Date post: | 03-Jun-2015 |
Category: |
Science |
Upload: | fern-ferretie |
View: | 237 times |
Download: | 1 times |
Atypical pulmonary metastasis
Chest Conference
THORSANG CHAYOVAN
26.08.2014
Principle of pulmonary metastasis
• Lung is a filter-like organ – The venous return contains lymphatic fluid from the
body tissues flows into the lung
• Pulmonary metastasis is extremely common
• Incidence of metastases to lung parenchyma – 20% to 54% of patients who died of malignancy
• The common primary organs are: – Breast, colon, kidney, uterus, H&N
– Choriocarcinoma, osteosarcoma, testis, melanoma, Ewing’s sarcoma, thyroid carcinoma
Pathogenesis of pulmonary metastasis
• 5 mechanisms 1. Pulmonary or bronchial artery
2. Lymphatics
3. pleural space
4. Airway 5. Direct neoplastic invasion
• Hematogenous spread--most common – Most reach the arterioles and capillary beds
– Some survive and grow into the interstitium
Typical pulmonary metastasis
• Hematogenous
-> Random distribution
-> Multiple
-> Round-shaped
-> Variable-sized
• Diffuse thickening of the interstitium (lymphangitic carcinomatosis)
Atypical pulmonary metastasis
• Unusual radiologic features of metastases – Poorly-defined/irregulary-marginate nodules – Cavitation – Calcification – Hemorrhage around the metastatic nodules – Pneumothorax – Air-space pattern – Tumor embolism – Endobronchial metastasis – Solitary mass – Dilated vessels within a mass – Sterilized metastasis
Nodule
• The most common presentation of metastasis
• Spherical nodules of varying size
• Random or peripheral
• Basal portion of the lung
• Tumor cells hematogenously transferred to the lung proliferate into the perivascular interstitium
– > interstitial lesions: clear, smooth margins
• Tumors grow out of vessels into the interstitium and alveolar air space
– > lung parenchymal lesions
Nodule
• At autopsy,
– 38% well-defined, smooth margins
– 16% well-defined, irregular margins
– 16% poorly-defined, smooth margins
– 30% poorly defined, irregular margins
Comparison of HRCT to histopathological characteristics
• Well-defined, smooth margins
– Expanding type
– Alveolar space-filling type
• Poorly-defined margins
– Alveolar cell type
• Irregular margins
– Interstitial proliferating type
Correlation between the histological type of the primary tumor and the CT
appearance • Well-defined smooth margin
– Expanding type – Observed in most metastatic HCC
• Metastatic adenocarcinomas – Poorly defined, either irregular or smooth margins – alveolar cell type and interstitial proliferation type
• Irregular margins – Metastatic squamous cell carcinomas
• Irregular margins – Metastases after chemotherapy
Well-defined, smooth margin
HCC
Expanding type
Adenocarcinoma Poorly-defined, irregular margin
Alveolar cell type
Cavitation
• Incidence – 4% in metastases – 9% in primary lung cancer
• 70% are metastatic squamous cell carcinomas • The most common primary organ
– Head and neck in males – Genitalia in females
• Metastatic adenocarcinoma – no statistically significant difference in the frequency of
cavitation between the two histologic types.
• Metastatic sarcoma – Pneumothorax is a frequent complication
• Chemotherapy is known to induce cavitation • Indeterminate mechanism
Aquamous cell CA
Adenocarcinoma of rectum
Angiosarcoma of scalp with pneumothorax and hemorrhage
Squamous cell CA S/P chemotherapy
Calcification
• Benign nodules
– Granuloma
– Hamartoma: less common
• Calcification in metastasis
Calcification in metastasis
• Morphology-specific
1. Dense eccentric—osteosarcoma
2. Multifocal—osteosarcoma, chondrosarcoma
3. Dystrophic—after treatment
• Morphology-nonspecific
– Synovial sarcoma, giant cell tumor, colon, ovary, breast, thyroid, choriocarcinoma
Osteosarcoma
Hemorrhage around metastatic nodules
• CT halo sign – nodular attenuation surrounded by a halo of ground-
glass opacity
• Ill-defined fuzzy margins
NON-SPECIFIC!!
• Invasive aspergillosis • Candidiasis • Wegener granulomatosis • Tuberculoma • Bronchioloalveolar carcinoma • Lymphoma
Hemorrhagic metastatic nodules
• Examples
– Angiosarcoma
– Choriocarcinoma
Choriocarcinoma with hemorrhagic metastasis Multiple nodular attenuation with surrounding GGO
Pneumothorax
• A result of tumor necrosis
• In aggressive and necrotic tumors – Osteosarcoma: most frequent—5-7% of cases
– Other sarcomas
• Necrosis of subpleural metastases produces a bronchopleural fistula -> Pneumothorax
• 10 of 1,143 cases with a spontaneous pneumothorax have been attributed to a malignancy
• A spontaneous pneumothorax in a patient with a sarcoma should raise the possibility of occult pulmonary
Osteosarcoma with pneumothorax
Air-space pattern
• Metastases from an adenocarcinoma, breast and ovary origin – May spread into the lung along the intact alveolar
walls (lepidic growth)
– Also in BAC
• The radiologic features mimic pneumonia – Air-space nodules
– Consolidation containing an air bronchogram
– Focal or extensive ground-glass opacities
– CT halo signs
Adenocarcinoma of stomach
Tumor embolism
• In small or medium arteries
• Diagnosis is difficult radiologically – Multifocal dilatation and beading of the peripheral
subsegmental arteries
– Infarction: peripheral wedge-shaped areas of attenuation
– Large tumor emboli in the main, lobar, or segmental pulmonary arteries
• Tumors frequently associated with pulmonary tumor emboli – Hepatomas, breast and renal cell carcinomas, gastric and
prostatic cancers, and choriocarcinomas
HCC with massive tumor emboli
Endobronchial metastasis
• Rare • Major airway in only 2% of cases • Two possible routes 1. Directly on the bronchial wall
– Aspiration of tumor cells – Lymphatic spread – Hematogenous metastasis to the bronchial wall -> polypoid lesion inside the bronchial lumen
2. Tumor cells in the lymph nodes or lung parenchyma that surround the bronchus grow along the bronchial tree -> intraluminal lesion
• Kidney, breast, and colorectal cancers
• The most common radiologic appearance
– Lobar atelectasis
RCC
Endobronchial metastasis
RCC with endobronchial
metastasis
• Solitary metastasis without a history of malignancy
– CT: 0.4%–9.0%
– Chest radiograph: 25%
• Solitary pulmonary nodules detected in patients with extrapulmonary malignancies
– 46% proved to be a metastasis
Solitary metastasis
• The likelihood that a solitary nodule represents a pulmonary metastasis
– varies according to the histologic type of the primary tumor and the patient’s age
• The most frequent malignancies
– melanoma; sarcoma; and cancer of the colon, breast, kidney, bladder, and testis
Solitary metastasis
Dilated vessels within mass
• Engorged tumor vessels
– Suggest hypervascularity
– Sarcoma
• Alveolar soft-part sarcoma
• Leiomyosarcoma
Dilated vessels in alveolar soft-part sarcoma metastasis
Sterilized metastasis
• After adequate chemotherapy
• Necrotic nodules with or without fibrosis and without viable tumor cells
• Histologic confirmation is necessary
• Common: choriocarcinoma and testis
• Germ cell tumors can convert to a benign mature teratoma after chemotherapy and result in persistence of the masses
Benign Metastasizing Tumor
• Rare • Generally originate from
– Leiomyoma of the uterus – Hydatidiform mole of the uterus – Giant cell tumor – Chondroblastoma – Pleomorphic adenoma of the salivary gland – Meningioma
• Despite their metastatic spread, these tumors are histologically benign.
• Indistinguishable from malignant tumors, however, benign ones show very slow growth
Benign metastasis from a uterine leiomyoma
Conslusion
• Radiological diagnoses--based on typical findings
• Awareness of the spectrum of radiologic manifestations in atypical pulmonary metastases
• Presence of atypical radiologic features and metastasis is suspected
– > tissue diagnosis is recommended
Typical pulmonary metastasis
• Random distribution
• Lower distribution
• Multiple
• Round shape
• Variable size
Atypical pulmonary metastasis
• Poorly-defined/irregulary-marginate nodules
• Cavitation
• Calcification
• Hemorrhage
Atypical pulmonary metastasis
• Pneumothorax
• Air-space pattern
• Tumor embolism
• Endobronchial metastasis
• Solitary mass
• Dilated vessels within a mass
• Sterilized metastasis
THANK YOU
• "Atypical Pulmonary Metastases: Spectrum of Radiologic Findings."RadioGraphics:. N.p., n.d. Web. 24 Aug. 2014.
• "Atypical Pulmonary Metastases: Spectrum of Radiologic Findings."RadioGraphics:. N.p., n.d. Web. 24 Aug. 2014
References