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Differential Diagnosis of Nervous System Disorders

Intracranial Calcifications!!navigator!!

mnemonic: PINEEAL

  • Physiologic
  • Infection
  • Neoplasm
  • Endocrine
  • Embryologic
  • Arteriovenous
  • Leftover Ls
  1. PHYSIOLOGIC INTRACRANIAL CALCIFICATIONS
  2. INFECTION
    TORCH (toxoplasmosis, others [syphilis, hepatitis, zoster], CMV, rubella, herpes), healed abscess, hydatid cyst, granuloma (tuberculoma, actinomycosis, coccidioidomycosis, cryptococcosis, mucormycosis), cysticercosis, trichinosis, paragonimiasis
    mnemonic:
  3. NEOPLASM
    Craniopharyngioma (40–80%), oligodendroglioma (50–70%), chordoma (25–40%), choroid plexus papilloma (10%), meningioma (20%), pituitary adenoma (3–5%), pinealoma (10–20%), dermoid (20%), lipoma of corpus callosum, ependymoma (50%), astrocytoma (15%), after radiotherapy, metastases (1–2%, lung >breast >GI tract)
    N.B.: Astrocytomas calcify less frequently but are the most common tumor!
  4. ENDOCRINE Hyperparathyroidism, hypervitaminosis D, hypoparathyroidism, pseudohypoparathyroidism, CO poisoning, lead poisoning
  5. EMBRYOLOGIC
    Neurocutaneous syndromes (tuberous sclerosis, Sturge-Weber, neurofibromatosis), Fahr disease, Cockayne syndrome, basal cell nevus syndrome
  6. ARTERIOVENOUS Atherosclerosis, aneurysm, AVM, occult vascular malformation, hemangioma, subdural + epidural hematomas, intracerebral hemorrhage
  7. LEFTOVER Ls
    Lipoma, lipoid proteinosis, lissencephaly

Physiologic Intracranial Calcification

  1. Pineal calcification
    Age: no calcification <5 years of age, in 8–10% at 8–14 years of age, in 40% by 20 years of age; in ⅔ of adult population
    • amorphous / ringlike calcification <3 mm from midline usually <10 mm in diameter
    • ~ 30 mm above highest posterior elevation of pyramids

    CAVE: pineal calcification >14 mm suggests pineal neoplasm (teratoma / pinealoma)
  2. Habenula
    Frequency: ~ in ⅓ of population
    Age:>10 years of age
    • posteriorly open C-shaped calcification 4–6 mm anterior to pineal gland
  3. Choroid plexus
    may calcify in all ventricles: most commonly in glomus within atrium of lateral ventricles, near foramen of Monro, tela choroidea of 3rd ventricle, roof of 4th ventricle, along foramina of Luschka
    Age:>3 years of age
    • 20–30 mm behind + slightly below pineal on lateral projection, symmetrical on AP projection

    DDx: neurofibromatosis
  4. Dura, falx cerebri, falx cerebelli, tentorium
    Frequency: 10% of population
    Age:>3 years of age
    DDx: basal cell nevus syndrome (Gorlin syndrome), pseudoxanthoma elasticum, congenital myotonic dystrophy
  5. Petroclinoid ligament (= reflection of tentorium between tip of dorsum sellae and apex of petrous bone)
    Age:>5 years of age
  6. Interclinoid ligament
    = interclinoid bridging
  7. Arteriosclerosis: particularly intracavernous segment of ICA, basilar a., vertebral a.
  8. Basal ganglia

Increased Density of Falx!!navigator!!

  1. Subarachnoid hemorrhage
  2. Interhemispheric subdural hematoma
  3. Diffuse cerebral edema (= increased density relative to low-density brain)
  4. Dural calcifications (hypercalcemia from chronic renal failure, basal cell nevus syndrome, hyperparathyroidism)
  5. Normal falx (can be normal in pediatric population)

Intraparenchymal Hemorrhage!!navigator!!

mnemonic: “ITHACANS”

  • Infarction (hemorrhagic)
  • Trauma
  • Hypertensive hemorrhage
  • Arteriovenous malformation
  • Coagulopathy
  • Aneurysm, Amyloid angiopathy
  • Neoplasm: metastasis / primary neoplasm
  • Sinus thrombosis

Dense Cerebral Mass!!navigator!!

Substrate: calcification / hemorrhage / dense protein

  1. VESSEL
    1. Aneurysm
    2. Arteriovenous malformation
    3. Hematoma (acute / subacute)
  2. TUMOR
    1. Lymphoma
    2. Medulloblastoma
    3. Meningioma
    4. Metastasis
      1. from mucinous-producing adenocarcinoma
      2. hemorrhagic metastases: melanoma, choriocarcinoma, hypernephroma, bronchogenic carcinoma, breast carcinoma (rarely)

Outline