대한흉부영상의학회 Korean Society of Thoracic Radiology

Discussion

Diagnosis With Brief Discussion

Diagnosis

Typical carcinoid

Radiologic Findings

Pre-enhanced CT scan shows a well-defined lobulated contoured soft tissue mass without calcification in left lower lobe. Post-enhanced CT scan reveals heterogenous well-enhancing mass within the left lower lobe bronchus. PET scan reveals irregular moderate hypermetabolic activity in posterior aspect of left lower lobe (SUVp:3.4), which is in the atelectatic lung not in the mass. The patient had right mastectomy and presented with recent history of intermittent blood tinged sputum. Differential diagnosis included endobronchial metastasis, lung cancer and other endobronchial tumor, such as carcinoid. Carcinoid tumor was confirmed by PCNB. Previous chest CT scan was reviewed and the patient has the tumor since three years without interval change.

Brief Review

Carcinoid tumor is a low-grade malignant tumor, only aout 0.5% to 2.5% of all pulmonary neoplasm. Typical carcinoid represents 80% to 90% of carcinoid tumors. Typical carcinoids tend to be more central and to be smaller at presentation. Sixteen to 40 % are peripheral; the others are central. Centrally located bronchial carcinoids may e predominantly intraluminal. Assuming a polypoid configuration, may grow along the lumen of the bronchus, or may be predominantly extraluminal, in which case they are known as ‘iceberg’ lesions.

CT scan usually shows the anatomic relationship of the central mass with the bronchus. Small tumors in segmental and subsegmental bronchi may result in mucous distension of the bronchi beyond the obstruction. Because bronchial carcinoid tumors are very vascular, marked enhancement may be seen following IV administration of contrast medium. On FDG PET, pulmonary carcinoid tumors usually have lower FDG uptake than expected for malignant tumors.

References

1. Foster BB, Muller NL, Miller PR, Nelems B, Evans KG. Neuroendocrine carcinoma of the lung: clinical, radiologic, and pathologic correlation. Radiology 1989;170:441-445.

2. Erasmus JJ, McAdams HP, Patz EF Jr, Coleman RE, Ahuja V, Goodman PC. Evaluation of primary pulmonary carcinoid tumors using FDG PET. AJR 1998;170:1369-73.

3. Fraser RS, Muller NL, Colman N, Pare PD. Diagnosis of diseases of the chest. 4th ed. Saunders: Philadelphia, 1999;1229-1243.

Keywords

Airway, Malignant tumor,