Beware frontotemporal dermoids - they may have intracranial extension: a case of a middle cranial fossa cyst

A Unique Case of Frontotemporal Dermoid Cyst Presenting as Orbital Cellulitis

Dermoid cysts are benign developmental anomalies that can occur anywhere along the neuroaxis or embryonic lines of fusion. While intracranial dermoid cysts at the midline frequently have an associated nasal or subcutaneous sinus tract, it is quite rare to encounter an intracranial dermoid cyst off the midline with a lateral sinus tract. Standard practice for the treatment of dermoid cysts is surgical resection to minimize the risks of meningitis, abscess, mass effect, neurologic deficit, and/or death.  A 3-year-old male with a history of DiGeorge syndrome presented with right orbital cellulitis and a right-sided dermal pit. Computed Tomography (CT) imaging demonstrated a dermal sinus tract with an associated lytic bone lesion within the right sphenoid wing and posterolateral orbital wall with intracranial extension. The patient was taken to the operating room in conjunction with plastic surgery for resection of the dermal sinus tract and intraosseous dermoid.  This case presents a rare occurrence of a non-midline, frontotemporal dermal sinus tract associated with a dermoid cyst with intracranial extension presenting with pre- and post-septal orbital cellulitis. Important considerations include preservation of the frontal branch of the facial nerve, preservation of orbital structure and volume, complete surgical resection to prevent infectious complications including meningitis, and a multidisciplinary surgical approach with plastic surgery, ophthalmology, and/or otolaryngology.

Endoscopic Endonasal Surgery for Dermoid Cysts Arising From the Middle Cranial Fossa Floor: A Rare Case Series

OBJECTIVE

Dermoid cysts (DCs) are congenital, slowly growing, and may cause nervous system symptoms. Related literature is limited and mainly includes case reports. We report a case series of DCs originating from the middle cranial fossa floor (MCFF) and investigate their demographic information, clinical characteristics, imaging findings, surgical procedures, and prognostic outcomes.

METHODS

We reviewed the patients with DCs arising from the MCFF undergoing endoscopic endonasal surgery (EES) in our center between 2012 and 2022.

RESULTS

A total of 5 patients with DCs were enrolled (2 males and 3 females), with a mean age of 46.2 years at the onset. All DCs originated from the MCFF with 1 case involving the middle cranial fossa bone and another 1 case affecting the dura mater. One (20.0%) patient had neurological involvement. After admission, all patients received EES with a total resection rate of 100.0% (5 of 5). After a median follow-up of 73.2 months, all patients achieved complete clinical and radiological improvements. No surgical-related complications or relapses were observed during the long-term follow-up.

CONCLUSION

Endoscopic endonasal surgery is considered a safe and effective approach for the treatment of DCs in the MCFF. A larger sample size and longer follow-up time are needed.

Is pre-operative imaging of external angular dermoid cysts in children necessary?

AIM

To investigate the frequency and modality of pre-operative imaging in children with an external angular dermoid cyst and whether this influenced subsequent management.

METHODS

A retrospective study was undertaken to assess the presentation, investigation, treatment and outcomes in children aged less than 16 years with an external angular dermoid cyst. All children who underwent external angular dermoid cyst excision between January 2008 and April 2021 at a regional children's hospital were analysed.

RESULTS

Sixty-one patients (32 boys) were identified. Fifty-four were managed by paediatric surgeons and seven by ophthalmic surgeons. Pre-operative imaging was performed in 19 (31%) patients, including plain radiographs (3), ultrasound scan (14), computerised tomography scan (1), and magnetic resonance imaging scan (2). None of these investigations showed evidence of an intracranial or orbital extension of the cyst or changed management. All cysts were excised under day-case general anaesthesia. There was one minor postoperative complication and two recurrences.

CONCLUSIONS

External angular dermoid cysts rarely communicate through the bone with the orbit or anterior cranial fossa. Routine pre-operative imaging is unnecessary unless there are clinical features such as an atypical location (e.g. temporal), eye signs (e.g. strabismus, proptosis and globe displacement) or a draining sinus.

Frontotemporal dermoid cyst with incomplete dermal sinus tract in an adult: A case report

Background

Non-midline supratentorial dermoid cyst with dermal sinus tract has been rarely reported especially in adults. We recently experienced a noteworthy patient with frontotemporal dermoid cyst with incomplete dermal sinus tract.

Case Description

A 43-year-old female presented with recurrent subcutaneous mass in the left superolateral orbital region. She had a history of active bronchial asthma, which precluded her from contrast-enhanced imaging studies. Plain imaging studies showed a subcutaneous mass which was continuous with an intrasylvian fissure mass by a tract in the sphenoid ridge and the lesser wing of the sphenoid bone. Frontotemporal craniotomy was performed to reset the mass and the tract. Intraoperative finding showed no intradural tumor components. Extradural component was carefully removed focusing attention on the frontal branch of the facial nerve. The pathology was consistent with dermoid cyst and dermal sinus tract. Postoperatively, she had mild facial palsy of the corrugator supercilii (House and Brackmann Grade II). She was discharged home with modified Rankin scale 1.

Conclusion

Dermoid cyst needs to be included in the differential diagnosis of adult-onset subcutaneous mass in the frontotemporal regions. After thorough imaging studies for the presence and extent of the sinus tract, the symptomatic lesion should be excised completely once and for all.

Intraorbital Dermoid Cyst With Zygomaticofrontal Suture Erosion in an Adult

BACKGROUND

Dermoid cysts are squamous epithelium-lined sacs that result from abnormal migration of ectodermal cells. They are typically superficial and present in children. This study reviews a rare patient with a congenital dermoid cyst occurring as a superolateral intraorbital and extraconal mas.

METHOD

Clinical report and review of the literature.

RESULTS

A 27-year-old male presented with progressive left hypoglobus, proptosis, and diplopia. On computed tomography, a 2.0 × 2.1 × 1.1 cm well circumscribed mass centered on, and extended into, the frontozygomatic suture with smooth remodeling of the frontal bone. Magnetic resonance imaging showed heterogeneous T1 and T2 hyperintensity with hypointensity on fat suppression. A dermoid cyst originating from the frontozygomatic suture was suspected. Excision was performed through a left orbitocranial approach with a lateral orbitotomy through an upper eyelid crease incision. The mass occurred in the superior-lateral portion of the left orbit and originated from the intraorbital surface of the zygomaticofrontal suture line with significant bony remodeling without osseous transgression. The mass was removed completely including the lateral portion of the zygomaticofrontal suture. Pathologic examination was consistent with a dermoid cyst. Postoperative examination revealed resolution of his presenting headaches and diplopia.

CONCLUSION

Congenital dermoid cysts occurring within the craniofacial region occur most commonly in the lateral orbit involving the superficial surface of the frontozygomatic suture. This patient represents the rare occurrence of a dermoid cyst originating from the deep surface of the frontozygomatic suture, resulting in delayed presentation and orbital symptoms of hypoglobus and diplopia. Definitive treatment remains complete surgical excision.

The Appropriate Surgical Approach to Frontotemporal Dermoid Cysts in Adult Patients

Because frontotemporal dermoid cysts are superficial masses on the zygomaticofrontal suture, they are usually removed by simple direct excision in pediatric patients. Adult patients, however, require a more involved treatment approach because these cysts may be large and extend deeply into the surrounding tissue. From 2008 to 2015, 33 adult patients with frontotemporal dermoid cysts were treated in our clinic under a new treatment algorithm. Patients with a cyst smaller than 2 cm in diameter were treated using a direct excisional approach without a preoperative computed tomography (CT) evaluation. Patients with a cyst larger than 2 cm in diameter underwent a preoperative CT evaluation to determine the exact location of the cyst. If the cyst invaded the temporal fossa, a hemicoronal approach was used for excision. Cysts that did not cross the lateral orbital rim were removed using a direct excisional approach. Among the 33 patients in the study, 6 patients had cysts smaller than 2 cm in diameter, and 27 patients had cysts larger than 2 cm in diameter. Of the 27 patients with large dermoid cysts, 17 cysts showed temporal fossa invasion and 10 showed no signs of temporal fossa invasion. In all cases, the cyst was completely excised without rupture, and no instances of complications or recurrence were observed. In adults with frontotemporal dermoid cysts larger than 2 cm in diameter, preoperative CT evaluations should be performed. If the evidence suggests that a cyst has invaded the temporal fossa, a hemicoronal approach is required for complete excision.

Intradiploic dermoid cyst of the lateral frontotemporal skull: case report and review of the literature

BACKGROUND

Intradiploic dermoid cysts represent 0.04-0.7% of cranial tumors. Fewer than 20 cases of dermoid cysts occurring in the lateral frontotemporal region with a sinus tract and bony involvement are described, only 7 with intracranial extension. We present the first report of such a lesion arising within the lateral coronal suture. As the literature on this topic grows, the matter of preoperative imaging for soft tissue and bony lesions of the lateral frontotemporal region is evolving, and this report offers a preliminary set of criteria for when imaging is a necessity.

CASE REPORT

A 2-year-old male presented with a bony lesion in the right frontotemporal region. Since birth the lesion had grown commensurately with the patient. Examination revealed an immobile hard mass overlying the right coronal suture with no discernable abnormality. Computed tomography demonstrated a cystic lesion without evidence of intracranial extension. Intraoperatively, the exophytic lesion was fully enclosed by bony matrix, interrupting the coronal suture as it approached the pterion. Following resection, pathology revealed an intradiploic dermoid cyst.

CONCLUSION

Intradiploic dermoid cysts occurring within patent cranial sutures away from the midline are rarely described lesions. Complete surgical resection with careful follow-up is the treatment of choice.