female presents with repeated attacks of respiratory tract infection. CT
scan of the chest is performed.
What is the diagnosis?
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Bronchial carcinoid tumors are rare, accounting for as many as 2.5% of all pulmonary neoplasms and for 12-15% of carcinoid tumors overall. They originate from the neurosecretory cells of bronchial mucosa and were previously classified as bronchial adenomas, a term no longer used. Bronchial carcinoids are now classed as low-grade malignant neoplasms because of their potential to cause local invasion, their tendency for local recurrence, and their occasional metastases to extrathoracic sites. Bronchial carcinoid tumors arise from Kulchitsky cells (argentaffin cells) within the bronchial mucosa. The predominant distribution of cells occurs at the bifurcation of the lobar bronchi.
Histologically, bronchial carcinoids can be categorized into two groups:
Kulchitsky cell carcinoma (KCC) I (typical carcinoids), KCC II, (atypical
Most tumors follow a benign course and are amenable to surgery. The 5-year survival rate for patients with typical bronchial carcinoid (KCC I) is 94%.
CT provides excellent anatomic detail of both the endobronchial and the
extraluminal components of the tumor. Tumors usually deform or obstruct
the adjacent bronchus, and even peripheral tumors are shown to lie in
immediate proximity to a recognizable small airway. As on CXRs, lesions
usually appear as well-defined, lobulated, round or oval masses sized
2-4 cm. Extension into adjacent mediastinal structures is detectable on
CT scans in more aggressive tumors.