⭐ GORLIN SYNDROME (Basal Nevus Cell Carcinoma Syndrome)
Gorlin syndrome is an autosomal dominant neurocutaneous (phakomatosis) disease characterized by a triad of multiple basal cell nevi, jaw odontogenic keratocysts, and skeletal anomalies.
🔹An odontogenic (primordial) keratocyst is a cyst that arises from a tooth before its calcification.
🔹It is most commonly located posterior to the premolar region of the mandible or maxilla.
🔹In the mandible, it mostly affects the third molar tooth.
🔹In men, the disease causes hypogonadism, while in women it causes calcified ovarian fibroids.
📌 To diagnose Gorlin syndrome, two major or one major and two minor diagnostic criteria are needed:
💡 Major diagnostic criteria:
🔺A patient under 20 years of age with basal cell carcinoma or more than two basal cell carcinomas in older age.
🔺Histologically proven odontogenic keratocysts of the jaw.
🔺More than three palmar pits.
🔺Bifid or fused ribs.
🔺First-degree relative with basal nevus cell carcinoma.
💡 Minor diagnostic criteria:
🔺 Macrocephaly.
🔺 Medulloblastoma.
🔺 Calcified ovarian fibroids.
🔺 Sprengel deformity or syndactyly.
🔺 Vertebral anomalies or bridging of the sella turcica.
🔺 Hypertelorism, cleft-lip, or frontal bossing.
🔺 Cardiac fibromas.
⭐ PAGET DISEASE (Ostitis Deformans)
Paget disease (PD) of bone is a progressive chronic disease of unknown origin characterized by abnormal bone remodeling.
🔹In PD, there is abnormal activity of the osteoblasts and osteoclasts resulting in phases of bone destruction (osteolytic phase) followed by bone restoration and repair (reparative phase); the net result is a brittle, sclerotic bone.
🔹The disease has an incidence of 3% in the population over 40 years of age. PD commonly affects the axial skeleton. The fibula is the only bone in the body that is rarely affected in PD.
🔹Clinically, PD presents as an incidental finding of abnormally high serum alkaline phosphatase in the absence of liver disease, often in an asymptomatic patient.
🔹PD pain is usually localized to an area of a bone currently undergoing metabolic changes.When the pain is localized to a joint that worsens by movement, it is against the typical features of PD.
🔹Complications of PD are related to the phases of osteolytic and sclerotic bone changes.They include nerve compression syndrome, hearing loss when it affects the petrous bone, pathological fractures, and spinal canal stenosis.
💡Signs on Radiographs
– Thickening of the iliopectineal line in the pelvis.
– Thickening of the skull base, with pathognomonic “cotton wool appearance ” of the skull due to mixed lytic/sclerotic activities in the flat bones.
– PD in the long bones always starts from the ends (subcortical bone) to the center (diaphysis); an exception to this rule occurs in the tibia. If the lesion is only located in the midshaft, then it is not PD.
🔸Osteoporosis Circumscripta: is a term describing the osteolytic phase of PD when it affects the skull. It affects mostly the frontal and occipital bones.
🔸Ivory vertebra: is a term used to describe complete sclerosis of the vertebral body. It is typically seen in PD, metastasis, and lymphoma.
⭐ RANULA
🔹The sublingual glands have 8–20 excretory ducts that open below the tongue posterior to the opening of the submandibular duct (of Warton).
🔹Ranula is a retention cyst of the minor salivary gland or the sublingual glands occurring most commonly after trauma or inflammation of the mouth; congenital ranulas are rare.
🔹Typically, the patient is between 25 and 30 years of age with 50% having a history of previous trauma to the mandible.
🔹Ranulas are divided into two types:
🔸Simple ranula: occurs due to obstruction of the salivary gland duct without rupturing. It does not cross the boundaries of the submandibular space.
🔸Complicated (diving) ranula: results from rupture of the gland within the sublingual space with formation of a pseudocyst that can extend into the submandibular space.
🔹Patients often present with painless swelling of the sublingual glands with bluish discoloration
💡Signs On CT
🔸Simple ranula: the scan shows a hypodense mass located in the sublingual space with a ring enhancement after contrast material injection.
🔸Complicated ranula appears as a “comet-tail-shaped mass.” The tail is located in the sublingual space and the head is in the submandibular space
💡Signs On MRI
– The cyst has low T1/high T2 signal intensities with a homogeneous internal architecture. An inhomogeneous internal architecture excludes the diagnosis of ranula.
– The comet-tail sign is seen as a high fluid signal on T2-weighted images within the sublingual space.
– Extension of the ranula may reach the submandibular space, or further upward into the parapharyngeal space. This free extension occurs because there are no fascial boundaries between the sublingual, submandibular, and parapharyngeal spaces.
⭐ DENTIGEROUS (FOLLICULAR) CYSTS
🔹A dentigerous cyst is one that arises from a tooth after calcification of its crown and is usually located at the mandibular or the maxillary third molar tooth.
🔹The cyst can be large enough to occupy half of the mandible.
🔹The peak incidence is between 40 and 60 years of age.
🔹Dentigerous cysts can be associated with mucopolysaccharidosis.
💡Signs on Radiograph or CT
A cystic lesion of the mandible with an eccentrically placed tooth crown.
⭐ DERMOID AND EPIDERMOID CYSTS
🔹These lesions are commonly located medially within the neck, and characteristically have thick walls.
🔹They are typically midline lesions arising from the floor of the mouth deep to the myelohyoid muscle.
🔹Dermoid cysts contain skin, sebaceous glands, and hair follicles.
🔹In contrast, epidermoid cysts contain fluid but not fatty material.
💡Signs on CT and MRI
– These lesions are commonly located medially within the neck and have thick walls.
– On MRI, globules of floating fat within the lesion can produce a characteristic “sack of marbles ” appearance or fat–fluid levels.
– They can be mistaken for thyroglossal cyst.
⭐ THYROGLOSSAL DUCT CYST
🔹The thyroid gland develops medially at the base of the tongue and then descends anterior to the hyoid bone along the thyroglossal duct to its normal position.
🔹When the thyroglossal duct fails to obliterate, it results in the formation of a median or paramedian cyst.
🔹The normal thyroglossal duct extends from the foramen cecum at the base of the tongue to the lower neck region where the thyroid bed is.
🔹It is obliterated between the fifth and sixth weeks of gestation.
🔹Thyroglossal duct cysts account for up to 70% of all cystic malformations in the neck.
🔹Up to 50% are located at the hyoid bone, 25% below the hyoid and 25% above it.
💡Signs on CT
– Typically, the scan shows a median–paramedian cyst located at the level of the hyoid bone with no contrast enhancement.
– The cyst typically splits the two anterior bellies of the digastric muscles.
– Ring contrast enhancement may be seen in cases of infected cyst.
⭐ GARDNER SYNDROME
🔹Gardner syndrome is a rare, hereditary disease characterized by intestinal polyposis (made of adenomas), multiple osteomas (mainly in the jaw), and multiple cutaneous and subcutaneous lesions (epidermoid cysts and desmoid tumor).
🔹The intestinal polyposis is hereditary with a 100% chance of malignant transformation if not treated.
🔹Osteoma is a benign bony island that can be made up of compact (ivory) or trabecular bone.
🔹In Gardner syndrome, osteomas are commonly found in the jaw and the skull. In the jaw, the most characteristic and diagnostic locations for Gardner syndrome osteomas are the mandibular angle or its inferior surface.
🔹Mandibular osteomas can be the initial sign and symptom of Gardner syndrome.
🔹The disease commonly presents with dental abnormalities (30%) such as dental hypoplasia, supernumerary teeth, and compound odontomas.
🔹Epidermoid cysts present in the face, scalp, and extremities in around 50% of cases.
🔹Desmoid tumor is a benign fi brous soft-tissue proliferation that occurs in the skin or inside the abdomen.
🔹It has no malignant tendency; however, it has an aggressive infiltration of the adjacent tissues and tends to reoccur after surgical excision.
🔹It is seen in 8.9% of cases.
🔹Congenital Hypertrophy of the Retinal Pigment Epithelium (CHRPE) can be seen in up to 85% of cases.
💡Signs on Plain Radiographs
– Osteomas of the skull, angle of the mandible, or its inferior surface.
– Dental anomalies, hypoplasia, and unruptured teeth.
– Cortical thickening (hyperostosis) in the long bones.