Carcinoid : Spindle Cell
A subset of pulmonary carcinoids is located peripherally (sub-pleurally) and such cases are usually composed of spindle cells. They may be mistaken for leiomyoma. Immunoreactivity for neuroendocrine markers is helpful in distinguishing them from other mesenchymal neoplasms. Given their peripheral location, they are often symptomatic and discovered incidentally. When large or multiple, they may produce pulmonary symptoms due to reduced pulmonary capacity.