An eruption cyst, or eruption hematoma, is a bluish swelling that occurs on the soft tissue over an erupting tooth. It is usually found in children. The fluid in the cyst is sometimes clear creating a pale-coloured cyst although often they are blue. An eruption cyst (eruption hematoma) is a developmental soft-tissue cyst of odontogenic origin that forms over an erupting tooth. most commonly seen anterior to first molar

• common in children while rare in other ages and found in both dentition
• forms superficially in the gingiva overlying the involved erupting tooth as soft, rounded and bluish swelling.

• The epithelial lining of eruption cyst is similar to that of the dentigerous cyst (non-keratinized stratified squamous epithelium), so the eruption cyst is considered a superficial dentigerous cyst.
• The fibrous capsule shows inflammatory cells possibly as a result of trauma.
• The epithelial lining of the cyst is separated from the alveolar mucosa by a thin layer of fibrous tissue with the epithelial tags of cystic epithelium facing those of the alveolar mucosa.
• The cystic cavity may contain blood in addition to the yellowish protein fluid as a result of trauma.

• The cyst roof may be drained with its fluid to allow the tooth to erupt although most of them burst spontaneously.^[1]