology is warranted as it may increase the variety of procedures which can be safely performed using a minimally invasive approach.

DiscussionComplete resection of the primary mass was achieved in all patients. No open conversions were required. Subjectively, the articulating instruments allowed dissection of the mass seem superior to standard non articulating minimally invasive instruments. Treacherous areas such as the SVC, azygous vein, pulmonary hilum, phrenic nerve, and heart were dissected with relative ease and no complications occurred. Times for trocar placement are comparable to our thoracoscopic experience and docking times are relatively insignificant.

Figure 1-1Figure 1-3Figure 1-2

Figure 2-1 Figure 2-3Figure 2-2

Figure 5-1

Figure 3-2 Figure 3-3

Case 2A 16 year old athlete had and fevers, fatigue, and cough. She had been on antibiotics with no improvement and eventually developed wheezing and hemoptysis. A CT scan (figure 2-1) revealed a mediastinal mass with multiple loculated fluid collections and compromise of the right mainstem bronchus (arrow). Although lymphoma was initially suspected, an intraoperative biopsy showed inflammation with no evidence of tumor. Due to the bronchus compression, we elected to perform a resection. Approximately 10 cc’s of purulent material was drained from the mass during the resection. Aerobic, anaerobic, and fungal cultures were negative. Special stains for AFB were also negative. Pathological evaluation revealed inflammation and necrosis but a specific etiology was never identified. She went home post-op day #3 and has remained asymptomatic. Subsequent CT scans have remained clear.

Figure 3-1

Case 4A 4 year old boy presented with mild flu-like symptoms. Work up revealed a chest mass unrelated to his complaints (figure 4-1). Complete resection was accomplished using 3 ports; a 5 mm 2-D robot camera port and two 5 mm instrument ports. Pathology revealed a ganglioneuroma.

ERobot Location

Camera

E

Robot Location

Case 5A 17 year old girl presented with cough. Work-up revealed the anterior mediastinal calcified mass with fat shown in figure 5-1. A fine needle biopsy at an outside facility demonstrated a teratoma. Cart position utilizing 4 ports is shown in figure 5-2. The mass was densely adherent to the lung. An intraoperative photo shows a calified portion of the mass (figure 5-3). Pathology demonstrated a mature teratoma. Follow-up scans have shown no evidence of recurrence 6 months after surgery.

Patient

Age Wt.

(kg)

Diagnosis Trocars

Trocar Placemen

t

Docking Time

Robot Time

Total Time

Tumor

Size (cm)

Length

of Stay

Follow-up

1 2 years 13.9

Ganglioneuroblastoma

3 10 min 3 min 56 min 69 min 6.5 x 4.2 x 1.7

1 day 18 mo.

2 16 years

61.7

Inflammatory Mass 4 10 min 3 min 143 min 156 min 6.0 x 4.0 x 2.0

3 days 15 mo.

3 11 years

40.0

Germ Cell Tumor 4 14 min 4 min 131 min 146 min 12.0 x 14.0 x 5.2

1 day* 15 mo.

4 4 years 21.5

Ganglioneuroma 3 18 min 4 min 22 min 44 min 4.0 x 2.0 x 2.5

1 day 13 mo.

5 17 years

70.5

Teratoma 4 8 min 3 min 140 min 151 min 5.6 x 4.7 x 2.9

1 day 6 mo.

Avg. 9.8 years

41.5

- - 12.5 min 3.4 min 98.4 min 113.2 min

- 1.4 days

13.4 mo

Figure 5-3

Figure 4-3

* - The patient with the germ cell tumor was ready for discharge on post-op day #1 but required chemotherapy. Therefore, he was transferred to the oncology service for 2 additional days of inpatient chemotherapy.

Figure 4-1

AccessoryPort

ERobot Location

Camera

InstrumentArms

Figure 5-2

Phrenic NerveRobot Location

Camera

InstrumentArms

Robot Location

E

EInstrumentArms

Camera

mediastinal masses

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