|Year : 2019 | Volume
| Issue : 2 | Page : 73-75
Endoscope-assisted excision of recurrent frontotemporal dermoid: A case report
Renu Rajguru1, Anubhav Singh2, TS Lingaraju3
1 Department of ORL-HNS, INHS Asvini, Mumbai, Maharashtra, India
2 Department of ORL-HNS, Military Hospital, Bhopal, Madhya Pradesh, India
3 Department of Neurosurgery, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka, India
|Date of Submission||21-Jul-2019|
|Date of Acceptance||29-Sep-2019|
|Date of Web Publication||25-Nov-2019|
Dr. Anubhav Singh
Department of ORL-HNS, Military Hospital, Bhopal, Madhya Pradesh
Source of Support: None, Conflict of Interest: None
Craniofacial dermoids develop as a result of sequestration of epidermal and adnexal components within mesodermal and neuroectodermal structures during embryonic development. Frontotemporal dermoids are the most common of these and usually present as slow-growing masses without discharging sinus or deep bone or intracranial extension. We present a case of recurrent frontotemporal dermoid with discharging sinus and invasion into the sphenoid bone with bone erosion and intracranial extradural extension of dermoid. The patient was managed with surgical excision and clearance of dermoid. Complete surgical excision was ensured with the help of angled nasal endoscopes. Endoscopes provide a wide angle of view and are available in various angles, hence helping in complete visualization of bony cavity and clearance of its contents. The use of endoscopes in surgeries of craniofacial dermoids can help in reducing chances of residual lesion and requirement of subsequent revision surgery and ensure a better cosmesis.
Keywords: Dermoid cyst, endoscopes, sphenoid bone
|How to cite this article:|
Rajguru R, Singh A, Lingaraju T S. Endoscope-assisted excision of recurrent frontotemporal dermoid: A case report. Ann Indian Acad Otorhinolaryngol Head Neck Surg 2019;3:73-5
|How to cite this URL:|
Rajguru R, Singh A, Lingaraju T S. Endoscope-assisted excision of recurrent frontotemporal dermoid: A case report. Ann Indian Acad Otorhinolaryngol Head Neck Surg [serial online] 2019 [cited 2020 Sep 19];3:73-5. Available from: http://www.aiaohns.in/text.asp?2019/3/2/73/271597
| Introduction|| |
Craniofacial dermoid cysts usually develop along the lines of embryonic fusion. Dermoids may be congenital or acquired and are believed to develop due to sequestration of epidermis and adnexa within deeper mesodermal and neuroectodermal structures during embryonic development. They are lined with squamous epithelium and contain adnexal components such as sweat glands, sebaceous glands, and hair.
Endoscopes are being increasingly used in otolaryngologic and head-and-neck surgical procedures in novel ways. We report a case of recurrent frontotemporal dermoid with draining sinus and extension into a greater wing of Sphenoid bone that was excised under endoscopic visualization.
| Case Report|| |
A 31-year-old male with no known comorbidities presented with a history of painless swelling on the left side temporal region for 1 year. He had undergone excision of the swelling at a different hospital in March 2017, reported on histopathology as stratified squamous epithelium-lined cyst with proliferating sebaceous glands and few hair follicles, consistent with dermoid cyst. Two months postsurgery, the patient developed recurrence of swelling with a discharging sinus. There was no history of fever, irritability, projectile vomiting, seizures, neurological deficits, or any other ear, nose, or throat complaints.
On examination, the patient was conscious and oriented to time, place, and person. There was a discharging sinus in the left temporal region over the scar of previous surgery [Figure 1]a. The otorhinolaryngological and neurological examination was unremarkable.
|Figure 1: (a) Preoperative appearance of the lesion with discharging sinus over the left temporal region, (b) Opening on the lateral skull wall showing contents of the dermoid cyst|
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A contrast-enhanced computed tomography (CT) and magnetic resonance imaging (MRI) of the head were done. CT scan showed heterogeneous density lesion with peripheral enhancement on contrast involving the left sphenoid and frontal bones, measuring 20 mm × 28 mm × 17 mm (Anteroposterior (AP) × Transverse (TR) × Cranio-caudal (CC)), with the erosion of greater wing of the left sphenoid and thinning of posterolateral wall of the left orbit. The lesion extended into the temporal fossa through a defect in bone just posterior to the frontozygomatic suture [Figure 2]. MRI revealed a well-defined, thick-walled lesion which was hyperintense on T2 and isointense on T1 and did not show any suppression on short TI inversion recovery images. No orbital or infratemporal fossa extension was found.
|Figure 2: Preoperative computed tomography scan of frontotemporal dermoid|
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A diagnosis of dermoid cyst – left frontotemporal region – was made. The patient was planned for surgery with neurosurgeons anticipating intradural extension. Written informed consent was obtained from the patient and revision excision of dermoid cyst was carried out under general anesthesia. The cyst was approached through temporal fossa. An elliptical incision was given around the sinus. Mollison's self-retaining mastoid retractors were used to hold the skin flaps. The sinus tract was found leading into the dermoid cyst within the sphenoid and frontal bones. The opening on the lateral wall of the skull was enlarged with drill and Kerrison punch [Figure 1]b, and the cavity was visualized with 4 mm 0° and 30° nasal endoscopes. Endoscopy showed the presence of white cheesy material with few hairs within the bony cavity [Figure 3]a, which was cleared with curette and suction. A drain was placed into the cavity and wound closed in layers. Postoperative period was uneventful, and the drain was removed on the 3rd postoperative day.
|Figure 3: (a) Endoscopic appearance of the dermoid cavity within the sphenoid bone, (b) Postoperative appearance of healed surgical site|
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The excised specimen was sent for microbiological and histopathological examination. Gram-stain showed inflammatory cells with no microorganisms. Histopathology showed a sinus tract lined by stratified squamous epithelium, with subepithelial tissue showing sebaceous glands and hair follicles. The cheesy material from within the cyst showed keratin flakes. There was no evidence of malignancy. The histopathology was thus consistent with a dermoid cyst.
The patient had cosmetically good healing [Figure 3]b and has been asymptomatic thereafter. Repeat imaging done in March 2019 showed soft tissue obliterating the bony cavity without any evidence of recurrence or residual disease [Figure 4].
|Figure 4: Postoperative computed tomography appearance of the surgical site|
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| Discussion|| |
Craniofacial dermoids are believed to occur as a result of inclusion of ectodermal tissues during neural tube closure. They are usually seen in the midline but also occur along the lines of epithelial fusion. During cranial development, the ectoderm is in contact with the periosteum at the suture lines, which may get pinched off from the skin surface as the suture lines close, leading to the formation of craniofacial dermoid cysts. The resultant lesions can range from simple, cystic masses to those with draining sinuses and intracranial extension.
Bartlett et al. classified craniofacial dermoids as frontotemporal, orbital, and nasoglabellar. Frontotemporal dermoids are the most common of these and present as slow-growing, superficial masses without any deep extension or discharging sinuses. In the current case, the discharging sinus occurred after a previous incomplete surgical excision and hence is not regarded as a key feature of this case.
A majority of dermoid cysts are expected to manifest clinically by the age of 6 years. However, some dermoids remain unnoticed till later life as they slowly and progressively grow, resulting in structural or functional impairment, pain, draining sinus, and infection. The current case represents a late presentation of frontotemporal dermoid in the fourth decade of life.
Frontotemporal dermoids are usually described as superficial lesions with rare chances of intracranial extension or extension into the bony walls of the orbit. Lacey et al. in a retrospective review of 24 cases observed bone invasion in three cases with a discharging sinus. They recommended that all cases of frontotemporal dermoid cysts with the sinus tract must have a preoperative imaging to define bone invasion, in the presence of which an aggressive exposure and resection of outer table of skull bone be undertaken to prevent recurrence. Isolated case reports have highlighted deeper invasion of dermoid into the skull bones with intracranial extension and the importance of imaging prior to surgical excision. The current case highlights the importance of preoperative imaging to identify bone invasion and intracranial extradural extension.
Clearance of Dermoid from within the bony cavity can be aided by use of a powered drill. An endoscope or a microscope can help in obtaining magnified view of the cavity. In the current case, the skull bone opening was enlarged with a drill and Kerrison bone punch; thereafter, 0° and 30° viewing angle 4 mm diameter endoscopes were introduced to guide clearance from difficult to visualize areas. Endoscopes provide a wide field of view and help in visualization of recesses within the cavity that were otherwise difficult to reach.
To conclude, frontotemporal dermoids should be optimally imaged to assess deep-tissue invasion, and complete surgical clearance should be ensured to reduce chances of residual or recurrent lesions.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]