May Be Caused by

 Common

Abscess

Goiter

Hemangioma

Infectious lymphadenopathy

Jugular thrombophlebitis

Lipoma

Lymphoma

Metastatic lymphadenopathy

Thyroglossal duct cyst

Thyroid adenoma

Thyroid carcinoma

 Uncommon

Colloid cyst of thyroid gland

Glomus caroticum

Hygroma

Laryngocele

Lymphocele

Neuroblastoma

Plexiform neurofibroma

Schwannoma

Second branchial cleft cyst

Teratoma

Thymic cyst

Tracheoesophageal cyst