Peripheral pulmonary carcinoid tumour

Peripheral pulmonary carcinoid tumour refer to a subtype of pulmonary carcinoid tumours that arise within the periphery of the lung. They are considered less common than the more centrally-located bronchial carcinoid tumours. 

Clinical presentation

Many patients tend to be asymptomatic  ². Presentation with carcinoid syndrome is extremely rare ⁶. 

Pathology

Peripheral pulmonary carcinoid tumours are considered a neuroendocrine tumour of the lung. They can be typical (well-differentiated - common) or atypical (more aggressive - uncommon). 

Risk factors

• smoking: rate of carcinoid tumours is similar between smokers and non-smokers, although there is increased incidence of atypical subtype amongst smokers ^5,6

Radiographic features

HRCT/CT chest

Most are discovered as an incidental rounded solitary pulmonary nodule. The size at diagnosis can vary but is usually reported to be in the range of 10-30 mm ². Many have a lobulated margin with an average Hounsfield value on postcontrast imaging of ~50 ². Imaging features are often non-specific and tissue diagnosis is essential in determining diagnosis.

Most peripheral carcinoid tumours tend to involve a subsegmental bronchus ². 

Nuclear medicine

FDG-PET

May have a sensitivity of around 75% ⁷.

Galliun68-Octeotide-PET / ⁶⁸Ga-DOTATATE 

Usually avid and useful for diagnosis ⁸.

See also

• carcinoid tumours
• solitary pulmonary nodule
• pulmonary tumourlets