| Anatomical Site | Frequency/Prevalence | Typical Age of Onset | Key Clinical Features | Primary Diagnostic Modality | Primary Treatment |
|---|---|---|---|---|---|
| Ovarian (mature cystic teratoma / dermoid cyst) | Ovarian germ cell tumors represent ~2–5% of ovarian cancers; mature teratoma is the benign teratoma subtype and one of the common ovarian germ-cell lesions in children, adolescents, and young adults (pqac-00000009, pqac-00000012) | Usually reproductive age; often children, adolescents, and young adults for ovarian germ-cell tumors (pqac-00000012) | Often asymptomatic until large; may present with adnexal mass, pelvic pain, torsion, rupture, or rarely malignant transformation; histologically a mature teratoma is a dermoid cyst (pqac-00000008, pqac-00000009) | Pelvic ultrasound first-line; CT/MRI used for characterization of fat/calcification and complications; definitive diagnosis by histopathology after excision (pqac-00000008) | Surgical excision, usually fertility-sparing cystectomy/oophorectomy; laparoscopy commonly used when feasible (pqac-00000016) |
| Intracranial | Rare benign tumor comprising ~0.04–0.6% of brain tumors (pqac-00000000) | Congenital in origin but often diagnosed in young adults, especially ages 20–30 for suprasellar supratentorial lesions; can occur from childhood to adulthood (pqac-00000000, pqac-00000007) | Headache, seizures, dizziness/vertigo, visual symptoms; rupture may cause chemical aseptic meningitis and acute symptomatic seizures (pqac-00000000, pqac-00000007) | MRI is primary and essential for diagnosis and surgical planning; CT may assist in lesion characterization (pqac-00000007, pqac-00000018) | Neurosurgical excision aiming for gross total resection when safely possible; subtotal resection may be necessary near critical neurovascular structures (pqac-00000018, pqac-00000019) |
| Nasal / craniofacial | Nasal dermoids account for at least 60% of congenital developmental midline nasal masses; intracranial involvement occurs in ~20% overall, with wide reported range (4–57%) (pqac-00000004) | Congenital; usually recognized in infancy or childhood (pqac-00000001, pqac-00000004) | Painless noncompressible midline nasal mass; sinus opening with visible hair may be present; recurrent local infection possible, with substantial childhood infection risk when a sinus ostium is present (pqac-00000001, pqac-00000004) | MRI preferred for defining soft-tissue tract and intracranial extension; CT complements osseous assessment; biopsy is contraindicated (pqac-00000003, pqac-00000006) | Complete surgical excision of cyst and tract; external rhinoplasty, endoscopic, or combined craniofacial approaches depending on extension (pqac-00000015, pqac-00000021) |
| Orbital / periorbital | Common congenital craniofacial dermoid location; literature in this evidence set is mainly case-series/review based rather than population-based, so precise prevalence not established here (pqac-00000007, pqac-00000015) | Usually congenital and detected in infancy or childhood (pqac-00000015) | Superolateral brow/orbital mass, usually painless and slowly enlarging; cosmetic deformity, local pressure effects, and occasional rupture/inflammation may occur (pqac-00000015, pqac-00000016) | Clinical examination with imaging when deep lesion suspected; MRI/CT used to define orbital extension and surgical anatomy (pqac-00000016) | Complete surgical excision; careful removal needed to avoid rupture and recurrence (pqac-00000016) |
| Cutaneous / subcutaneous | Developmental anomaly rather than true neoplasm; human population prevalence not well defined in this evidence set (pqac-00000002, pqac-00000005) | Congenital, though superficial lesions may be recognized later depending on size/location (pqac-00000002) | Small dermal/subcutaneous cyst containing keratin, hair, and sebaceous material; often solitary, slow-growing, and sometimes with a surface pore or protruding hair (pqac-00000002, pqac-00000005) | Clinical examination with confirmation by histopathology after excision; imaging only if deep extension suspected (pqac-00000002, pqac-00000005) | Complete surgical excision (pqac-00000005) |
| Limbal / epibulbar | Rare ocular surface choristoma/dermoid subtype; no robust prevalence estimate in this evidence set (pqac-00000016) | Congenital, typically identified in childhood (pqac-00000016) | Visible limbal or epibulbar mass; may induce astigmatism, visual disturbance, irritation, or cosmetic concern (pqac-00000016) | Ophthalmologic slit-lamp examination; imaging used selectively for extent/depth; diagnosis confirmed clinically and histopathologically when excised (pqac-00000016) | Observation for small asymptomatic lesions or surgical excision/lamellar keratoplasty/corneal autograft in visually significant cases (pqac-00000016) |


*Table: This table summarizes how dermoid cysts differ by anatomical site, including frequency, age at presentation, clinical features, diagnostic approach, and treatment. It is useful for comparing the major clinically relevant dermoid cyst subtypes in one place.*