piriform sinus fistula
persistence of remnants of the ultimopharyngeal body along its path to the thyroid gland
what are branchial vestiges?
cartilaginous or bony remnants of pharyngeal arch cartilages that appear under the skin in the side of the neck
1st arch syndrome: in general, what is it and what causes it?
congenital anomalies of eyes, ears, mandable, and palate -caused by insufficient migration of neural crest cells into 1st arch during 4th week
what are the two main manifestations of 1st arch syndrome?
- Treacher Collins syndrome
2. Pierre Robin sequence
what is Treacher Collins syndrome?
mandibulofascial dysostosis, autosomal dominant:
- malar hypoplasia
- down slanting palpebral fissures
- defects of lower eyelid
- deformed external ears
- some abnormalities of middle/internal ears
what is the mutation associated with Treacher Collins syndrome?
mutation in TCOF1, which makes the protein treacle
what is Pierre Robin syndrome?
autosomal recessive:
- hypoplasia of mandible (micrognathia)
- cleft palate
- defects of eye, ear
what is DiGeorge syndrome?
- lack of thymus and parathyroid glands
- defects in cardiac outflow tracts
- lack of T cell fxn
- low set ears
- shortened philtrum of upper lip (fish mouth deformity)
what causes DiGeorge syndrome?
3rd and 4th pharyngeal pouches fail to differentiate into thymus and parathyroid glands
what is the most common metabolic disorder in neonates?
congenital hypothyroidism
what is ankyloglossia?
short frenulum that extends to the tip of the tongue - interferes with its free protrusion, makes breast feeding difficult
what is macroglossia?
excessively large tongue from hypertrophy of developing tongue - often seen in Down syndrome
what is microglossia?
abnormally small tongue (rare) - usually associated with micrognathia and limb defects
what is glossoschisis?
bifid or cleft tongue - incomplete fusion of lateral lingual swellings (uncommon)
what is atresia of nasolacrimal duct?
when part of the nasolacrimal duct fails to canalize
congenital auricular sinuses or cysts
located in a triangular area of skin anterior to auricle or external ear - minor anomaly
what is congenital microstomia?
small mouth from excessive merging of mesenchymal masses in the maxillary and mandibular processes of the first pharyngeal arch
what are oblique facial clefts?
- extend from upper lip to medial margin of orbit
- often bilateral
- nasolacrimal ducts are open grooves
what are lateral or transverse facial clefts?
-run from mouth toward ear
what is macrostomia?
large mouth - results from bilateral facial clefts
what is cyclopia?
- single median eye enclosed in a single orbit
- usually have a tubular nose (proboscis) superior to eye
what is synophthalmia?
fusion of eyes
what is microphthalmia?
small eyes associated w/ other ocular defects
severe vs. simple microphthalmos
severe -from arrested development of eye before or shortly after the optic vesicle has formed in 4th week
simple - development arrested in 8th week
what is anophthalmia?
absence of an eye (unilateral or bilateral)
-eyelids form, but no eye present
primary vs. secondary anophthalmos
primary: eye development arrested in 4th week, results from failure of optic vesicle to form
secondary: development of forebrain suppressed -> includes many other defects
what determines iris color?
concentration and distribution of chromatophores in the loose vascular CT of iris
what is congenital aniridia?
lack of iris tissue or almost complete absence of iris - from arrested development at rim of optic cup (mutation in Pax6)
what is persistent pupillary membrane?
web-like strands of CT or vascular arcades over the pupil
-especially in premies
what is congenital atresia of the pupil?
entire pupillary membrane persists - absence of opening of pupil
what is congenital aphakia?
absence of the lens
what is congenital cataracts?
- opaque, grayish white lens
- untreated = blindness
- can be caused by rubella virus or congenital galactosemia
what is cryptophthalmos?
congenital absence of the eyelids -> skin covers eyes
-autosomal recessive
what are auricular appendages?
skin tags usually anterior to auricle - usually unilateral
-consist of skin
what is anotia?
absence of the auricle - failure of mesenchymal proliferation
what is microtia?
small or rudimentary auricle - from suppressed mesenchymal proliferation
what causes atresia of the external acoustic meatus?
failure of the meatal plug to canalize
what causes absence of external acoustic meatus?
failure of inward expansion of the 1st pharyngeal groove and failure of meatal plug to disappear
what is congenital cholesteatoma?
fragment of keratinized epithelial cells “rest” that appears as a white cyst-like structure medial to and behind the tympanic membrane