Botryoid Odontogenic Cyst

Botryoid odontogenic cyst is a rare developmental cyst that is a multilocular, grape like variant of the lateral periodontal cyst. It lies beside the root of a vital tooth and is lined by thin epithelium with focal plaques.

It occurs in adults in the fifth to seventh decades, most often in the mandibular canine and premolar region, and is usually discovered on a radiograph. It recurs more often than its unilocular counterpart.

Pathophysiology. The cyst is thought to arise from rests of the dental lamina in the periodontal ligament. The multilocular pattern results from the fusion of several small cystic spaces that grow together.

The lining is thin, non-keratinised epithelium with clear cell plaques, and the wall is fibrous with little inflammation.

Usually no symptoms. Some have painless swelling of the alveolar ridge or gingiva, bluish discolouration, slight mobility or displacement of neighbouring teeth, and occasionally mild tenderness. The adjacent teeth are vital.

Rapid growth, pain, numbness of the lip or cortical perforation suggests another diagnosis and needs prompt biopsy.

• Panoramic and periapical radiographs: a well defined, corticated, multilocular radiolucency (a cluster of small compartments with scalloped outlines) beside the roots, with root divergence in some.
• Cone beam CT for extent, loculation, relation to the inferior alveolar canal and mental foramen, and surgical planning.
• Pulp sensibility tests: the adjacent teeth respond normally, separating the lesion from a lateral radicular cyst.
• Biopsy and histology of the whole lesion: multiple thin walled cysts lined by one to a few layers of epithelium with glycogen rich clear cell plaques, in a fibrous wall.
• Aspiration to exclude vascular lesions, and keratin staining to exclude keratocyst.

Differential diagnosis.

• Lateral periodontal cyst (unilocular)
• Odontogenic keratocyst
• Glandular odontogenic cyst
• Unicystic or multicystic ameloblastoma
• Central giant cell granuloma
• Lateral radicular cyst
• Periodontal abscess and intrabony defect

• Enucleation with careful curettage and gentle peripheral osteotomy of the cavity, preserving the vitality of the adjacent teeth when possible. Send all tissue for histology.
• Large lesions or those close to the mandibular canal: decompression for 6 to 12 months, followed by enucleation of the residual cavity.
• Reported recurrence is about 30 to 40% with enucleation alone, and the figure is based on small series with lower certainty. Complete removal of each locule reduces the risk.
• Antibiotics only for infection with spread: amoxicillin 500 mg orally three times daily for 5 days (reduce to 500 mg every 12 hours at eGFR 10 to 30), or clindamycin 300 mg four times daily in penicillin allergy.
• Analgesia: paracetamol 1 g every 6 hours (maximum 4 g daily) with ibuprofen 400 mg every 8 hours with food for 2 to 3 days.

Monitoring. Radiographs at 6 and 12 months, then annually for at least 5 years. Recurrence is treated by re-excision with a wider margin.

Referral and escalation. Refer to oral and maxillofacial surgery for biopsy and surgery. Urgent referral for rapid growth, pain, lip numbness or histology that is not typical.