Radiologic Findings of Lymphangitic Carcinomatosis on HRCT
The characteristic radiologic findings of lymphangitic carcinomatosis on high-resolution computed tomography (HRCT) include thickening of interlobular septa, fissures, and bronchovascular bundles, which may have a focal or diffuse, unilateral or bilateral, and symmetric or asymmetric distribution. 1
Key HRCT Features
- Thickening of interlobular septa, which appears as uneven or irregular linear opacities 1
- Thickening of bronchovascular bundles, creating a nodular appearance along the bronchovascular structures 1
- Presence of polygonal lines, representing thickened interlobular septa forming geometric patterns 1
- Thickening of fissures due to tumor infiltration of lymphatics 1
- Preservation of normal lung architecture despite interstitial infiltration 2
Distribution Patterns
- Distribution can be focal or diffuse throughout the lungs 2
- May present as unilateral or bilateral involvement 2
- Can be symmetric or asymmetric in appearance 2
- May show lobar or segmental predominance in some cases 2
Additional Imaging Findings
- Ground-glass opacities may be present due to associated edema or partial filling of air spaces 1
- Pleural effusions may coexist with lymphangitic spread 3
- Normal chest radiographs may be seen in early disease, with HRCT being more sensitive for detection 1, 4
- Nodular thickening of the peribronchovascular interstitium can create a "beaded chain" appearance 1
Pathologic Correlation
- The radiologic findings correlate with tumor thrombi in lymphatic vessels rather than edema and fibrosis, especially in early disease 1
- The thickening of interlobular septa and bronchovascular bundles corresponds to tumor cells infiltrating these structures 1
Diagnostic Considerations
- HRCT is the imaging modality of choice for diagnosing lymphangitic carcinomatosis 2
- FDG-PET may show diffuse, lobar, or segmental uptake in extensive disease, or linear/hazy areas of uptake in limited disease 2
- Transbronchial biopsy may be necessary for definitive diagnosis, especially when differentiating from other interstitial lung diseases 5, 6
Clinical Implications
- Lymphangitic carcinomatosis is most commonly seen with adenocarcinomas of various origins including breast, lung, stomach, and colon 2, 5, 6
- The presence of lymphangitic carcinomatosis generally indicates advanced disease with poor prognosis 2
- Early detection through HRCT can help guide appropriate management, even when chest radiographs appear normal or nonspecific 1
Common Pitfalls
- Lymphangitic carcinomatosis may mimic other interstitial lung diseases such as sarcoidosis, leading to misdiagnosis 5
- The clinical presentation can be nonspecific with progressive dyspnea, potentially delaying diagnosis 6
- In patients with no known primary malignancy, lymphangitic carcinomatosis may be the first manifestation of occult cancer 4, 5, 6