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residual cyst
Tuesday 10 May 2016
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Definition: Inflammatory fibrous and granulation tissue at the apex/periapical region of a tooth not removed/curetted at the time of dental extraction may give rise to residual cyst. They represent 8% of all jaw cysts.
Synopsis
Radiograph demonstrates radiolucent lesion in toothbearing region of jaws without a close association to the periapical region of tooth.
Histology shows benign hyperplastic squamous epithelium.
May or may not show spongiosis or acanthosis.
Acute or chronic inflammation may be present.
Differential diagnosis
unicystic ameloblastoma , inflamed
odontogenic keratocyst , inflamed
glandular odontogenic keratocyst , inflamed
lateral periodontal cyst , inflamed
maxillary surgical ciliated cyst , inflamed
Prognosis
Vast majority have excellent prognosis. True residual cysts do not recur after appropriate treatment and are not premalignant. They have no increased risk of squamous cell carcinoma.
Associations
Occasionally, a secondary pathology, such as squamous cell carcinoma, may arise from the epithelial lining of radicular cysts, or other odontogenic gnathic cysts. Careful patient questioning and clinical examination are necessary to exclude a primary oral mucosal neoplasm or metastases.
It is also needed to rule out an epithelial neoplasm which underwent secondary cystic change.
Histological evidence of cyst lining with transition to epithelial dysplasia and infiltrating squamous carcinoma provides acceptable proof.