• Inverted Pear-shaped Radiolucency: Globulomaxillary cyst.

  • Associated teeth need not be non-vital.

  • Klestadts’s cyst: Soft tissue variant of Globulomaxillary cyst.

• Tear Drop-shaped Radiolucency: Lateral Periodontal Cyst.

  • Associated teeth are vital.

• Cluster of Similar Cysts / Cluster of Grapes: Botryoid Odontogenic Cyst.

• Most Common Benign Odontogenic Tumor: Odontoma (Ameloblastoma is second).

• Adenoid Cystic Carcinoma vs. Adenomatoid Odontogenic Tumor (AOT):

  • Adenoid Cystic Carcinoma: Salivary gland malignancy.

  • Adenomatoid Odontogenic Tumor (AOT): Benign odontogenic tumor. Do not confuse them.

• Liesegang Rings: Can be seen in CEOT/Pindborg's Tumor (primarily) and AOT (rarely).

• Amyloid-like Deposits: Characteristic feature of CEOT (Calcifying Epithelial Odontogenic Tumor).

• Duct-like Structures: Seen in AOT (Adenomatoid Odontogenic Tumor).

• Granular Cell Ameloblastoma: Granules are lysosomal aggregates.

• Epithelial Plaques (localized thickenings): Found in:

  • Lateral Periodontal Cyst

  • Botryoid Odontogenic Cyst

  • Gingival Cyst of Adults

  • Glandular Odontogenic Cyst

Shape Recognition (Classic Boards Question)

• Heart/Oval Shape → Nasopalatine cyst
• Inverted Pear/Teardrop → Globulomaxillary cyst
• No Radiographic Feature → Nasolabial cyst

Location-Based Diagnosis

• Midline Maxilla (anterior) → Nasopalatine cyst
• Between maxillary lateral incisor & canine → Globulomaxillary cyst
• Midline Mandible → Median mandibular cyst
• Nasolabial fold → Nasolabial cyst

Clinical Correlations

• Spacing between centrals → Nasopalatine cyst
• Root divergence → Globulomaxillary cyst
• Nasal obstruction → Nasolabial cyst
• Usually asymptomatic → Median mandibular cyst

DIFFERENTIAL DIAGNOSIS PEARLS

For Midline Radiolucencies:

1. Nasopalatine cyst - Oval/heart shape, above centrals
2. Median palatine cyst - Posterior to nasopalatine
3. Central giant cell granuloma - More aggressive, may show septations

For Interradicular Radiolucencies:

1. Globulomaxillary cyst - Classic pear shape
2. Lateral periodontal cyst - More cervical location
3. Radicular cyst - Associated with non-vital tooth

Infective osteomyelitis

• Tuberculous osteomyelitis
• Syphilitic osteomyelitis
• Actinomycotic osteomyelitis

Tuberculous osteomyelitis

• Non healing sinus tract formation
• Age group affected is around 15 – 40 years.
• Commonly seen in phalanges and dorsal and lumbar vertebrae.
• Usually occurs secondary to tuberculosis of lungs.
• Cases have been reported where mandibular lesions were not associated with pulmonary disease.
• Another common entrance is through a carious tooth via open pulp.
• Usually affects long bones and rare in jaws.
• Results when blood borne bacilli lodge in cancellous bone. Usually in ramus , body of mandible. may mimic parotid swelling or submassetric abscess.

Syphilitic osteomyelitis

• Difficult to distinguish syphilitic osteomyelitis of the jaws from pyogenic osteomyelitis on clinical & radiographic examination.
• Main features are progressive course & failure to improve with usual treatment for pyogenic osteomyelitis.
• Massive sequestration may occur resulting in pathologic fracture.
• If unchecked, eventually causes perforation of the cortex.

Actinomycotic Osteomyelitis

• The organisms thrive in the oral cavity, especially tissues adjacent to mandible.
• May enter the bone through a fresh wound, carious tooth or a periodontal pocket at the gingival margin of erupting tooth.
• Soft or firm tissue masses on skin, which have purplish, dark red, oily areas with occasional zones of fluctuation.
• Spontaneous drainage of serous fluid containing granular material.
• Regional lymph nodes occasionally enlarged.
• Mimics parotitis / parotid tumors

• Derived from Reduced Enamel Epithelium (REE):

  • Dentigerous Cyst

  • Eruption Cyst

  • Paradental Cyst

• Derived from Rests of Serres (remnants of dental lamina):

  • Odontogenic Keratocyst (OKC)

  • Gingival Cyst of Newborn

  • Gingival Cyst of Adult

  • Lateral Periodontal Cyst

  • Glandular Odontogenic Cyst