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Background Gross Pathology Histopathology & Immunohistochemistry Reference

BACKGROUND AND CLINICAL INFORMATION: Head

Summary: Fetal alcohol syndrome is resulted from the teratogenic effects of alcohol on human fetuses. The classic cases have the clinical triad of growth retardation, characteristic facial dysmorphology and dysfunction of the central nervous system. The degree of involvement is highly variable.

Etiology: In utero exposure to alcohol.

Definition:

Fetal alcohol syndrome (FAS): Patients must have all three chraracteristics: prenatal and postnatal growth retardation (<2 SD for length and weight), characteristic facial features, and CNS dysfunction.
Fetal alcohol effect (FAE): When the features of the syndrome are not fully expressed, the term fetal alcohol effects (FAE) can be used.

Diagnostic criteria: [Rosett HL, 1980]

Prenatal and/or postnatal growth retardation (weight, length, and/or head circumference below the 10^th percentile).
Characteristic facial dysmorphology with at least two of these three signs: microcephaly (head circumference below the 3^rd percentile), microophthalommia and/or short palpebral fissures, and poorly developed philtrum, thin upper lip, and flattening of the maxillary area.
Central nervous system involvement (signs of neurological abnormality, developmental delay, or intellectual impairment).

Clinical category: [Stratton KR et al., 1996]

Diagnostic features:

Growth retardation: Patients remained more than 2 standard deviations below the norm. Some patients may have postnatal catch-up growth.
Characteristic facial features: The facial features are mainly hypoplastic in nature. These features include short palpebral fissures (small opening of the eye, seen in 91% of FAS patients), maxillary hypoplasia with relative prognathism, epicanthal folds, thinning of vermilion border and hypoplastic upper lip, low nasal bridge and anteverted nostrils, hypoplastic upper helix, and apparent hypertelorism due to short palpebral fissure (blepharophimosis).
CNS dysfunction: Mental retardation in 85% of patients, irritability and poor suck in the newborn period, hypotonia, hypertonia, seizures and hyperactivity.

GROSS PATHOLOGY: Head

Microcephaly is the most consistent finding. The basal ganglia, especially the caudate, is greatly reduced in size; the cerebellum is also small. Agenesis of corpus callosum or small corpus callosum are common.

HISTOPATHOLOGY AND IMMUNOHISTOCHEMISTRY: Head

Architectural change: There are no consistent architectural changes of the CNS but neuronal migration may be more commonly seen. Various migration disorders including lissencephaly, polymirogyria, neuronal heterotopia, leptomeningeal glioneuronal heterotopias. Other pathologic changes that have been described include hydrocephalus, neural tube defects, various migration disorders of cerebrum and hindbrain, septo-optic dysplasia and holoprosencephaly.

REFERENCES: Head

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Background Gross Pathology Histopathology & Immunohistochemistry Reference