Case of the week Details

A - AP-Chest XRAY

• ARROW: Tracheal deviation to the Right.
• STAR: Opacified right hemithorax.
• Findings are consistent with Collapse of the right lung.

B – Axial CT thorax (soft tissue and lung window images)

• ARROW: Soft tissue density endobronchial mass lesion in the right main bronchus.
• STAR: Collapsed right lung and hypodense  fluid in the right hemithorax.

C – CORONAL CT THORAX

Ovoid heterogeneously isodense mass lesion with multiple tiny peripheral specks of calcifications in the right hemithorax with endobronchial extension.

D – Axial CT Thorax

• ARROW:  Isodense mass lesion with peripheral calcific specks and endobronchial extension.
• STAR: Organised / Clotted - Hemorrhagic contents in the right hemithorax.

FINDINGS AND IMPRESSION

• Ill-defined soft tissue density mass with few peripheral calcific specks in the right hemithorax extending into the right main bronchus with resultant bronchus cut off.
• Associated near complete collapse of the right lung with ipsilateral tracheo mediastinal shift.
• Irregular soft tissue density foci scattered within the right thoracic cavity with mild to moderate fluid – suggestive of haemothorax with organized haemorrhagic products.
• Mediastinal lymphadenopathy.

IMPRESSION: Centrally obstructing right hemithroacic endobronchial mass – likely neoplastic in etiology.

• DDX:
  • Endobronchial malignancy  like Bronchial carcinoid and Primary lung carcinoma—rare but possible at this age.
  • Less likely: Inflammatory endobronchial lesion or Endobronchial metastasis

Diagnosis

• Bronchoscopy –Right main bronchus completely occluded by mass.
• Biopsy – HPE: ATYPICAL CARCINOIDE TUMOR.

DISCUSSION - Endobronchial Carcinoid Tumor

• Neuroendocrine tumors arising from Kulchitsky cells of the bronchial mucosa
• Represent the most common primary endobronchial neoplasm in young adults
• Typically slow-growing but may cause significant airway obstruction

Histopathology

• Composed of uniform neuroendocrine cells arranged in nests, trabeculae, or rosettes.
• Classified as:
  • Typical carcinoid: <2 mitoses/2 mm², no necrosis
  • Atypical carcinoid: 2–10 mitoses/2 mm² and/or necrosis

Incidence and Epidemiology

• Account for 1–2% of all primary lung tumors.
• Incidence: ~0.2–2 cases per 100,000 population/year. Younger age group compared to other lung malignancies - Peak incidence: 30–50 years
• Slight female predominance. No strong association with smoking, especially for typical carcinoids.

Clinical Presentation

• Symptoms largely due to bronchial obstruction
• Dyspnea
• Recurrent pneumonia
• Hemoptysis (common due to tumor vascularity)
• Carcinoid syndrome is rare (<5%) in pulmonary carcinoids
• Delayed diagnosis common due to nonspecific symptoms

Radiological Findings

CHEST RADIOGRAPH

• Lobar or whole lung collapse
• Recurrent or non-resolving consolidation
• Opacified hemithorax with ipsilateral mediastinal shift in severe obstruction.

CT THORAX

• Well-defined central endobronchial mass
• Typically isodense to muscle
• Intense enhancement post-contrast (hypervascular)
• Secondary findings:
  • Atelectasis
  • Post-obstructive pneumonia
  • Mucoid impaction
  • Pleural effusion or hemorrhage (occasionally)

Other Diagnostic Imaging

• Contrast-enhanced CT: modality of choice for initial evaluation
• Somatostatin receptor imaging:
  • ^68Ga-DOTATATE PET/CT shows high sensitivity
• Bronchoscopy:
  • Direct visualization: smooth, cherry-red, highly vascular mass
  • Biopsy with caution due to bleeding risk

Prognosis and Management

• Surgical resection is the treatment of choice
• Excellent prognosis:
  • 5-year survival:
    • Typical carcinoid: >90%
    • Atypical carcinoid: 60–75%
• Early radiologic diagnosis prevents irreversible lung damage

Imaging Diagnostic Pearls

• Central enhancing endobronchial mass in a young, non-smoker → think carcinoid
• Persistent lobar collapse or recurrent pneumonia in the same distribution is a red flag
• Marked enhancement helps distinguish carcinoid from mucus plug or foreign body
• Lack of nodal disease favors typical carcinoid
• Always evaluate for endobronchial extension on CT lung windows

References

1. Travis WD, Brambilla E, Nicholson AG, et al. The 2015 World Health Organization classification of lung tumors. J Thorac Oncol. 2015;10(9):1243–1260.
2. Caplin ME, Baudin E, Ferolla P, et al. Pulmonary neuroendocrine (carcinoid) tumors: ESMO Clinical Practice Guidelines. Ann Oncol. 2015;26 Suppl 5:v102–v108.
3. Erasmus JJ, McAdams HP, Patz EF Jr, Goodman PC. Bronchial carcinoid tumors: radiologic findings in 22 patients. Radiology. 1998;206(2):497–502.
4. Chong S, Lee KS, Chung MJ, et al. Neuroendocrine tumors of the lung: clinical, pathologic, and imaging findings. Radiographics. 2006;26(1):41–57.
5. Kayser K, Zink S, André S, et al. Typical and atypical carcinoid tumors of the lung: differentiation by morphometry and immunohistochemistry. Pathol Res Pract. 2001;197(10):697–703.

DR. K VISHNU VARDHAN REDDY
MBBS, MD, Fellowship In Cross Section Imaging (MHRG).