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Congenital nasolacrimal duct cysts with nasal obstruction
Congenital nasolacrimal duct cysts with nasal obstruction VICTOR E. CALCATERRA, MD, DONALD J. ANNINO, MD, DMD, BARBARAL. CARTER, MD, and JOHN J. WOOG, MD,
Boston, Massachusetts
A congenital dacryocystocele is a dilatation of the lacrimal sac that occurs within the first few weeks of life as a bluish cystic swelling just below the median canthal area. It is usually accompanied by epiphora and sometimes results in dacryocystitis. Digital massage and antibiotics usually achieves resolution, although probing and dilatation of the nasolacrimal system may be necessary. The cause is thought to be either functional proximal obstruction at the junction of the common canaliculus with the sac or distal nasolacrimal duct obstruction. 1 In 1982 Ratio et al. 2 first reported a case of a congenital dacryocystocele with cystic extension into the nasal cavity. Several reports 1'3-8 have followed that describe this condition in larger numbers of patients. The cystic nasal extension may cause nasal obstruction and possibly respiratory distress. Treatment usually requires intranasal marsupialization of the cyst along with probing and irrigation of the nasolacrimal duct. In 1993 Righi et al. 9 reported a case of bilateral nasolacrimal duct cysts (NLDC) but with no associated congenital dacryocystocele at the medial canthus. Initially, no epiphora or apparent lacrimal sac pathology was found; however, dacryocystitis subsequently occurred and was treated conservatively. Nasal obstruction with respiratory distress was found, for which computerized tomography (CT) and magnetic resonance imaging (MRI) were performed, revealing the presence of bilateral NLDCs. The respiratory distress, which was treated conservatively, resolved. Marsupialization was not per-
From the Departments of Otolaryngology (Drs. Calcaterra and Annino), Radiology (Dr. Carter), and Ophthalmology (Dr. Woog), Tufts University School of Medicine, Boston Floating Hospital for Infants and Children. Received for publication July 7, 1994; accepted March 3, 1995. Reprint requests: Victor E. Calcaterra, MD, Department of Otorhinolaryngology,112 Main St., Wareham, MA 02571. OTOLARYNGOLHEADNECKSURG1995;113:481-4. Copyright © 1995 by the American Academy of OtolaryngologyHead and Neck Surgery Foundation, Inc. 0194-5998/95/$5.00 + 0 23/4/64573
formed. Since this article was written, there has been a report of two more cases of N L D C with no associated congenital dacryocystocele.1° The embryonic development 11of the nasolacrimal drainage system is important to understand. At 6 weeks the lateral nasal process meets the maxillary process at the nasolacrimal groove. These are of ectodermal origin, and the junction is buried as the maxillary mesoderm develops and overgrows it. Between the third and fourth months, the ectodermal cord begins to canalize. It is controversial whether the tract canalizes from a single focus or from multiple sites. However, it is accepted that the last area to open is the most inferior point. This is the area in the inferior meatus of Hasner's valve, the most common point of obstruction. This article presents four more cases of bilateral N L D C with no associated congenital dacryocystocele or lacrimal sac pathology. Two were bilateral, two were unilateral, and all had nasal obstruction. CASE REPORTS
Case I. A patient was referred to the otolaryngology clinic when she was 3.5 weeks old for nasal obstruction and noisy breathing. Her mother reported that the infant required temporary placement of nasal tubes shortly after birth because of respiratory distress. At home, she was feeding adequately and gaining weight. Examination revealed constricted nasal breathing that did not improve after the installation of nose drops. Rigid and flexible fiberoptic examination of her nasal cavities was performed. Choanal atresia or stenosis was not seen; however, there was narrowing in the midnasal passage and bilateral cystic swellings protruding into her inferior turbinates (Fig. 1). There was no epiphora or medial canthal fullness, and an ophthalmologic consultation documented no dilatation of her lacrimal sac or nasolacrimal obstruction. CT of her nasal passages demonstrated bilateral NLDC extending into the inferior meatus and partially obstructing her nasal cavities but no dilatation of the lacrimal sac (Fig. 2). By 3 months, her nasal breathing had improved and was normal. The bilateral NLDC were marsupialized intrana: sally with an endoscopic approach. The lacrimal system 481
482
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Otolaryngology Head and Neck Surgery October t 995
Fig. t. Endoscopic view of the left inferior meatus with extension of the NLDC (C}. T, Inferior turbinate.
was probed and stented with silicone tubing. She was doing well 8 months after the procedure. C a s e 2. A 3-week-old female infant was noted to have mild respiratory distress since birth. She was hospitalized shortly after birth for respiratory difficulty reportedly associated with an upper respiratory infection. She also had mild stridor that was presumed by her pediatrician to be due to laryngomalacia. At the time she was referred to the otolaryngology clinic, the infant was still having nasal obstruction, slight difficulty with feeding, and bilateral epiphora that was possibly greater on the left. Endoscopic nasal examination disclosed a smooth mass protruding into the left inferior meatus, but the right nasal cavity was normal. Fiberoptic examination of her larynx was normal with no laryngomalacia. She had no medial canthal masses. Ophthalmologic examination revealed an elevated tear meniscus bilaterally, mild bilateral mattering of the eyelid that was greater on the left, but no lacrimal sac distention. CT examination documented the presence of a leftsided NLDC displacing the inferior turbinate toward the midline. No lacrimal sac distention was evident. Her nasal obstruction completely resolved after a few months. Because of a possible left nasolacrimal duct obstruction, she underwent endoscopic marsupialization of the left NLDC at 5 months of age. At the beginning of the procedure, the nasolacrimal duct was checked for patency, and dye passed easily from the punctum int O the nose. Endoscopically, dye was seen to flow into the nose posterior to the extension of the NLDC in the inferior meatus. The silicone tubing was removed at 10 months of age, and she has done well thereafter.
Fig. 2. Axial and reconstructed coronal CT images of bilateral NLDC.
In retrospect, it could not be determined whether there was nasolacrimal duct obstruction. Although the findings at initial ophthalmologic examination suggested mild left nasolacrimal duct obstruction, intraoperative testing indicated nasolacrimal duct patency. C a s e 3. Respiratory distress developed at birth in a child delivered by cesarean section at 36 weeks at an outside hospital. A 5F catheter could not be passed through the right nasal cavity but passed with resistance on the left. She was intubated and transferred to the Boston Floating Hospital for Infants and Children at 2 days of age. One day after admission, she was extubated, and her nasal airway was marginal but adequate. Anterior rhinoscopy was unremarkable, and she had no medial canthal mass. CT revealed bilateral NLDC (Fig. 3). Her airway improved over the next few days, and she was transferred back to the referring facility, after which she was lost to follow-up. She returned for a follow-up visit at 18 months of age. Her mother reported that the nasal obstruction had cleared during the first few months of life. Endoscopic examination of her nose revealed bulging in the left inferior meatus, but the right inferior meatus appeared normal. Examination by an ophthalmologic Consultant disclosed no medial canthal mass or evidence of nasolacrimal duct obstruction. Repeat CT showed no significant
Otolaryngology Head and Neck Surgery
Volume 113 Number 4
CALCATERRA et al.
483
Naso,aor,m., ductcyst ~=
-.=
_Inferior turbinate
Fig. 4. Illustration of NLDC with displacement of inferior turbinate.
DISCUSSION
Fig. 3. Axial CT image of bilateral NLDC. Lower panel shows extension into inferior meatus.
change in the bilateral NLDC. No surgery has been performed, and she has been doing well. C a s e 4. A girl was born at 38 weeks gestation by cesarean section to a mother with massive polyhydramnois. In the delivery room, the infant was intubated because of absent spontaneous respirations, and she was transferred to the neonatal intensive care unit at Boston Floating Hospital for Infants and Children. On admission, examination showed a dysmorphic-appearing child weighing 2.8 kg with multiple congenital anomalies. The anomalies included severe congenital heart disease, renal calcifications, prominent cranial ventricles, and severe bilateral optic nerve colobomas. No medial canthal swelling was present. Catheters could not be passed through the nose. CT revealed bony choanal stenosis with membranous atresia and a right NLDC. Also noted on CT were bilateral absent semicircular canals and bilateral large vestibules. The cochleas, middle ears, and ear canals were normal. The multiple anomalies were thought to constitute a CHARGE association. In view of the overwhelming medical problems, the decision was made to terminate life-support systems, and she died at 7 days of age.
Congenital N L D C (Fig. 4) should be considered in all cases of nasal obstruction in the neonate. Whereas the presence of a medial canthal mass suggests that a congenital dacryocystocele with nasal extension may be the cause of neonatal nasal obstruction, the absence of lacrimal sac pathology or mass does not rule out the presence of nasolacrimal duct pathology and compression of the nasal airway. Although case 2 may have had mild nasolacrimal duct obstruction, all four of the case studies presented showed no medial canthal mass or nasolacritual sac disease. Therefore CT or M R I and nasal endoscopy looking for an N L D C should be performed on all neonates with unexplained nasal obstruction. Some authors ~,8report that M R I is superior to CT in imaging the nasolacrimal duct. Therefore M R I is the study of choice when the patient has a congenital dacryocystocele and an associated N L D C is suspected. However, when a neonate has nasal obstruction without a dacryocystocele, a radiographic study is needed that can identify not only an N L D C but also choanal atresia, nasal stenosis, or other nasal pathology. CT with its superior imaging of bone will best provide the information needed. What is the pathologic anatomy of a congenital N L D C ? The only information that is available at this point is that the lower portion of the bony nasolacrimal canal is dilated. There is a cystic protrusion into the inferior meatus at the nasolacrimal ostium, and there is no clinically significant Obstruction in the nasolacrimal duct. It is difficult to reconcile these features, particularly in view of the apparent patency of the nasolacrimal duct. One explanation
484
Otolaryngology Head and Neck Surgery October t 995
CALCATERRA el al.
may be that the cyst is actually a diverticulum of the nasolacrimal duct. Another is that the cyst may be a duplication anomaly of the duct. Finally, there may be partial obstruction at Hasner's valve at the nasolacrimal ostium that causes cystic dilatation but no clinically significant restriction to flow of lacrimal fluid. Further studies need to be done to better define the pathologic a n a t o m y of a congenital NLDC. Initially, we thought that a congenital N L D C was a variant of congenital dacryocystocele with nasal extension. The absence of nasolacrimal duct obstruction, however, suggests that these conditions are fundamentally different. Even though marsupialization was performed in cases 1 and 2, we now believe that surgery may be avoidable. Cases 1 through 3 demonstrate that nasal obstruction will improve slowly over time. Because none of the cases had significant epiphora or dacryocystitis, marsupialization is not required to relieve nasolacrimal impatency. Case 3 demonstrates that an N L D C may not be destined to progressive enlargement with time. However, if the neonate is having significant respiratory distress that interferes with feeding, requires intubation, o r produces uneasiness in the parents despite reassurance, endoscopic marsupialization of the intranasal cyst and placement of silicone stents is appropriate. CONCLUSION
Congenital NLDCs should be considered in any neonate with nasal obstruction, even in the absence of lacrimal sac pathology. Nasal endoscopy and CT or M R I are important in making a diagnosis. Be-
cause the nasal obstruction usually resolves spontaneously and nasolacrimal duct obstruction does not commonly occur, intranasal marsupialization is not usually necessary. The pathologic anatomy of this entity has not been defined a n d warrants further study. REFERENCES
1. Mansour AM, Cheng KP, Mumma JV, et al. Congenital dacryocele. A collaborative review. Ophthalmology1991;98: 1744-51. 2. Ratio GT, Horton JA, Sprinkle PM. An unusual intranasal anomaly of the lacrimal drainage system. Ophthalmic Surg 1982;13:741-4. 3. Devine RD, Anderson RL, Bumsted RM. Bilateral congenital lacrimal sac mucoceleswith nasal extension and drainage. Arch Ophthalmol 1983;101:246-8. 4. Rand PK, Ball WS, Kulwin DR. Congenital nasolacrimal mucoceles: CT evaluation. Radiology1989;173:691-4. 5. John PR, Boldt D. Bilateral congenital lacrimal sac mucoceles with nasal extension. Pediatr Radiol 1990;20:285-6. 6. BerkowitzRG, Grundfast KM, Fitz C. Nasal obstruction of the newborn revisited: clinical and subclinical manifestations of congenital nasolacrimal duct obstruction presenting as a nasal mass. OTOtaRYNOOLHEADNECKSVRO1990;103:468-71. 7. Grin TR, Mertz JS, Stass-Isern M. Congenital nasolacrimal duct cysts in dacryocystocele.Ophthalmology1991;98:123842. 8. Mazzara CA, Respler DS, Jahn AF. Neonatal respiratory distress: sequela of bilateral nasolacrimal duct obstruction. Int J Pediatr Otorhinolaryngol 1993;25:209-16. 9. Righi PD, Hubbell RN, Lawlor PP. Respiratory distress associated with bilateral nasolaerimal duct cysts.Int J Pediatr Otorhinolaryngol 1993;26:199-203. 10. Castillo M, Merten DF, Weissler MC. Bilateral nasolacrimal duct mucocele, a rare cause of respiratory distress: CT findings in two newborns. Am J Neuroradiol 1993;14:1011-3. 11. LangmanJ. Langman'smedical embryology.Baltimore: Williams & Wilkins, 1990.
Boston, Massachusetts
A congenital dacryocystocele is a dilatation of the lacrimal sac that occurs within the first few weeks of life as a bluish cystic swelling just below the median canthal area. It is usually accompanied by epiphora and sometimes results in dacryocystitis. Digital massage and antibiotics usually achieves resolution, although probing and dilatation of the nasolacrimal system may be necessary. The cause is thought to be either functional proximal obstruction at the junction of the common canaliculus with the sac or distal nasolacrimal duct obstruction. 1 In 1982 Ratio et al. 2 first reported a case of a congenital dacryocystocele with cystic extension into the nasal cavity. Several reports 1'3-8 have followed that describe this condition in larger numbers of patients. The cystic nasal extension may cause nasal obstruction and possibly respiratory distress. Treatment usually requires intranasal marsupialization of the cyst along with probing and irrigation of the nasolacrimal duct. In 1993 Righi et al. 9 reported a case of bilateral nasolacrimal duct cysts (NLDC) but with no associated congenital dacryocystocele at the medial canthus. Initially, no epiphora or apparent lacrimal sac pathology was found; however, dacryocystitis subsequently occurred and was treated conservatively. Nasal obstruction with respiratory distress was found, for which computerized tomography (CT) and magnetic resonance imaging (MRI) were performed, revealing the presence of bilateral NLDCs. The respiratory distress, which was treated conservatively, resolved. Marsupialization was not per-
From the Departments of Otolaryngology (Drs. Calcaterra and Annino), Radiology (Dr. Carter), and Ophthalmology (Dr. Woog), Tufts University School of Medicine, Boston Floating Hospital for Infants and Children. Received for publication July 7, 1994; accepted March 3, 1995. Reprint requests: Victor E. Calcaterra, MD, Department of Otorhinolaryngology,112 Main St., Wareham, MA 02571. OTOLARYNGOLHEADNECKSURG1995;113:481-4. Copyright © 1995 by the American Academy of OtolaryngologyHead and Neck Surgery Foundation, Inc. 0194-5998/95/$5.00 + 0 23/4/64573
formed. Since this article was written, there has been a report of two more cases of N L D C with no associated congenital dacryocystocele.1° The embryonic development 11of the nasolacrimal drainage system is important to understand. At 6 weeks the lateral nasal process meets the maxillary process at the nasolacrimal groove. These are of ectodermal origin, and the junction is buried as the maxillary mesoderm develops and overgrows it. Between the third and fourth months, the ectodermal cord begins to canalize. It is controversial whether the tract canalizes from a single focus or from multiple sites. However, it is accepted that the last area to open is the most inferior point. This is the area in the inferior meatus of Hasner's valve, the most common point of obstruction. This article presents four more cases of bilateral N L D C with no associated congenital dacryocystocele or lacrimal sac pathology. Two were bilateral, two were unilateral, and all had nasal obstruction. CASE REPORTS
Case I. A patient was referred to the otolaryngology clinic when she was 3.5 weeks old for nasal obstruction and noisy breathing. Her mother reported that the infant required temporary placement of nasal tubes shortly after birth because of respiratory distress. At home, she was feeding adequately and gaining weight. Examination revealed constricted nasal breathing that did not improve after the installation of nose drops. Rigid and flexible fiberoptic examination of her nasal cavities was performed. Choanal atresia or stenosis was not seen; however, there was narrowing in the midnasal passage and bilateral cystic swellings protruding into her inferior turbinates (Fig. 1). There was no epiphora or medial canthal fullness, and an ophthalmologic consultation documented no dilatation of her lacrimal sac or nasolacrimal obstruction. CT of her nasal passages demonstrated bilateral NLDC extending into the inferior meatus and partially obstructing her nasal cavities but no dilatation of the lacrimal sac (Fig. 2). By 3 months, her nasal breathing had improved and was normal. The bilateral NLDC were marsupialized intrana: sally with an endoscopic approach. The lacrimal system 481
482
CALCATERRA et al.
Otolaryngology Head and Neck Surgery October t 995
Fig. t. Endoscopic view of the left inferior meatus with extension of the NLDC (C}. T, Inferior turbinate.
was probed and stented with silicone tubing. She was doing well 8 months after the procedure. C a s e 2. A 3-week-old female infant was noted to have mild respiratory distress since birth. She was hospitalized shortly after birth for respiratory difficulty reportedly associated with an upper respiratory infection. She also had mild stridor that was presumed by her pediatrician to be due to laryngomalacia. At the time she was referred to the otolaryngology clinic, the infant was still having nasal obstruction, slight difficulty with feeding, and bilateral epiphora that was possibly greater on the left. Endoscopic nasal examination disclosed a smooth mass protruding into the left inferior meatus, but the right nasal cavity was normal. Fiberoptic examination of her larynx was normal with no laryngomalacia. She had no medial canthal masses. Ophthalmologic examination revealed an elevated tear meniscus bilaterally, mild bilateral mattering of the eyelid that was greater on the left, but no lacrimal sac distention. CT examination documented the presence of a leftsided NLDC displacing the inferior turbinate toward the midline. No lacrimal sac distention was evident. Her nasal obstruction completely resolved after a few months. Because of a possible left nasolacrimal duct obstruction, she underwent endoscopic marsupialization of the left NLDC at 5 months of age. At the beginning of the procedure, the nasolacrimal duct was checked for patency, and dye passed easily from the punctum int O the nose. Endoscopically, dye was seen to flow into the nose posterior to the extension of the NLDC in the inferior meatus. The silicone tubing was removed at 10 months of age, and she has done well thereafter.
Fig. 2. Axial and reconstructed coronal CT images of bilateral NLDC.
In retrospect, it could not be determined whether there was nasolacrimal duct obstruction. Although the findings at initial ophthalmologic examination suggested mild left nasolacrimal duct obstruction, intraoperative testing indicated nasolacrimal duct patency. C a s e 3. Respiratory distress developed at birth in a child delivered by cesarean section at 36 weeks at an outside hospital. A 5F catheter could not be passed through the right nasal cavity but passed with resistance on the left. She was intubated and transferred to the Boston Floating Hospital for Infants and Children at 2 days of age. One day after admission, she was extubated, and her nasal airway was marginal but adequate. Anterior rhinoscopy was unremarkable, and she had no medial canthal mass. CT revealed bilateral NLDC (Fig. 3). Her airway improved over the next few days, and she was transferred back to the referring facility, after which she was lost to follow-up. She returned for a follow-up visit at 18 months of age. Her mother reported that the nasal obstruction had cleared during the first few months of life. Endoscopic examination of her nose revealed bulging in the left inferior meatus, but the right inferior meatus appeared normal. Examination by an ophthalmologic Consultant disclosed no medial canthal mass or evidence of nasolacrimal duct obstruction. Repeat CT showed no significant
Otolaryngology Head and Neck Surgery
Volume 113 Number 4
CALCATERRA et al.
483
Naso,aor,m., ductcyst ~=
-.=
_Inferior turbinate
Fig. 4. Illustration of NLDC with displacement of inferior turbinate.
DISCUSSION
Fig. 3. Axial CT image of bilateral NLDC. Lower panel shows extension into inferior meatus.
change in the bilateral NLDC. No surgery has been performed, and she has been doing well. C a s e 4. A girl was born at 38 weeks gestation by cesarean section to a mother with massive polyhydramnois. In the delivery room, the infant was intubated because of absent spontaneous respirations, and she was transferred to the neonatal intensive care unit at Boston Floating Hospital for Infants and Children. On admission, examination showed a dysmorphic-appearing child weighing 2.8 kg with multiple congenital anomalies. The anomalies included severe congenital heart disease, renal calcifications, prominent cranial ventricles, and severe bilateral optic nerve colobomas. No medial canthal swelling was present. Catheters could not be passed through the nose. CT revealed bony choanal stenosis with membranous atresia and a right NLDC. Also noted on CT were bilateral absent semicircular canals and bilateral large vestibules. The cochleas, middle ears, and ear canals were normal. The multiple anomalies were thought to constitute a CHARGE association. In view of the overwhelming medical problems, the decision was made to terminate life-support systems, and she died at 7 days of age.
Congenital N L D C (Fig. 4) should be considered in all cases of nasal obstruction in the neonate. Whereas the presence of a medial canthal mass suggests that a congenital dacryocystocele with nasal extension may be the cause of neonatal nasal obstruction, the absence of lacrimal sac pathology or mass does not rule out the presence of nasolacrimal duct pathology and compression of the nasal airway. Although case 2 may have had mild nasolacrimal duct obstruction, all four of the case studies presented showed no medial canthal mass or nasolacritual sac disease. Therefore CT or M R I and nasal endoscopy looking for an N L D C should be performed on all neonates with unexplained nasal obstruction. Some authors ~,8report that M R I is superior to CT in imaging the nasolacrimal duct. Therefore M R I is the study of choice when the patient has a congenital dacryocystocele and an associated N L D C is suspected. However, when a neonate has nasal obstruction without a dacryocystocele, a radiographic study is needed that can identify not only an N L D C but also choanal atresia, nasal stenosis, or other nasal pathology. CT with its superior imaging of bone will best provide the information needed. What is the pathologic anatomy of a congenital N L D C ? The only information that is available at this point is that the lower portion of the bony nasolacrimal canal is dilated. There is a cystic protrusion into the inferior meatus at the nasolacrimal ostium, and there is no clinically significant Obstruction in the nasolacrimal duct. It is difficult to reconcile these features, particularly in view of the apparent patency of the nasolacrimal duct. One explanation
484
Otolaryngology Head and Neck Surgery October t 995
CALCATERRA el al.
may be that the cyst is actually a diverticulum of the nasolacrimal duct. Another is that the cyst may be a duplication anomaly of the duct. Finally, there may be partial obstruction at Hasner's valve at the nasolacrimal ostium that causes cystic dilatation but no clinically significant restriction to flow of lacrimal fluid. Further studies need to be done to better define the pathologic a n a t o m y of a congenital NLDC. Initially, we thought that a congenital N L D C was a variant of congenital dacryocystocele with nasal extension. The absence of nasolacrimal duct obstruction, however, suggests that these conditions are fundamentally different. Even though marsupialization was performed in cases 1 and 2, we now believe that surgery may be avoidable. Cases 1 through 3 demonstrate that nasal obstruction will improve slowly over time. Because none of the cases had significant epiphora or dacryocystitis, marsupialization is not required to relieve nasolacrimal impatency. Case 3 demonstrates that an N L D C may not be destined to progressive enlargement with time. However, if the neonate is having significant respiratory distress that interferes with feeding, requires intubation, o r produces uneasiness in the parents despite reassurance, endoscopic marsupialization of the intranasal cyst and placement of silicone stents is appropriate. CONCLUSION
Congenital NLDCs should be considered in any neonate with nasal obstruction, even in the absence of lacrimal sac pathology. Nasal endoscopy and CT or M R I are important in making a diagnosis. Be-
cause the nasal obstruction usually resolves spontaneously and nasolacrimal duct obstruction does not commonly occur, intranasal marsupialization is not usually necessary. The pathologic anatomy of this entity has not been defined a n d warrants further study. REFERENCES
1. Mansour AM, Cheng KP, Mumma JV, et al. Congenital dacryocele. A collaborative review. Ophthalmology1991;98: 1744-51. 2. Ratio GT, Horton JA, Sprinkle PM. An unusual intranasal anomaly of the lacrimal drainage system. Ophthalmic Surg 1982;13:741-4. 3. Devine RD, Anderson RL, Bumsted RM. Bilateral congenital lacrimal sac mucoceleswith nasal extension and drainage. Arch Ophthalmol 1983;101:246-8. 4. Rand PK, Ball WS, Kulwin DR. Congenital nasolacrimal mucoceles: CT evaluation. Radiology1989;173:691-4. 5. John PR, Boldt D. Bilateral congenital lacrimal sac mucoceles with nasal extension. Pediatr Radiol 1990;20:285-6. 6. BerkowitzRG, Grundfast KM, Fitz C. Nasal obstruction of the newborn revisited: clinical and subclinical manifestations of congenital nasolacrimal duct obstruction presenting as a nasal mass. OTOtaRYNOOLHEADNECKSVRO1990;103:468-71. 7. Grin TR, Mertz JS, Stass-Isern M. Congenital nasolacrimal duct cysts in dacryocystocele.Ophthalmology1991;98:123842. 8. Mazzara CA, Respler DS, Jahn AF. Neonatal respiratory distress: sequela of bilateral nasolacrimal duct obstruction. Int J Pediatr Otorhinolaryngol 1993;25:209-16. 9. Righi PD, Hubbell RN, Lawlor PP. Respiratory distress associated with bilateral nasolaerimal duct cysts.Int J Pediatr Otorhinolaryngol 1993;26:199-203. 10. Castillo M, Merten DF, Weissler MC. Bilateral nasolacrimal duct mucocele, a rare cause of respiratory distress: CT findings in two newborns. Am J Neuroradiol 1993;14:1011-3. 11. LangmanJ. Langman'smedical embryology.Baltimore: Williams & Wilkins, 1990.