CASE 8868 Published on 26.10.2010

Congenital nasal piriform aperture stenosis

Section

Head & neck imaging

Case Type

Clinical Cases

Authors

Alves N, Sousa M, Carneiro A, Pina S, Moreira B.

Patient

1 days, male

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Clinical History

One-day-old male patient, born by caesarean after 40 weeks gestation.
Nasal obstruction was noted on the first hours. Later the patient presented with an episode of de-saturation with stridor and signs of breathing difficulty, requiring oxygen. Pulmonary auscultation and thoracic fluoroscopy were normal. An attempt to permeate the nostrils with a catheter failed.

Imaging Findings

A Computed Tomography (CT) was performed to evaluate the upper airways.
Unenhanced CT showed a reduction of the piriform apertures due to bilateral overgrowth of the nasal processes of the maxillae, free nasal choanae and normal appearance of the pharynx.

Discussion

Infants are preferably nasal breathers until 6 to 8 weeks, and any cause of nasal obstruction can result in respiratory distress [1, 2].

The differential diagnosis of nasal obstruction includes choanal atresia, congenital nasal piriform aperture stenosis (CNAPS), nasopharyngeal cephalocele, and congenital nasal tumours [3, 4]. Choanal atresia is the most common cause, while CNPAS is an uncommon cause of congenital airways obstruction [5]. In choanal atresia a bone and/or membranous plate obstructs the posterior nasal cavity. In CNPAS the anterior nasal cavity is narrowed but patent.

The nasal piriform aperture is a pear shaped opening bounded by the nasal bone superiorly, nasal process of the maxilla laterally, and palatine process inferiorly.

CNPAS was described in 1988 by Ey [1] and in 1989 by Brown [6]. The finding of piriform aperture stenosis had been described in adults in 1952 [7].

CNPAS usually presents at birth with cyclic cyanosis, breathing difficulty (particularly when breastfeeding), and nasal cavity narrowing that renders impossible placing a nasogastric tube. Less commonly, it presents later in life with the onset of an upper respiratory infection.
Typical imaging findings of CNPAS include narrowed bone inlet, triangular shaped palate, bone overgrowth in the nasal process of the maxilla, and abnormal dentition, namely a megaincisor [1, 3, 6, 8, 9].

There are reports of several anomalies associated with CNPAS such as forms of holoprosencephaly [9, 10], facial haemangiomas, clinodactyly, pituitary dysfunction, anomalies of the vestibular system [11] and, in 75% of cases, a central megaincisor [12].

CT is the best modality for evaluation of congenital airways breathing obstruction.
Diagnosis of bony inlet stenosis can be made accurately by obtaining thin axial sections in a plane parallel to the hard palate. Direct coronal imaging is useful, although the diagnosis can be made with measurement of the piriform stenosis on transverse CT findings [1, 8, 13].
A piriform aperture width of less than 11 mm measured at the level of the inferior meatus, between the medial aspects of the nasal processes of the maxillae, is diagnostic of congenital piriform aperture stenosis [13]. Measurement of CNPAS with 3D-CT can be useful to evaluate the width in different parts of the piriform aperture pre- and postoperatively [14]. CT also allows exclusion of other causes of airways obstruction, particularly showing free posterior nasal choanae, and details the underlying anatomical abnormality, assisting in surgical planning.

MR imaging may also be required to adequately evaluate the brain and soft-tissue components of midface anomalies, especially congenital masses and craniofacial syndromes [12].

Patients with CNPAS have very good prognosis. The mild cases are treated conservatively, with topical nasal decongestants and humidification. Severe cases can benefit from surgical enlargement of the nasal opening through an upper buccal sulcus [6, 15, 16].

Differential Diagnosis List

Congenital nasal piriform aperture stenosis.

Final Diagnosis

Congenital nasal piriform aperture stenosis.

References

[1] Ey EH, Han BK, Towbin RB, Jaun WK. (1988) Bony inlet stenosis as a cause of nasal airway obstruction. Radiology 477—479 (PMID: 3393667)

[2] Abbeele T.V.D., Triglia J.M., Francois M., Narcy P. (2001) Congenital nasal pyriform Aperture stenosis: diagnosis and management of 20 cases. Ann. Otol. Rhinol. Laryngol 110(1):70-5 (PMID: 11201813)

[3] Knegt-Junk KJ, Bos CE, Berkovits RNP. (1988) Congenital nasal stenosis in neonates. J Laryngol Otol 102:500–502. (PMID: 3397648)

[4] Som PM, Curtin HD. (2003) Pediatric airway disease: Congenital airway diseases. Head and neck imaging. 4th ed. St Louis, Mosby Vol. 2. pp:1538-1543

[5] Lowe LH, Booth TN, Joglar JM, Rollins NK. (2000) Midface anomalies in children. Radiographics 20(4):907-22 (PMID: 10903683)

[6] Brown OE, Myer CM, Manning SC. (1989) Congenital nasal pyriform aperture stenosis. Laryngoscope 99(1):86-91. (PMID: 2909825)

[7] B. Douglas (1952) The relief of vestibular nasal obstruction by partial resection of the nasal process of the superior maxilla. Plas Reconstr Surg 9(1):42-51. (PMID: 14891404)

[8] Bignault A, Castillo M. (1994) Congenital nasal piriform aperture stenosis. AJNR 15:877–878. (PMID: 8059654)

[9] Arlis H, Ward RF. (1992) Congenital nasal pyriform aperture stenosis: isolated abnormality vs developmental field defect. Arch Otolaryngol Head Neck Surg 118: 989–991. (PMID: 1503729)

[10] Krol BJ, Hulka GF, Drake A. (1998) Congenital nasal pyriform aperture stenosis in the monozygotic twin of a child with holoprosencephaly. Otolaryngol Head Neck Surg 118(5):679-81. (PMID: 9591870)

[11] Rajaram S, Bateman N, Raghavan A. (2008) Congenital nasal piriform aperture stenosis with vestibular abnormality. Pediatr Radiol 38(10):1128-9. Epub 2008 Jul 8. (PMID: 18607583)

[12] Castillo M. (1994) Congenital abnormalities of the nose: CT and MR findings. AJR Am J Roentgenol 162:1211–1217 (PMID: 8166012)

[13] Belden CJ, Mancusso AA, Schmalfuss IM. (1999) CT features of congenital nasal piriform aperture stenosis: initial experience. Radiology 213:495–501 (PMID: 10551232)

[14] Lee JC, Yang CC, Lee KS, Chen YC. (2006) The measurement of congenital nasal pyriform aperture stenosis in infant. Int J Pediatr Otorhinolaryngol 70(7):1263-7. (PMID: 16540178)

[15] Losken A, Burstein FD, Williams JK. (2002) Congenital nasal pyriform aperture stenosis: diagnosis and treatment. Plast Reconstr Surg 109(5):1506-11 (PMID: 11932589)

[16] Burstein FD, Cohen SR. (1995) Piriform aperture stenosis: a rare cause of neonatal airway obstruction. Ann Plast Surg 34: 56-8. (PMID: 7702302)

Case information

URL:	https://www.eurorad.org/case/8868
DOI:	10.1594/EURORAD/CASE.8868
ISSN:	1563-4086

Figure 1

Unenhanced computed tomography

Sagittal plane. No obstacles are apparent in the upper airways, namely in the choanae.

Coronal plane. No airways obstruction can be seen at the level of the choanae.

Axial plane. There is a narrowing of the piriform apertures due to bilateral overgrowth of the nasal processes of the maxillae. No obstacles can be seen, namely in the choanae.