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 nonsmokers, 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 usually reported to be range around 10-30mm ². Many have lobulated margin with an average Hounsfield value on post contrast imaging at around 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