The management of midline transcranial nasal dermoid sinus cysts *

Transcription

1 British Journal of Plastic Surgery (2005) 58, The management of midline transcranial nasal dermoid sinus cysts * M. Hanikeri*, N. Waterhouse, N. Kirkpatrick, D. Peterson, I. Macleod Department of Craniofacial Surgery, Chelsea and Westminster Hospital, 369 Fulham Road, Chelsea, London SW10 9NH, UK Received 23 September 2004; accepted 24 May 2005 KEYWORDS Midline nasal dermoid; Transcranial; Craniofacial approach; Skull base; Open rhinoplasty approach Summary The most common congenital midline nasal masses are nasal dermoid sinus cysts (NDSC) [Hughes GB, Sharpino G, Hunt W, Tucker HM. Management of the congenital midline nasal mass a review. Head Neck Surg 1980;2: ]. Their clinical importance hinges on their potential to communicate with the central nervous system. Preoperative diagnosis of an intracranial extension allows for referral to a craniofacial team with the appropriate skills and experience for a transcranial approach. All patients with a NDSC require imaging with high resolution multiplanar MRI scans and complimentary fine cut CT scan to reveal the anatomical extent of the tract and its relationship to the anterior cranial fossa. A single-stage craniofacial approach to resection of midline NDSC extending to the anterior cranial base is effective with minimal morbidity [Yavuzer R, Bier U, Jackson IT. Be careful: it might be a nasal dermoid cyst. Plast Reconstr Surg 1999;103:2082 3; Denoyelle F, Ducroz V, Roger G, Garabedian EN. Nasal dermoid sinus cysts in children. Laryngoscope 1997;107: ; Rohrich RJ, Lowe JB, Schwartz MR. The role of open rhinoplasty in the management of nasal dermoid cysts. Plast Reconstr Surg 1999;104: ; Rahbar R, Shah P, Mulliken JB, et al. The presentation and management of nasal dermoid a 30-year experience. Arch Otolaryngol Head Neck Surg 2003;129:464 71; Posnick JC, Bortoluzzi P, Armstrong DC, Drake JM. Intracranial nasal dermoid sinus cysts: computed tomographic scan findings and surgical results. Plast Reconstr Surg 1994;93: [discussion ]; Bartlett SP, Lin KY, Grossman R, Kratowitz J. The surgical management of orbitofacial dermoids in the pediatric patient. Plast Reconstr Surg 1993;91: ,3,7,9,11,18 ]. The cyst and tract are accessed through a combination of a nasal and transcranial approach. This allows visualisation and dissection of the tract with only a small incision on the nasal dorsum to include the cutaneous punctum when present. Transnasal endoscopic techniques have been advocated where the dermoid is located within the nasal cavity and there is little or no cutaneous involvement [Weiss DD, Robson CD, Mulliken JB. Transnasal endoscopic excision of midline nasal dermoid from the anterior cranial base. Plast Reconstr Surg 1998;101: ]. * Presented at the European Society of Craniofacial Surgery annual meeting, Geneva, Switzerland, September * Corresponding author. Address: 38 Marlow Street, Wembley, WA, Australia. Tel./fax: C address: hanikeri@mac.com (M. Hanikeri). S /$ - see front matter q 2005 The British Association of Plastic Surgeons. Published by Elsevier Ltd. All rights reserved. doi: /j.bjps

2 1044 M. Hanikeri et al. We present a review of five cases referred to our unit between 1999 and 2004 with a diagnosis of a midline nasal dermoid sinus cyst and radiological evidence of intracranial communication. All cases had a communication with the anterior cranial fossa diagnosed preoperatively and were treated surgically with a craniofacial approach. An intracranial extension was identified at operation in each case and this was confirmed on histopathology. The only significant complication resulted from an early postoperative infection, requiring re-operation. There were no recurrences and acceptable aesthetic outcomes have been observed in all cases. q 2005 The British Association of Plastic Surgeons. Published by Elsevier Ltd. All rights reserved. The differential diagnosis of a midline nasal mass includes inflammatory lesions, post-traumatic deformities, benign and malignant neoplasms, developmental masses and vascular malformations. Developmental midline nasal masses include nasal dermoids, nasal gliomas and encephaloceles. These are relatively rare congenital anomalies, estimated to occur in 1: births. 1 3 Nasal dermoid cysts constitute 1 3% of all dermoids and % of dermoids in the head and neck. 1 7 They are commonest midline congenital nasal lesion 3 accounting for 61% of midline nasal masses in children. 7 Unlike epidermoid or sebaceous cysts, which are purely ectodermal, dermoid cysts contain both ectodermal and mesodermal elements, including adnexal structures and sebaceous glands. 1,7 9 In contrast to teratomas, they contain no endodermally derived structures. 9 Midline NDSC may present as a nasal mass, pit or fistula located anywhere from the glabella to columella. Although the majority of lesions are superficial with no deep extension, a variably reported percentage may end blindly within the deeper midline structures of the nose or extend intracranially Hair protruding from the punctum is pathognomonic of dermoid cysts. 8 Rarely, multiple ostia are present and midline cysts may exist at more than one level on the nose and glabella. 4,6 They may secrete sebaceous material and can become intermittently inflamed or infected. Sequelae of infection can result in osteomyelitis, meningitis or cerebral abscess. These complications may result from inadequate surgical excision. 2 craniotomy, along with an incision on the nose where required to excise the punctum. Lesions where a punctum was located over the nasal dorsum or glabella were excised with a vertical skin ellipse encompassing the punctum. Lesions involving the tip/lobular complex were excised through an open rhinoplasty approach. An intracranial extension was identified at operation in each case and this was confirmed on histopathology. The only significant complication resulted from an early postoperative infection, requiring re-operation. Case 1 A 6-year-old boy presented to the emergency department with an acute cutaneous abscess in the right paranasal area. A midline punctum was noted on the dorsum of his nose (Fig. 1). MRI scan revealed a NDSC extending to the dura. This was excised via a trancranial approach including the infected communication with the skin at the medial canthus. His initial postoperative recovery was uneventful but on the fifth postoperative day, the patient represented to the emergency department, acutely unwell with signs of sepsis and a purulent discharge from the original paranasal abscess site. Patients and methods This study reviews five cases referred to our unit with a diagnosis of a NDSC with intracranial communication between 1999 and All cases were treated surgically with a craniofacial approach utilising a bicoronal incision and frontal Figure 1 Case 1. Note the abscess in the right medial canthal region and the midline punctum on the nasal dorsum.

3 The management of midline transcranial nasal dermoid sinus cysts 1045 Immediate re-operation and re-exploration of the surgical field demonstrated infected pericranial flaps and pus in the anterior cranial fossa. Debridement of all necrotic tissue and aggressive antibacterial therapy resulted in a rapid recovery and uneventful healing. Case 2 A 4-year-old girl was referred from overseas for management of a nasal dermoid with multiple episodes of acute infection and orbitofacial cellulitis. A punctum was noted in the nasal supratip area. She exhibited moderate developmental delay and dysmorphic facial features including frontal bossing, low-set ears and mild hypertelorism. Parental consanguinity was noted. Her younger sister also had a NDSC, with no intracranial extension. An MRI revealed a NDSC with a tract extending to the dura. At operation the tract was seen to extend along the falx between the frontal lobes for 4 cm. Resection required excision of a segment of dura and reconstruction with a pericranial dural patch. Case 3 A 5-year-old boy was referred from another unit for management of a NDSC with a transcranial extension revealed by MRI. A punctum with protruding hair was located in the midline between the glabella and the nasal tip. The dermoid, its tract and a cuff of attached dura were excised through a craniofacial approach. The dural defect was repaired primarily. Case 4 A 56-year-old man was referred with a midline punctum on the tip of his nose associated with an occasional discharge of cheesy material and localised infections of the surrounding skin 2 3 times a year. A small central keratinaceous plug and tufts of hair were visible within the punctum. MRI scan confirmed a 5 cm midline NDSC with a tract traversing the skull base in the region of the cribriform plate and extending to the dura at the falx. A craniofacial approach was employed to remove the cyst and tract, which passed between the olfactory sleeves to blend with the dura in the midline over a length of several centimetres (Fig. 2). The nasal bones and frontal bone plate were removed en bloc, to improve exposure of the tract. A small segment Figure 2 Lesion in case 4. Note the insertion of the cyst tract into the dura in the midline. of dura was excised with the lesion and the dural defect was repaired. Case 5 A 12-year-old girl was referred having been previously treated with a local excision of a NDSC. Persistent discharge and hair growth through the nasal scar prompted an MRI scan (Fig. 3). This demonstrated a sinus tract extending to the anterior cranial fossa, whilst CT scan confirmed a bifid nasal septum with a prominent notch at the caudal edge of the nasal bones. A craniofacial approach employing an en bloc fronto-nasal bone flap was used to gain exposure to the sinus tract. The tract extended from the nasal scar, through the caudal edge of the nasal bones, bifid septum and base of skull, to blend with the dura at the level of the cribriform plates (Fig. 4). Figure 3 Case 5. Note the hair protruding through the midline punctum.

4 1046 Figure 4 Lesion in case 5 showing tract extending through nasal bones in midline. Discussion Aetiology and pathogenesis Three main theories have emerged in the literature to account for the development of midline NDSC. Of these, the prenasal theory based on observations by Grunwald in 1910 and refined by Pratt in 1965 has gained the widest support. 7 At about 8 weeks of gestation, a dural diverticulum protrudes through the fonticulus nasofrontalis, between the paired nasal and frontal bones and inferiorly into the prenasal space, which is located between the nasal bones and the nasal capsule. The nasal capsule is a cartilage block in the developing anterior skull base, which develops into the septum, perpendicular plate of ethmoid and the crista galli. As the nasal processes of the frontal bones grow, they surround the diverticulum to form the foramen caecum and thereby separate the dura from the skin. 1,6 This diverticulum normally involutes and as it does so, the foramen caecum is filled with fibrous tissue. After obliteration of the neurectodermal connection, the fonticulus nasofrontalis and foramen caecum fuse and the cribriform plates form. 9 A failure of the process results in incomplete closure of the midline along the path of the diverticulum. 1,10 It is thought that if the dura remains attached to the dermis, as the dura recedes from the prenasal space, it may pull nasal ectoderm upwards and inwards which results in trapped cutaneous elements along the path of the diverticulum. 1,10 Proliferation of entrapped M. Hanikeri et al. epithelium produces a dermoid, which exists as an epithelial-lined sac containing adnexal structures including glands and hair follicles. In most cases, a sinus tract connects the cyst to the skin surface in the midline between the glabella and columella. If brain tissue is isolated extracranially, a glioma results. If a bony defect persists and allows herniation of dura and brain tissue, an encephalocoele results. 6 Though there are no syndromes associated with the development of NDSC, congenital anomalies have been reported in association with these lesions in up to 41% of cases. 8 These include other craniofacial abnormalities such as hypertelorism, cleft lip and palate, hemifacial microsomia and aural atresia, as well as defects including hydrocephalus, branchial sinuses, albinism, cardiac, gastrointestinal, genital and CNS anomalies. 3,4,8,9,11,12 One of the cases in this series (case 2) had dysmorphic craniofacial features and developmental delay. The same patient also had a sibling who had a superficial midline nasal dermoid. The parents of these siblings were consanguineous. Although there is no proven genetic basis for the development of nasal dermoids, there are several reports in the literature of these lesions clustering within families 4,13 16 and an autosomal dominant inheritance in some instances has been proposed. 15 A case of identical triplets all of whom had NDSC located at different positions on the nose has also been reported. 8 These cases imply that a genetic basis for the development of these lesions may exist. There is some disagreement about the frequency of intracranial extension in NDSC. Most series have reported rates of intracranial extension of dermoids between 4 and 57%. Bradley noted that involvement of the nasal bones, septum or cribriform plate occurred in 23 of 67 cases (34.3%). Transcranial extension occurred in seven of these cases (10.4%). 13 Wardinski showed that in patients with other anomalies the frequency of intracranial extension rose to 65% compared to 31% in which the NDSC was an isolated finding. 8 A meta-analysis of multiple series results in a frequency of intracranial extension for NDSC of 19.6% 3,4,6,8,9,11,13,17,18 (Table 1). Nevertheless, all patients with a midline NDSC should be considered to have an intracranial extension until proven otherwise. 3 Most NDSC with intracranial extension are extradural, limited to the anterior cranial fossa and adherent to the dura or confined within the leaves of the falx cerebri. 8,19 Rarely, intracerebral cases have been reported with associated symptoms of central nervous system involvement. 19

5 The management of midline transcranial nasal dermoid sinus cysts 1047 Table 1 Analysis of frequency of intracranial extension from several series Series Number of cases in series Number of cases with intracranial extension Denoyelle et al Sessions Pensler et al Wardinsky et al Rahbar et al Posnick et al Bradley et al Bloom et al Bartlett et al Total Frequency of intracranial extension (%) Diagnosis and assessment Whilst the majority of NDSC are diagnosed in infancy and childhood, there are several reports of diagnosis later in life. 2 4,6,7,9,11,19,20 NDSC can be differentiated clinically from encephalocoeles by their lack of transillumination and failure to enlarge with crying (Valsalva s manouvre) or with compression of the ipsilateral internal jugular vein (Fursteinberg sign). Whilst nasal gliomas may cause hypertelorism and are sometimes associated with obstruction of the nasal passages or nasolacrimal apparatus with resultant epiphora, these signs have not been associated with nasal dermoids. Imaging with CT or MRI scanning is mandatory for all midline nasal lesions. These will usually distinguish a NDSC from other midline developmental masses. Radiological findings may include a soft tissue mass with or without intracranial extension, fluid filled cyst, enlargement of the foramen caecum, distortion or bifidity of the crista galli and defects in the cribriform plate. 3,6,9,17,21 CT scans are useful for delineating bony abnormalities suggestive of intracranial involvement. These signs are indirect evidence of intracranial extension and are not diagnostic, however, their absence indicates that an intracranial connection is unlikely. 6 In children, before the age of one, there may not be ossification of the crista galli and perpendicular plate of the ethmoid. This may impair the interpretation of CT scans in this group. 3,6,11 MRI provides higher resolution of soft tissues and may show direct and indirect evidence of intracranial extension Some studies have demonstrated a higher sensitivity of MRI, compared with CT scanning for detection of intracranial extension of these lesions as well as detection of other intracranial abnormalities. 3,17 This, combined with the increased cost of two tests, potential for delay in diagnosis and added risk of additional anaesthesia and exposure to ionising radiation with CT scanning, favours MRI as the initial imaging study. 3,17,21 The high fat content of NDSC, renders them hyper-intense on T1 weighted images. 21,22 It is important to distinguish this from the intraosseous fat deposition that occurs with normal maturation and during aeration of the frontal sinuses. 23 Computed tomography and MRI may provide complementary information and are, therefore, often both performed to delineate bony and soft-tissue characteristics. 23 Surgical treatment Early treatment with complete excision of the entire lesion along with any fistulous tract is recommended in order to prevent recurrence and to avoid distortion of the nose or disruption of growth caused by recurrent inflammation or infections. Failure to completely excise the cyst and tract may result in abscess formation, osteomyelitis or meningitis if the lesion has an intracranial component. 2,24 There are no studies, which compare the results of a one-stage with a two-stage procedure (transcutaneous excision of the cyst followed by transcranial excision of the tract). The effectiveness of complete removal of the lesion en bloc, without any reports of increased morbidity associated with this approach would favour a one-stage procedure for surgical management of midline NDSC. 1 3,5 9,17,18,23 29 Since, most of these lesions are excised in childhood, this is best performed in the context of a specialised paediatric craniofacial unit. There is controversy as to whether the presence of an intracranial connection, without an intracranial mass, dictates the need for a combined craniofacial approach. It has been suggested that

6 1048 the tract from intracranial extension of a NDSC is often fibrous and does not need formal excision. 4 If frozen section analysis of the tract before it enters the skull base demonstrates fibrous tissue only, with no evidence of an epithelial tract, some have suggested that the residual tract can be ligated without the need for formal excision through a transcranial approach. 3,4,6,18 In contrast, Posnick et al. have proposed that epidermal and adnexal structures may be scattered throughout the tract at presentation and that a negative biopsy may, therefore, give a false impression that no dermal components exist more proximally. They, therefore, recommend complete excision of the NDSC and tract through a transcranial approach whenever an intracranial connection is identified. 11 The ideal surgical approach to midline NDSC with intracranial extension should fulfil four criteria: (1) provide excellent access to a midline cyst; (2) allow access to the base of skull; (3) provide adequate exposure for reconstruction of the nasal dorsum; (4) result in an acceptable scar. 25 Endoscopic techniques for excision of NDSC have been reported when there is little or no cutaneous involvement. 26 The technique may be combined with a frontal craniotomy for neurosurgical exposure, where the NDSC extends to the leaves of the falx cerebri. 26 A number of open approaches, including transverse, vertical, lateral rhinotomy, inverted-u and open rhinoplasty, have been proposed. 2 6,25 An open rhinoplasty approach with a stair-step columellar incision has been recommended by several authors as it allows wide exposure of the nasal dorsum, controlled external osteotomies, ease of dorsal reconstruction and ease of exposure of the upper lateral cartilages and septum with an improved aesthetic result. 7,27,28 Our preference is to use a combination of a vertical incision incorporating the punctum and when necessary, especially for lesions affecting the tip and supratip area, we combine this with an open rhinoplasty incision. We use a stealth bicoronal incision for exposure for the frontal craniotomy. A neurosurgeon is routinely involved with all transcranial cases in our department. The cyst with its punctum and fibrous tract are excised en mass. If necessary, the tract can be cannulated with a lacrimal probe to help define the extracranial path. Nasal osteotomies with separation of the nasal bones at the level of the nasofrontal suture may improve the exposure and to access the sinus tract in the anterior cranial fossa as well as the nasal septum. 9 Complete visualisation of the tract was achieved in the last two patients in M. Hanikeri et al. Figure 5 (a) and (b) Modified en bloc frontonasal bone flap improves exposure to nasal septum and anterior cranial fossa. Note bifidity of the crista galli in 7B. our series through elevation of a modified en bloc fronto-nasal bone flap (Fig. 5(a) and (b)). Frequently, excision of the NDSC and its tract requires excision of a segment of involved dura. The frontal bone flaps are replaced, after cranialisation of the frontal sinuses if present. We use a pericranial flap to line the intracranial defect

7 The management of midline transcranial nasal dermoid sinus cysts 1049 between the floor of the anterior cranial fossa and the dura, thereby separating the intracranial structures from the frontonasal ducts. We use a second pericranial flap to lie over the craniotomy site. The recurrence rate for lesions treated with a combined approach is unknown, though rates of % have been reported if dermal remnants remain postoperatively. 29 One study showed a recurrence in two of 32 patients treated through an external rhinoplasty approach. 3 There has been no recurrence observed in this series with a mean follow-up of 2 years (range 0 5 years). Midline NDSC are an uncommon developmental anomaly. All patients presenting with a midline nasal mass require imaging with MRI and CT scan to exclude a transcranial extension which may exist in 20% of cases (Fig. 6). When identified, a transcranial lesion requires early, complete excision, which is best performed as a single stage adopting a craniofacial approach. This is most appropriately performed by a paediatric craniofacial team. Lesions with intracranial extension may be excised through a transcranial approach through a bicoronal incision combined with an open rhinoplasty approach and a vertical ellipse incorporating the punctum. This provides good exposure of midline Figure 6 Open rhinoplast approach to lesion in case 4. Good visualisation of the tract through a bifid nasal septum is achieved. lesions, the septum and skull base. It also improves the access for reconstruction if required whilst leaving minimal scarring. References 1. Hughes GB, Sharpino G, Hunt W, Tucker HM. Management of the congenital midline nasal mass a review. Head Neck Surg 1980;2: Yavuzer R, Bier U, Jackson IT. Be careful: it might be a nasal dermoid cyst. Plast Reconstr Surg 1999;103: Denoyelle F, Ducroz V, Roger G, Garabedian EN. Nasal dermoid sinus cysts in children. Laryngoscope 1997;107: Sessions RB. Nasal dermal sinuses: new concepts and explanations. Laryngoscope 1982;92(Pt2, Suppl 29): Kelly JH, Strome M, Hall B. Surgical update on nasal dermoids. Arch Otolarygol 1982;108: Pensler J, Bauer B, Naidich T. Craniofacial dermoids. Plast Reconstr Surg 1988;82: Rohrich RJ, Lowe JB, Schwartz MR. The role of open rhinoplasty in the management of nasal dermoid cysts. Plast Reconstr Surg 1999;104: Wardinsky TD, Pagon RA, Kropp RJ, Hayden PW, Clarren SK. Nasal dermoid sinus cysts: association with intracranial extension and multiple malformations. Cleft Palate Craniofac J 1991;28: Rahbar R, Shah P, Mulliken JB, Robson CD, Perez-Atayde AR, Proctor MR, et al. The presentation and management of nasal dermoid a 30-year experience. Arch Otolaryngol Head Neck Surg 2003;129: Pratt LW. Midline cysts of the nasal dorsum: embryologic origin and treatment. Laryngoscope 1965;75: Posnick JC, Bortoluzzi P, Armstrong DC, Drake JM. Intracranial nasal dermoid sinus cysts: computed tomographic scan findings and surgical results. Plast Reconstr Surg 1994;93: [discussion ]. 12. Morgan DW, Evans JNG. Developmental nasal anomalies. J Laryngol Otol 1990;104: Bradley PJ. Nasal dermoids in children. Int J Pediatr Otorhinolaryngol 1981;3: Muhlbauer WD, Dittmar W. Hereditary median dermoid cyst of the nose. Br J Plast Surg 1976;29: Bratton C, Suskind DL, Thomas T, Kluka EA. Autosomal dominant familial frontonasal dermoid cysts: a mother and her identical twin daughters. Int J Pediatr Otorhinolaryngol 2001;57: Anderson PJ, Dobson C, Berry RB. Nasal dermoid cysts in siblings. Ir J Med Sci 1997;166: Bloom DC, Carvalho DS, Dory C, Brewster DF, Wickersham JK, Kearns DB. Imaging and surgical approach of nasal dermoids. Int J Pediatr Otorhinolaryngol 2002;62: Bartlett SP, Lin KY, Grossman R, Kratowitz J. The surgical management of orbitofacial dermoids in the pediatric patient. Plast Reconstr Surg 1993;91: Uglietta JP, Boyko OB, Rippe DJ, Fuller GN, Schiff SJ, Heinz ER. Intracerebral extension of nasal dermoid cyst: CT appearance. J Comput Assist Tomogr 1989;13: Hacker DC, Freeman JL. Intracranial extension of a nasal dermoid sinus cyst in a 56-year-old man. Head Neck 1994;16: Huisman T, Schneider J, Kellenberger C, Martin-Fiori E,

8 1050 Willi U, Holzmann D. Developmental nasal midline masses in children: neuroradiological evaluation. Eur Radiol 2004;14: Lindbichler F, Braun H, Raith J, Ranner G, Kugler C, Uggowitzer M. Nasal dermoid cyst with a sinus tract extending to the frontal dura mater: MRI. Neuroradiology 1997;39: Barkovich AJ, Vandermarck P, Edwards MS, Cogen PH. Congenital nasal masses: CT and MR imaging features in 16 cases. Am J Neuroradiol 1991;12: Posnick JC, Bortoluzzi P, Armstrong DC. Nasal dermoid sinus cysts: an unusual presentation, computed tomographic scan findings, and surgical results. Ann Plast Surg 1994;32: M. Hanikeri et al. 25. Pollock RA. Surgical approaches to the nasal dermoid cyst. Ann Plast Surg 1983;10: Weiss DD, Robson CD, Mulliken JB. Transnasal endoscopic excision of midline nasal dermoid from the anterior cranial base. Plast Reconstr Surg 1998;101: Morrissey MS, Bailey CM. External rhinoplasty approach for nasal dermoids in children. Ear Nose Throat J 1991;70: Mankarious LA, Smith RJ. External rhinoplasty approach for extirpation and immediate reconstruction of congenital midline nasal dermoids. Ann Otol Rhinol Laryngol 1998; 107: Carroll C, Gaffney R, McShane D. Congenital nasal dermoids in children. Int J Mol Sci 1997;166: