| Condition/Pathology | Type of Disorder | Clinical Features | Cause / Etiology | Histological Features |
| Cleft Lip and Cleft Palate | Developmental Abnormality | Most common developmental facial abnormality. Openings between oral and nasal cavities, causing feeding/speech problems. Can be unilateral, bilateral, partial, or complete. | Failure of fusion of embryological processes. Caused by inheritance and environmental teratogens (drugs, alcohol, smoking, chemicals). | Not specified in the text. |
| Bifid Uvula and Bifid Tongue | Developmental Defect | Uvula or tongue appears split in two. Often an incidental finding. Bifid uvula can cause swallowing disturbances. “Artificial” bifid tongue can result from piercing trauma. | Incomplete fusion of embryonic processes. | Not specified in the text. |
| Lip Pits | Congenital Anomaly | Small (1-4 mm deep), sac-like invaginations of lip mucosa on the vermilion border. Usually asymptomatic and incidental. | Congenital. | Not specified in the text. |
| Double Lip | Rare Anomaly | An excess fold of tissue on the inner aspect of the lip, most commonly the upper lip. | Not specified in the text. | Not specified in the text. |
| Aglossia & Ankyloglossia | Developmental Defect | Aglossia: Partial or complete absence of the tongue. Ankyloglossia (Tongue Tie): Anterior tongue attached to the floor of the mouth by a tight frenum, limiting movement and causing speech/swallowing issues. | Aglossia: Failure of fusion of branchial arches. Ankyloglossia: Tight cord of tissue (frenum). | Not specified in the text. |
| Macroglossia & Microglossia | Congenital or Acquired Disorder | Macroglossia: Abnormally large tongue; may show scalloping on lateral borders. Microglossia: Abnormally small tongue. Both can affect speech, feeding, and dental alignment. | Macroglossia: Can be congenital (e.g., Down syndrome) or from neoplasia. Microglossia: Lack of development of tongue structures. | Not specified in the text. |
| Fissured Tongue | Common Condition | Deep grooves on the dorsum of the tongue. Prevalence of 5% to 30%. Can trap food/debris, leading to inflammation and halitosis. | Not specified in the text. | Not specified in the text. |
| Lingual Thyroid (Ectopic Thyroid) | Developmental Anomaly (Choristoma) | Mucosal-colored round nodule (up to 4 cm) on the dorsum of the tongue, at or near the terminal sulcus. | Normal thyroid tissue that failed to migrate from its initial site (foramen caecum). | Normal thyroid tissue. |
| Lingual Varicosities | Developmental Anomaly | Non-painful, large, dilated, blue masses on the ventral (underside) surface of the tongue. More common in older individuals. | Swollen, twisted veins filled with an abnormal collection of blood. | Not specified in the text. |
| White Sponge Nevus | Genetic Nevus | Persistent, non-wipeable, white/grey, thickened, spongy lesions on oral mucosa (buccal is common). Noted in the first two decades of life. | Genetic mutation affecting specific cytokeratins. | ”Spongy” epithelium with intracellular vacuolation (watery degeneration) sparing basal cells. Pathognomonic feature: Perinuclear eosinophilic condensation. |
| Fordyce Granules (Sebaceous Hyperplasia) | Normal Anatomical Variation | 1-3 mm yellowish papules on posterior buccal mucosa and lips. Seen in 60-80% of adults. Considered normal structures. | Ectopic sebaceous glands in the oral mucosa. | Mature sebaceous glands. Hyperplasia: ≥15 lobules opening into a central duct. |
| Congenital Granular Cell Tumor (Epulis) | Developmental Disorder | A mesenchymal tumor occurring in newborns with a strong female predilection (8-10:1). | Believed to be of neural crest origin; considered a developmental disorder rather than a true neoplasm. | Sheets of cells with pale, granular cytoplasm; prominent arborizing vessels; atrophic epithelium with no pseudoepitheliomatous hyperplasia. |
| Osseous, Cartilaginous, and Osteochondromatous Choristoma | Choristoma | A mass or nodule, usually on the dorsum of the tongue (>90%). Seen in young adults with a 2:1 female predilection. Can cause a lump sensation or dysphagia. | Overgrowth of mature bone/cartilage in an area where it is not normally found. | Mass of mature lamellar bone with widely spaced osteocytes and osteoblastic rimming, within a cellular fibrous tissue. |
| Leiomyomatous Hamartoma | Hamartoma | A soft, painless polypoid mass seen in the first year of life. Usually on the tongue or anterior maxillary/palatal mucosa. | Overgrowth of mature smooth muscle tissue that is normally found in that area. | Nonencapsulated, discrete proliferation of fusiform smooth muscle cells. Cells express muscle-specific actin and desmin, but not S100 protein. |