OVERVIEW OF PRIMARY MEDIASTINAL TUMORS AND CYST

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OVERVIEW OF PRIMARY MEDIASTINAL TUMORS AND CYST

• GENERAL THORACIC SURGERY
• CHAPTER 160

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Mediastinal tumor

• Numerous tumor and cyst occurred in mediastinum.
• Affect all age.
• More common in young and middle-age adult.
• Most mass are discovered on routine radiographic
  examination.
• Benign lesion most asymptomatic, malignant lesion
  most produce clinical finding.

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Mediastinal component

• Anterior compartment.
• Visceral compartment.
• Paravertebral sulci.

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Location of common tumor and cyst

• Anterior mediastinum Thymoma, lymphoma, germ
  cell tumor.
• Visceral compartment Fore-gut cyst,
  bronchogenic cyst, esophageal, and gastric
  origin, secondary tumor of lymph node,
  pleuropericardial cyst, cystic lymphangioma.
• Paravertebral sulci Neurogenic tumor, vascular
  tumor, mesenchymal tumor, lymphatic lesion,
  fibroma, lipoma.

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Signs and symptoms

• child2/3 with symptoms
• Adult 1/3 with symptoms.
• Symptom /sign dependent on benign and malignant,
  size, location, infection, endocrine or
  biochemical products.

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Signs and symptoms

• Infant and child Cough, dyspnea stridor are
  prominent even a small mass, septic complication
  with resultant pneumonitis, fever frequently.
• Adult cough dyspnea, chest pain, s/s related
  infection, obstruction vital structure, invasion
  adjacent structure, pleural effusion, Horners
  syndrome, diaphragm paralysis.

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Benignity versus malignancy

• Adult Less 40 of anterior mediastinal tumor
  are malignant, almost all cyst are benign.
• Child Incident of malignancy is high than
  adult, most malignant tumor are in child less
  than 3 y/o(86), 91 benign lesion in older
  children, 45 lesion in child anterior
  compartment are malignant lymphoma.

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Benignity versus malignancy

• Only small percentage of germ cell tumor in child
  are malignant.
• In visceral compartment Mmany lymph node lesion
  are malignant.

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DIAGNOSTIC INVESTIGATION OF MEDIASTINAL MASSES

• GENERAL THORACIC SURGERY
• CHAPTER 161

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Noninvasive diagnostic procedures

• CT
• MRI
• Ultrasonography
• Radionuclide scanning
• Biochemical markers

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CT

• Routine.
• More detail, invasion into adjacent structure
  pleural or lung parenchymal metastases.
• Sensitive method of distinguishing between fatty,
  vascular, cystic, soft tissue mass.
• Differentiation in solid and cystic mass 100.
• Solid mass-- homogeneity or inhomogeneity.
• Contrast enhancement of vessel.
• Cannot differentiate between benign and malignant
  tumor.

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MRI

• Additional useful information in separation
  mediastinal tumor from vessels and bronchi.
• Superior to CT in evaluation intraspinal
  extention or intrathecal spread of paravertebral
  mass.

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Ultrasonography

• -- Differentiation in solid and cystic.

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Radionuclide scanning

• Thyroid I131, I123.
• Parathyroid Tc 99m.
• Octreotide Somatostatin analogue, identifiy
  small cell carcinoid tumors of lung.
• Tc-99mpertechnate scan identified gastric
  mucosa in suspected neuroenteric cyst in
  posterior portion of visceral compartment.
• Gallium 67 differentiate benign from malignant
  anterior mediastinal mass.

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Biochemical markers

• a-fetoprotein, ß-human chorionic gonadotropin(ß
  HCG), ether one or both elevated in
  nonseminomatous malignant germ cell tumor.
• Excess than 500 ng/ml, can start chemotherapy
  without a tissue biopsy.
• 7-10 pure seminoma may elevated ß- HCG but nor
  exceed 100 ng/ml, but elevated a-fetoprotein is
  never present.

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Biochemical markers

• All infant and children with paravertebral mass
  should evaluated for excessive norepinephrine and
  epinephrine production.
• Ferritin level for neuroblastoma.
• Antiacetylcholine receptor antibodies thymoma.
• Positron emission tomographic scanning
  Differentiating a noninvasive thymoma.

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Invasive biopsy procedure

• Choice of invasive diagnostic procedures depends
  on
• Presence or absence of local symptoms.
• Location and extent of lesion.
• Presence or absence various tumor marker.

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Invasive biopsy procedure

• Do not require tissue biopsy before removal
• Asymptomatic lesion without systemic
• syndrome.
• Confined in anterior compartment.
• No elevating tumor marker.
• Biopsy of clinical stage I thymoma is to be
  avoid.

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Percutaneous transthoracic fine-needle aspiration

• CT or sono-guide.
• Anterior compartment lesionpositive result
  nearly 100.
• Complication is life-threating hemorrhage form
  injury internal mammary artery during parasternal
  needle biopsy.
• CT-guide is much better.
• Coaxial length-matched bone biopsy system guide
  by CT.

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Percutaneous transthoracic fine-needle aspiration

• Visceral compartmenttransthoracically with
  passage of needle through lung.
• Success rate 75.
• Complication pneumothorax is low.
• Paravertebral massCT-guide biopsy 100 success
  rate.

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Mediastinoscopy

• Anterior mediastinal tumor, the mediastinoscopy
  is NOT appropriate for biopsy May be obtain by
  cervical substernal extended mediastinotomy or
  anterior mediastinotomy.
• Lymph node confined to visceral compartment,
  biopsy via a standard cervical mediastinoscopy is
  used.