Man with back pain.

Our appreciation is extended to Dr.  Peter Miller, Indiana University Department of Radiology, for contributing this case.

Click these images to enlarge them.



Which choice is the most likely?

Old tuberculosis.Primary lung cancer.Primary pleural malignancy.Metastatic pulmonary disease.Neurogenic tumor.

Man with back pain.

Here are some CT images on the same patient. Click to enlarge.

Please respond to the following with TRUE or FALSE.

Man with back pain.

Smoker with back pain, scapula pain, feeling off balance.
Here are some PET CT and MRI images on the same patient, which further demonstrate extent of malignant involvement. Click to enlarge.

Findings:

CXR:  Large right apical mass with associated posterior third rib destruction and questionable involvement of posteromedial second rib.

Chest CT:  Large right upper lobe mass consistent with primary malignancy, possibly Pancoast tumor.  There is invasion into the neuroforamina in the upper thoracic spine at T1-T4 with extension into the spinal canal with mass effect upon cord.  There is bony destruction of the right third rib, transverse process of T3 and invasion into the chest wall and right paraspinal muscles.

MRI Thoracic spine and cervical spine:  Large right lung apical tumor with significant epidural extension, resulting in severe cord compression from the levels of upper T2 through mid T3 with evidence of cord edema.  The lesion is invading into the spinal canal through the right neuroforamina of C7-T1, T1-T2, T2-T3, and T3-T4, with expansion of the foramina at T1-T2 and T2-T3.  There is extensive epidural soft tissue starting with small amount of mass in the C7-T1 level, then large amount of tumor filling of the right lateral canal from T1-T2, resulting in significant compression of the cord from levels upper T2 through mid-T3.  The epidural mass extends inferior in the right side of the spinal canal to the level of T4-T5.  There is increased intramedullary T2 prolongation at T2 and T3, consistent with cord edema.  Extensive right lateral and posterior paravertebral muscles and soft tissue infiltration.

PET CT:  The right apical mass is peripherally hypermetabolic.  Hypermetabolic component seen from T1-T4.  Probable small additional hypermetabolic, hyperattenuating focus within the central canal at the level of the T5.

Man with back pain.

Discussion

• NSCLC (Non-small cell lung cancer) includes adenocarcinoma (35-40%), squamous cell carcinoma (25-30%), large cell carcinoma (10-15%).
• Similar staging and treatment options
• Smoking related in >85%
• 170,000 diagnosed annually in US and 150,000 deaths annually. Most common cause of cancer death in the U.S.
• 5 year survival rate 15%
• The International Association for the Study of Lung Cancer (IASLC) serves as the primary source of recommendations for lung cancer staging revisions recognized by the International Union Against Cancer (UICC)
• New 7th edition of the TNM staging system for lung cancer incorporates several proposed revisions to better align TNM staging with prognosis and treatment

Chart illustrates the descriptors from the 7th edition of the TNM staging system for lung cancer:

UyBico S J et al. Radiographics 2010;30:1163-1181

 

Stage Groupings in the 6th and 7th Editions of the TNM Staging System for Lung Cancer:

UyBico S J et al. Radiographics 2010;30:1163-1181

• Changes regarding tumor:
  • Stage T4 disease is downgraded to stage T3 when satellite nodules are present in the same lobe as the primary lesion
  • Stage M1 disease is downgraded to stage T4 when nodules are present in the same lung but not the same lobe as the primary lesion.
  • The presence of malignant pleural effusion, pleural dissemination, or pericardial disease is now considered metastatic disease—M1a for local intrathoracic disease—rather than stage T4 disease.
• Changes regarding Nodal spread of disease shown in table below
  • Lymphatic drainage of lung cancer: Tumors from the right upper lobe drain to the right paratracheal nodes. Tumors from the left upper lobe drain to the peri- and subaortic lymph nodes. Tumors from the middle and lower lobes drain to the subcarinal nodes. Direct drainage to the mediastinal lymph nodes without drainage to the hilar and interlobar nodes sometimes occurs ("skip metastasis").

 

UyBico S J et al. Radiographics 2010;30:1163-1181

 

• Changes regarding M category
  • M1a (intrathoracic spread) and M1b (disseminated disease involving extrathoracic spread).
  • Malignant pericardial and pleural diseases are now considered to be metastatic (M1a) disease, rather than stage T4 disease.
• Treatment:
  • Stage IA, IB, IIA, IIB, and sometimes IIIA disease are surgically resectable +/- neoadjuvant or adjuvant chemotherapy and radiation therapy.
  • Stage IIIB and IV chemo and radiation. Consider resection of adrenal or brain metastases.
  • Targeted therapy for advanced disease

Radiologic overview of the diagnosis:

• Radiography
  • Nodule or mass ranging in size from 1-10 cm
  • Central tumor with hilar or mediastinal enlargement
  • Rib destruction or presence of extrathoracic soft tissue mass is specific for chest wall invasion
• NECT
  • Evaluate primary tumor and mediastinal adenopathy
  • Cavitation more frequent in squamous cell histology
  • Peripheral adenocarcinomas may be solid, mixed solid and ground glass or pure ground glass density lymphangitic carcinomatosis
  • Pulmonary metastases in non-tumor lobe
  • Synchronous or metachronous primary neoplasm (<2%)
• CECT
  • Better at detecting small endobronchial lesions
  • Mediastinal lymph nodes > 1 cm short axis abnormal
  • Subcarinal lymph nodes: >1.2 cm short axis
  • CT findings suggesting chest wall invasion:
    • Obtuse angles at point of contact of tumor and pleura
    • Greater than 3cm of contact between tumor and pleura
    • Pleural thickening
    • Infiltration of extrapleural fat
    • Rib destruction
• MR findings
  • MR is equal to CT in ability to diagnose chest wall invasion.
  • T2 shows contrast between tumor and chest wall muscle and fat
  • Early obliteration of high-signal extrapleural fat
  • Great to see brachial plexus or subclavian artery involvement
• PET
  • Activity greater than mediastinal background SUV > 2.5
  • False positive: Infection, sarcoidosis
  • False negative: Lesions < 1 cm, low grade adenocarcinomas, bronchioloalveolar carcinoma, carcinoid tumor
  • Mediastinum: SUV > 2.5 or above background considered abnormal Specificity 80%
  • Positive result must be confirmed pathologically

Key points:

• NSCLC is most likely diagnosis in tobacco users with focal lesion on chest radiograph
• NSCLC is etiology for a non resolving pneumonia due to bronchial obstruction
• Tumors invading the chest wall, diaphragm, mediastinal pleura, pericardium, or proximal main stem bronchus are T3 and considered resectable
• Tumors of any size that demonstrate local invasion of the mediastinum or carina, trachea, heart, great vessels, esophagus, or vertebral bodies are still considered stage T4 tumors according to new TNM system and are not resectable. Treat with chemo and radiation therapy

References:

1. Brant WE, Helms CA. Fundamentals of diagnostic radiology, 3nd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2007:447-450.
2. UyBico et al. Lung Cancer Staging Essentials: The New TNM Staging System and Potential Imaging Pitfalls. Radiographics 2010; 30: 1163-1181.
3. Statdx. Lung Cancer, Non-small cell. Accessed 6/01/2011.

Man with back pain.

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