대한흉부영상의학회 Korean Society of Thoracic Radiology

Discussion

Diagnosis With Brief Discussion

Diagnosis

Thymic neuroendocrine tumor (carcinoid)

Radiologic Findings

Fig 1. Chest PA shows mass like consolidation in right lower lung zone with right pleural effusion.
Fig 2-4. CT scans reveals an anterior mediastinal mass with invasion to right side of pericardium and heterogeneous enhancement (average HU 80). Pleural effusion without definite enhancement is seen in right hemithorax with passive atelectasis of right lower lobe.
Fig 5. This lesion is measured about 7.7 X 5.6 cm in diameter on coronal image.
Fig 6. Thymectomy was done after embolization of feeding arteries. Hypervascular tumor stain appears on selective angiography of right internal mammary.

Brief Review

Atypical carcinoid tumor is an extremely rare (0.18 per 1,000,000 population) and characterized by a high degree of malignancy and invasiveness without specific clinical features. The clinical manifestation includes no obvious early symptoms(1/3), nonspecific symptoms such as cough, chest pain, breathing difficulties, and other symptoms related to the anterior mediastinal space-occupying lesions, or carcinoid syndrome related to the tumor producing ectopic hormones, such as serotonin(2% of patients) or adrenocorticotropic hormone(25% of patients). This tumor exhibits local recurrence or distant metastasis.
On CT images, a large mass with an irregular or lobulated shape in the mediastinum close to blood vessels or surrounding pericardium and immature blood vessels, and liquefied necrotic area within the tumor may suggest atypical carcinoid tumor. Due to lack of specificity of radiologic finding, histological evaluation is needed for final confirmation. The differential diagnosis of the atypical carcinoid tumor includes all kinds of primary mediastinal tumors, principally lymphoma, germ cell tumors, parathyroid adenoma or carcinoma, pericardial cysts, and metastatic tumors with other origins.
Recommended treatment of resectable atypical carcinoid tumor is completely surgical resection. And for unresectable case, chemotherapy with or without radiation therapy is recommended.

References

1. Zhu S, Wang Z-T, Liu W-Z, Zong S-X, Li B-S. Invasive atypical thymic carcinoid: three case reports and literature review. OncoTargets and therapy. 2016 Oct; 6171-6176.
2. K. Öberg, P. Hellman, P. Ferolla, M. Papotti. Neuroendocrine bronchial and thymic tumors: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up. Annals of oncology, 2012 Oct; 7120-7123
3. Hong-Bing Wang, Yu Yang, Xing-Wen Fan, Yin Xu, Jiang Long, Kai-Liang Wu. Thymic neuroendocrine tumors: an analysis of 18 cases and a literature review. Translation cancer research, 2016 Dec;5(6)

Keywords

anterior mediastinum, Neoplasm_Malignant,