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Differential Diagnosis of Skull and Spine Disorders

Lumps & Bumps of Pediatric Skull!!navigator!!

  1. CONGENITAL LESIONS
    1. Encephalocele
    2. Nasal glioma
    3. Dermoid
    4. Epidermoid cyst
    5. Hemangioma
    6. Vascular malformation: venous, lymphatic, sinus pericranii
    7. PHACE syndrome
  2. ACQUIRED LESIONS
    1. Rhabdomyosarcoma
    2. Fibrosarcoma
    3. Langerhans cell histiocytosis
    4. Metastatic neuroblastoma
    5. Infection: Pott puffy tumor
    6. Trauma: cephalohematoma

Sutural Abnormalities!!navigator!!

Wide Sutures

= >10 mm at birth, >3 mm at 2 years, >2 mm at 3 years of age; (sutures are splittable up to age 12–15; complete closure by age 30)

  1. NORMAL VARIANT
    in neonate + prematurity; growth spurts occur at 2–3 years and 5–7 years
  2. CONGENITAL UNDEROSSIFICATION
    osteogenesis imperfecta, hypophosphatasia, rickets, hypothyroidism, pyknodysostosis, cleidocranial dysplasia
  3. METABOLIC DISEASE
    hypoparathyroidism; lead intoxication; hypo- / hypervitaminosis A
  4. RAISED INTRACRANIAL PRESSURE
    Cause:
    1. Intracerebral tumor
    2. Subdural hematoma
    3. Hydrocephalus
      Age: seen only if <10 years of age
      Location: coronal >sagittal >lambdoid >squamosal suture
  5. INFILTRATION OF SUTURES
    Cause: metastases to meninges from
    1. Neuroblastoma
    2. Leukemia
    3. Lymphoma
    • poorly defined margins
  6. RECOVERY from
    1. Deprivational dwarfism
    2. Chronic illness
    3. Prematurity
    4. Hypothyroidism

Craniosynostosis

= CRANIOSTENOSIS = premature closure of sutures (closing normally at about 30 years of age)

Age: often present at birth; M÷F = 4÷1

Etiology:

  1. PRIMARY CRANIOSYNOSTOSIS
  2. SECONDARY CRANIOSYNOSTOSIS
    1. hematologic: sickle cell anemia, thalassemia
    2. metabolic: rickets, hypercalcemia, hyperthyroidism, hypervitaminosis D
    3. bone dysplasia: hypophosphatasia, achondroplasia, metaphyseal dysplasia, mongolism, Hurler disease, skull hyperostosis, Rubinstein-Taybi syndrome
    4. syndromes: Crouzon, Apert, Carpenter, Treacher-Collins, cloverleaf skull, craniotelencephalic dysplasia, arrhinencephaly
    5. microcephaly: brain atrophy / dysgenesis
    6. after shunting procedures

Types:

Sagittal suture most commonly affected followed by coronal suture

  1. Scaphocephaly = Dolichocephaly (55%): premature closure of sagittal suture (long skull)
  2. Brachycephaly = Turricephaly (10%): premature closure of coronal / lambdoid sutures (short tall skull)
  3. Plagiocephaly (7%): unilateral early fusion of coronal + lambdoidal suture (lopsided skull)
  4. Trigonocephaly: premature closure of metopic suture (forward pointing skull)
  5. Oxycephaly= Acrocephaly: premature closure of coronal, sagittal, lambdoid sutures (conical skull); most severe form of craniosynostosis
  6. Cloverleaf skull = Kleeblattschädel: intrauterine premature closure of sagittal, coronal, lambdoid sutures (3-fold bulging skull)
    May be associated with: thanatophoric dysplasia
  • sharply defined thickened sclerotic suture margins
  • delayed growth of BPD in early pregnancy

Wormian Bones!!navigator!!

[Ole Worm (1558–1654), Professor of Anatomy, Copenhagen]

= intrasutural ossicles in posterior sutures (lambdoid, posterior sagittal, temporosquamosal), normal up to 6 months of age (most frequently)

With >10 wormian bones an underlying pathologic process should be considered.

mnemonic: PORK CHOPS I

  • Pyknodysostosis
  • Osteogenesis imperfecta
  • Rickets in healing phase
  • Kinky hair syndrome
  • Cleidocranial dysostosis
  • Hypothyroidism / Hypophosphatasia
  • Otopalatodigital syndrome
  • Primary acroosteolysis (Hajdu-Cheney) / Pachydermoperiostosis / Progeria
  • Syndrome of Down
  • Idiopathic (normal variant)

Increased Skull Thickness!!navigator!!

  1. GENERALIZED
    1. Chronic severe anemia (eg, thalassemia, sickle cell dz)
    2. Cerebral atrophy following shunting of hydrocephalus
    3. Engelmann disease: mainly skull base
    4. Hyperparathyroidism
    5. Acromegaly
    6. Osteopetrosis
  2. FOCAL
    1. Meningioma
    2. Fibrous dysplasia
    3. Paget disease
    4. Dyke-Davidoff-Mason syndrome
    5. Hyperostosis frontalis interna = dense hyperostosis of inner table of frontal bone; M <F

mnemonic: HIPFAM

  • Hyperostosis frontalis interna
  • Idiopathic
  • Paget disease
  • Fibrous dysplasia
  • Anemia (sickle cell disease, iron deficiency, thalassemia, spherocytosis)
  • Metastases

Hair-on-end Skull

mnemonic: HI NEST

  • Hereditary spherocytosis
  • Iron deficiency anemia
  • Neuroblastoma
  • Enzyme deficiency: glucose-6-phosphate dehydrogenase deficiency → hemolytic anemia
  • Sickle cell disease
  • Thalassemia major

Leontiasis Ossea

= overgrowth of facial bones causing leonine (lionlike) facies

  1. Fibrous dysplasia
  2. Paget disease
  3. Craniometaphyseal dysplasia
  4. Hyperphosphatasia

Abnormally Thin Skull!!navigator!!

  1. GENERALIZED
    1. Obstructive hydrocephalus
    2. Cleidocranial dysostosis
    3. Progeria
    4. Rickets
    5. Osteogenesis imperfecta
    6. Craniolacunia
  2. FOCAL
    1. Neurofibromatosis
    2. Chronic subdural hematoma
    3. Arachnoid cyst

Inadequate Calvarial Calcification

  1. Achondroplasia
  2. Osteogenesis imperfecta
  3. Hypophosphatasia

Osteolytic Lesion of Skull!!navigator!!

  1. NORMAL VARIANT
    1. Emissary vein
      connecting venous systems inside + outside of skull
      • bony channel <2 mm in width
    2. Venous lake
      = outpouching of diploic vein
      • extremely variable in size, shape, and number
      • irregular well-demarcated contour
    3. Fossae lacunae = pacchionian granulations
      = agglomeration of hypertrophic arachnoid villi communicating with dural sinus
      Age:>18 months; usually adulthood
      • usually multiple “punched-out” lesions with irregular contour in parasagittal location

      Location: within 3 cm of superior sagittal sinus, anterior >posterior frontal bone
      Site: inner table >diploe >outer table
    4. Parietal foramina
      nonossification of embryonal rests in parietal fissure; bilateral at superior posterior angles of parietal bone; hereditary transmission
  2. TRAUMA
    1. Surgical burr hole
    2. Leptomeningeal cyst
  3. INFECTION
    1. Osteomyelitis
    2. Hydatid disease
    3. Syphilis
    4. Tuberculosis
  4. CONGENITAL
    1. Epidermoid / dermoid
    2. Neurofibromatosis (asterion defect)
    3. Meningoencephalocele
    4. Fibrous dysplasia
    5. Osteoporosis circumscripta of Paget disease
  5. BENIGN TUMOR
    1. Hemangioma
    2. Enchondroma
    3. Brown tumor
    4. Eosinophilic granuloma
  6. MALIGNANT TUMOR
    1. Solitary / multiple metastases
    2. Multiple myeloma
    3. Leukemia
    4. Neuroblastoma

Solitary Lytic Lesion in Skull

mnemonic: HELP MFT HOLE

  • Hemangioma
  • Epidermoid / dermoid
  • Leptomeningeal cyst
  • Postop, Paget disease
  • Metastasis, Myeloma
  • Fibrous dysplasia
  • Tuberculosis
  • Hyperparathyroidism
  • Osteomyelitis
  • Lambdoid defect (neurofibromatosis)
  • Eosinophilic granuloma

Multiple Lytic Lesions in Skull

mnemonic: BAMMAH

  • Brown tumor
  • AVM
  • Myeloma
  • Metastases
  • Amyloidosis
  • Histiocytosis

Lytic Area in Bone Flap!!navigator!!

mnemonic: “RATI”

  • Radiation necrosis
  • Avascular necrosis
  • Tumor
  • Infection

Button Sequestrum!!navigator!!

mnemonic: TORE ME

  • Tuberculosis
  • Osteomyelitis
  • Radiation
  • Eosinophilic granuloma
  • Metastasis
  • Epidermoid

Absent Greater Sphenoid Wing!!navigator!!

mnemonic: M FOR MARINE

  • Meningioma
  • Fibrous dysplasia
  • Optic glioma
  • Relapsing hematoma
  • Metastasis
  • Aneurysm
  • Retinoblastoma
  • Idiopathic
  • Neurofibromatosis
  • Eosinophilic granuloma

Absence of Innominate Line!!navigator!!

= OBLIQUE CAROTID LINE

= vertical line projecting into orbit (on PA skull film) produced by orbital process of sphenoid

  1. CONGENITAL
    1. Fibrous dysplasia
    2. Neurofibromatosis
  2. INFECTION
  3. TUMOR

Widened Superior Orbital Fissure!!navigator!!

mnemonic: A FAN

  • Aneurysm (internal carotid artery)
  • Fistula (cavernous sinus)
  • Adenoma (pituitary)
  • Neurofibroma

Tumors of Central Skull Base!!navigator!!

  1. DEVELOPMENTAL
    1. Encephalocele
  2. INFECTION / INFLAMMATION
    1. Extension from paranasal sinus / mastoid infection
    2. Complication of trauma
    3. Fungal disease: mucormycosis in diabetic, aspergillosis in immunosuppressed patient
    4. Sinus + nasopharyngeal sarcoidosis
    5. Radiation necrosis
  3. BENIGN
    1. Juvenile angiofibroma
    2. Meningioma
    3. Chordoma
    4. Pituitary tumor
    5. Paget disease
    6. Fibrous dysplasia
  4. MALIGNANT
    1. Metastasis: prostate, lung, breast
    2. Chondrosarcoma
    3. Nasopharyngeal carcinoma
    4. Rhabdomyosarcoma
    5. Perineural tumor spread: head + neck neoplasm

Craniofacial Syndromes!!navigator!!

= developmental malformations of the face + skull associated with CNS malformations

  1. Midfacial clefts
  2. Goldenhar syndrome
  3. Apert syndrome
  4. Crouzon syndrome
  5. Treacher-Collins syndrome

Outline