Atypical Carcinoid of Thymus : Definition
Atypical carcinoid, by definition, shows increased mitotic activity (2-10 mitotic figures/HPF) and/or foci of necrosis. Atypical carcinoids are seen far more commonly than typical carcinoids in thymus. As a group, thymic carcinoid is a more aggressive tumor than bronchial carcinoid. The usual age at presentation is around 50 years with a male predominance. This image shows necrosis, coarse calcifications and increased mitotic activity in an atypical carcinoid of thymus.