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Proboscis lateralis describes a rudimentary nasal structure or appendage
that is located off-center from the vertical midline of the face. Proboscis
lateralis is a rare craniofacial malformation frequently associated with abnormalities
of the eyes and/or ocular adnexa. We report a case with ipsilateral colobomatous
microphthalmia and choanal atresia.
A 3.5-kg black male infant was born at 40 weeks' gestation by uncomplicated
spontaneous vaginal delivery with Apgar scores of 8 and 9 at 1 and 5 minutes.
At birth, the patient was noted to have a 2.5 × 1.1-cm trunk-like appendage
(Figure 1) arising from his left
medial canthus with a clear mucoid discharge draining from an orifice at its
distal end. Also noted were left microphthalmos, left choanal atresia, and
a mildly hypoplastic left nasal ala. Prenatal history was negative for consanguinity,
exposure to alcohol, ionizing radiation, prescription medications, or recreational
drugs. The patient's mother denied any family history of blindness, craniofacial
abnormalities, mental retardation, or other congenital defects. Chromosomal
analysis was reported as 46, XY. Findings from examination of the left eye
were remarkable for microphthalmia with a horizontal corneal diameter of 5.0
mm. The anterior chamber was well formed and the lens was clear. Funduscopic
examination results were remarkable for a posterior chorioretinal coloboma
with a partial retinal detachment. Findings from examination of the right
eye were normal.
Proboscis with metal/ skin hook
inserted into the distal orifice. Note the slightly hypoplastic left nasal
ala and obvious microcornea of the small left eye.
Computed tomographic images (Figure
2 and Figure 3) demonstrated
normal cerebral parenchyma, ventricular architecture, and mid-line anatomy.
Hypoplasia of the left nasal passage with left-sided choanal atresia was present.
A defect in the medial wall of the left orbit was noted, and a tubular soft
tissue structure extended from the medial aspect of the preseptal soft tissue
and appeared continuous with the nasal cavity and ethmoid sinus. The left
globe was small and dysplastic with a colobomatous cyst posteriorly.
Axial 1.5-mm contrast-enhanced
computed tomographic scan, bone windows. A, Left-sided choanal atresia (arrow).
B, Portion of the proboscis on the left (open arrow) with a pneumatized central
canal. The soft tissue extends through a defect (arrow) in the medial wall
of the left orbit, continuous with the ethmoid sinus.
Axial 1.5-mm contrast-enhanced
computed tomographic scan, soft tissue windows. A, Cross-sectional view of
mid portion of tubular proboscis (open arrow). B, Oblique view closer to the
base of the proboscis, which protrudes from soft tissue adjacent to the medial
canthus. Note air in the central canal (open arrow). The left globe is microphthalmic,
and a colobomatous defect (arrow) is present with a cystic mass extending
Surgical excision of the proboscis was performed at age 4 months. Since
the nasal alae were relatively well developed, reconstruction was unnecessary,
and the soft tissue appendage was simply amputated from its origin at the
superior aspect of the left medial canthus. The fistulous tract to the ethmoid
sinus was excised, and the choanal atresia was then repaired.
Pathologic findings revealed an oblong, skin-covered, tubular mass (Figure 4) measuring 2.5 cm in length ×
1.1 cm in greatest diameter. At the distal end of the appendage was a 3-mm
orifice that was patent to probing. Microscopic examination of sections from
the mass (Figure 5 and Figure 6) revealed a hamartomatous malformation
covered by hair-bearing skin. The stromal soft tissues were noted to be composed
of fibroadipose tissue with abundant bundles of skeletal/ muscle. A central
canal was lined by squamous mucosa distally, changing to respiratory-type
mucosa more proximally. Small plates of hyaline cartilage as well as several
normal-appearing peripheral nerves were noted in the soft tissues adjacent
to the central canal.
A, Resected proboscis. B, Whole-mount
section showing fibroadipose stromal soft tissues containing skeletal/ muscle
and surrounding a meandering central canal (hematoxylin-eosin, original magnification).
Transverse cross section of the
proboscis at its base revealing a mucosa-lined central canal with clusters
of submucosal glands and plates of hyaline cartilage (hematoxylin-eosin, original
The mucosal surface varied from
cuboidal/low columnar at the base (A) to hyperplastic variably ciliated pseudostratified
columnar epithelium more distally (B) and to stratified nonkeratinizing squamous
mucosa near the skin surface (hematoxylin-eosin, original magnification ×160).
Proboscis lateralis is a rare congenital anomaly in which a tubular,
nose-like structure is seen to arise from the medial canthal area. Proboscis
lateralis was first mentioned in 1861 by Forster in his monograph Congenital Malformations of the Human Body1
in which he described an 8-month-old girl with a proboscis emanating from
her left frontal area, heminasal aplasia, and a depression between her 2 normal
eyes that was surrounded by eyelids complete with both eyelashes and a conjunctival
lining. Selenkoff, however, is often credited with first describing proboscis
lateralis in an 1884 autopsy.2
Although it was initially reported that no sex predilection existed,3 Boo-Chai2 noted
a 2:1 male-female preponderance. Review of 9 cases subsequent to Boo-Chai's
report supports the notion of a male preponderance with a 3:1 male-female
There does not seem to be any racial predilection in proboscis lateralis.
The embryologic defect that results in proboscis lateralis appears to
involve the nasal placode, which is a primary organizer of the nasal area
of the midface. Duplication of the nasal placode, which is very rare, may
generate a lateral proboscis in the absence of any other facial anomalies.
Usually, however, the nasal placode develops abnormally, which may result
in legion midfacial anomalies, but continues to act on mesenchymal tissue,
allowing it to fuse into the tubular lateral proboscis.
Although the proboscis generally arises from the area of the medial
canthus, exceptionally rare cases have been described in which the anomalous
structure arises from the lateral canthus,4
nasal root,2 chin,10
or is present bilaterally.11 This trunk-like
appendage is generally 2 to 3 cm in length and 1 cm in diameter and has a
central tract lined with respiratory epithelium. The tract drains at a dimpled
opening at the distal end of the proboscis and may be continuous with the
paranasal sinuses proximally. Generally, there is heminasal hypoplasia or
aplasia on the side of the proboscis although, in rare cases, the nose is
normal. Anomalies often affect the nasal cavity as well as the nares, and
complete closure of the nasal cavity at the piriform aperture may be seen
in cases in which heminasal aplasia is present.2
Cleft lip and/or palate may also be present. To the best of our knowledge,
this is the first reported case of proboscis lateralis associated with choanal
Of interest to the ophthalmologist is the frequent association of abnormalities
of the eye and ocular adnexa with proboscis lateralis. Although Wang et al9 reported that ocular defects are rare in patients
with proboscis lateralis, a subsequent review of the literature by Boo-Chai2 noted that 24 of 34 patients with proboscis lateralis
had associated anomalies of the ipsilateral eye and/or ocular adnexa. These
abnormalities included anophthalmia, microphthalmia, microcornea, lenticular
opacities, cyclopean eye, and colobomas of the choroid, retina, iris, and
eyelids. The presence or absence of ocular abnormalities was used by Boo-Chai2 to help categorize patients with proboscis lateralis
into 4 groups: group I has a lateral proboscis with a normal nose (but may
have ocular findings); group II, lateral proboscis with an ipsilateral deformity
of the nose; group III, ipsilateral deformity of the nose and the eye and/or
ocular adnexa; and group IV, cleft lip and/or palate in addition to the nasal
and ocular abnormalities.
It is noteworthy that most patients with proboscis lateralis do not
have serious central nervous system abnormalities, in stark contrast to a
mid-line proboscis, which is often indicative of holoprosencephaly. Nonetheless,
proboscis lateralis may coexist with central nervous system anomalies,4,12 and early neuroimaging is indicated
to rule out intracranial abnormalities.
Because there is some variability in facial anomalies and the degree
of nasal hypoplasia seen with proboscis lateralis, management must be individualized.
When marked hypoplasia or aplasia of the nasal ala is present, reconstruction
is indicated. The structure and texture of the proboscis make it an ideal
substrate for nasal reconstruction, and for this reason, the proboscis should
not be excised if future nasal reconstruction is anticipated. Depending on
the size and location of the proboscis and the degree of nasal hypoplasia,
a variety of techniques may be used to reconstruct an aesthetically acceptable
nare, including use of the proboscis as a pedicle flap.2,3,5- 7,13,14
In our patient, ipsilateral nasal hypoplasia was minimal, and simple
amputation of the proboscis and excision of the fistula connecting it to the
ethmoid sinus was appropriate. However, endoscopic repair of the choanal atresia
was complicated by the narrow nasal opening and required conversion to a transpalatal
approach. At one time, it was suggested that the affected eye be enucleated
to prevent formation of a fistula to the meninges and subsequent meningitis.
There is no evidence, however, that such communication occurs, and enucleation
is not recommended unless tumor is suspected.
Because of the variety of maxillofacial and ocular disease seen with
proboscis lateralis, optimal care of the patient warrants a multidisciplinary
approach that may involve an otolaryngologist or oromaxillofacial surgeon,
plastic surgeon, and ophthalmologist.
This study was supported in part by an unrestricted grant from The Foundation
for Research to Prevent Blindness, New York, NY, and the Alabama Eye Institute,
The authors have no financial interest in the subjects of this article.
Corresponding author and reprints: Martin S. Cogen, MD, Suite 601, 700
18th St S, Birmingham, AL 35233.
Guerrero JM, Cogen MS, Kelly DR, Wiatrak BJ. Proboscis Lateralis. Arch Ophthalmol. 2001;119(7):1071-1074. doi: