Chapter 50 - Congenital Malformations H/N Flashcards
Lymphatic malformations: tumors? do they expand?
not true tumors - grow with patient
can rapidly expand with infection, bleeding, trauma
branchial cleft: deep to which arch? superficial to which?
anomalies track deep to structures of own arch, superficial to structures of next one
most common congenital neck mass
thyroglossal duct cyst
how does thyroglossal duct cyst form?
3 wk gestation thyroid gland forms from diverticulum at tongue (foramen cecum)
descends to fuse with 4th-5th pouch components
5-8wk: tract formed by descent obliterates, forming foramen cecum proximally and pyramidal lobe thyroid distally
Incomplete obliteration –> TDC
Classic TDC PE sign
elevates with tongue protrusion
Critical preop imaging prior to TDC removal
U/S to r/o ectopic thyroid
DDx and defining characteristics of midline CONGENITAL neck masses
TDC - elevate with swallow
Dermoid - submental, move with skin
Teratoma - firm, CT with calcification, rare, larger/more sx than dermoid
Plunging ranula - midline, cystic, extends to FOM
DDx and defining characteristics of lateral CONGENITAL neck masses
branchial cleft cyst - deep to ant border SCM, fluctuant
lymphangioma - soft, compressible, transilluminate
external laryngocele - air filled, protrude through thyrohyoid, hoarse, cough
SCM tumor - firm, painless, discrete, fusiform mass
Recurrence rate of TDC after Sistrunk
2.6-5%
Can TDC’s harbor malignancy?
Yes - well differentiated thyroid CA
Sistrunk removal offers excellent cure rate
Describe sistrunk procedure objectives
remove TDC tract connecting it to the foramen cecum
remove central portion of hyoid
Dermoid vs teratoma
Dermoid- ectoderm/mesoderm only, from entrapped epithelium along lines of embryonic fusion, enlarge over time, cheesy contents upon excision, fill with sebaceous material
Teratoma- all 3 germ layers, larger/typically more Sx, dx by prenatal u/s often, 30% associated with polyhydramnios (esophageal obstruction)
Branchial cleft vs arch vs pouch
At 4wk geswtation, there are 4 pairs of arches, and two rudimentary ones
External lining ectoderm, internal endoderm, meso between
arches separated by pouches internally and clefts externally
clefts and pouches gradually replaced with mesenchyme
when clefts and pouches persist –> branchial anomaly
3 types of branchial anomaly
remember this is when clefts/pouches persist
Cyst- remnant with no openings, squamous lining
Sinus- iexternal opening (often drain to skin), often lined with ciliated columnar
Fistula- internal (aerodigestive tract) and external (skin) opening
Type 1 BA
1% (rare) between EAC and submandibular area lateral to VII duplication of EAC can terminate in EAC or middle ear Do not contain mesoderm
Type 2 BA
95% MEDIAL to VII and has mesoderm Anterior border SCM Between ICA and ECA Terminate in tonsillar fossa (but can terminate in EAC/middle ear)
Type 3/4 BA
present lower than type 2 but also along anterior SCM border
terminate ipsilateral pyriform sinus
tract of type 4 loops under subclavian (R) or under aortic arch (L)
Arch 1 artery, nerve
terminal br maxillary
V
Arch 1 skeletal elements
incus, malleus, Meckel’s cartilage, upper portion auricle, maxilla, zygomatic, squamous portion of T bone, mandible
Arch 1 mm
mastication, mylo, anterior dig, TT, TVP
Arch 2 arteries, n
stapedius (embryologic), corticotympanic (adult)
VII
Arch 2 skeletal elements
stapes, styloid, stylohyoid ligament, lesser horns and upper rim hyoid, lower auricle
Arch 2 mm
facial expression, posterior dig, stylohyoid, stapedius
Arch 3 a, n
common carotid, most of internal carotid
IX
Arch 3 skeletal
lower rim, greater horn hyoid