Cervical thymic cyst.

Thymic derivatives should be included in the differential diagnosis of cystic masses in the neck. A classification of thymic cysts is proposed: namely, true mixed or false. A thymic cyst may contain cholesterol crystals in the luminal fluid, cholesterol clefts, granulomas and lymphocytic follicles as well as Hassall corpuscles in the wall. Treatment consists of simple excision of the cyst and its tract. The thirty-fifth case of cervical thymic cyst in the English Literature is reported.