Diagnostic Workup and Treatment of Tracheal Mass with Castleman Disease Features
Initial Diagnostic Approach
For a tracheal mass resembling lymph nodes with Castleman disease features, tissue diagnosis via biopsy is mandatory, with the specific approach determined by the mass location and accessibility. 1
Biopsy Strategy
Bronchoscopy with transbronchial needle aspiration (TBNA) or endobronchial ultrasound-guided needle aspiration (EBUS-NA) is the preferred initial approach for accessible tracheal masses, with EBUS-NA demonstrating a diagnostic yield of 93% and specificity of 100% for mediastinal and airway lesions 1
Use 19-gauge needles to obtain adequate tissue for both histologic evaluation and immunophenotyping, as larger needles provide better tissue samples essential for definitive diagnosis 1
Rapid on-site cytopathologic evaluation should be performed during the procedure to ensure specimen adequacy and reduce the need for repeat procedures 1
If TBNA/EBUS-NA is non-diagnostic or yields insufficient tissue, proceed directly to surgical excisional biopsy rather than repeating needle techniques, as Castleman disease requires adequate tissue architecture for diagnosis 1, 2
Essential Pathologic Evaluation
The pathology specimen must include immunohistochemistry for CD20, CD30, CD15, and HHV-8 to differentiate Castleman disease from lymphoma and determine disease subtype 3, 4
Request evaluation for characteristic "onion skin" and "lollipop" appearances that are pathognomonic for hyaline-vascular type Castleman disease 4
Ensure testing for HHV-8 is performed, as HHV-8-negative status supports unicentric Castleman disease rather than multicentric disease 4
Comprehensive Staging Workup
Imaging Studies
Obtain contrast-enhanced CT of chest, abdomen, and pelvis to identify additional lymphadenopathy and distinguish unicentric from multicentric disease 1, 4
PET/CT from skull base to mid-thigh is recommended to detect occult disease sites and assess metabolic activity, though Castleman disease may show variable FDG uptake 3, 5
Chest MRI with and without contrast may be obtained if CT findings are equivocal or to better characterize the relationship of the mass to adjacent vascular structures 1
Laboratory Evaluation
Complete blood count, comprehensive metabolic panel including LDH, and inflammatory markers (CRP, ESR) should be obtained 1
HIV testing and hepatitis B/C screening are mandatory, as multicentric Castleman disease is associated with HIV and HHV-8 infection 1, 4
Serum IL-6 levels should be measured if systemic symptoms are present, as elevated IL-6 suggests multicentric disease 1
Exclusion of Alternative Diagnoses
Rule out lymphoma (particularly Hodgkin lymphoma and large B-cell lymphoma) through immunophenotyping, as mediastinal/tracheal lymphadenopathy with CD20 positivity can represent either entity 1, 3
Exclude thymic tumors if the mass is in the anterior mediastinum/upper trachea by assessing for typical thymic tumor markers and location 1
Consider infectious etiologies (tuberculosis, fungal infections) in the differential, particularly if the patient has risk factors or atypical presentation 1
Treatment Algorithm
Unicentric Castleman Disease (Localized Tracheal Mass)
Complete surgical excision is the definitive treatment of choice for unicentric Castleman disease, offering excellent outcomes with potential cure 4, 6, 7, 2
For endotracheal lesions causing airway obstruction, laser resection or rigid bronchoscopy with tumor debulking may be required as initial management to secure the airway before definitive surgical resection 2
Video-assisted thoracoscopic surgery (VATS) or open surgical approach should be selected based on mass size, location, and relationship to critical structures 5
No adjuvant therapy is required after complete resection of unicentric disease, as surgical excision alone is curative 4, 7
Multicentric Castleman Disease (If Multiple Sites Identified)
Systemic chemotherapy is required for multicentric disease, though specific regimens are beyond the scope of isolated tracheal masses 4
Rituximab-based therapy is the standard approach for HHV-8-associated multicentric Castleman disease 4
Critical Pitfalls to Avoid
Do not rely on fine needle aspiration alone for diagnosis, as the architectural features essential for diagnosing Castleman disease require core biopsy or excisional biopsy 1
Do not assume benign disease based on imaging characteristics alone, as intrapulmonary and tracheal Castleman disease can mimic malignancy on CT and PET imaging 6, 5, 7
Do not proceed with definitive surgery without tissue diagnosis unless the mass is causing critical airway compromise requiring emergent intervention 2
Ensure adequate long-term follow-up after resection, as there is a small risk of malignant transformation to lymphoma, though this is rare with unicentric disease 4