I[NTRODUCTION]{.smallcaps} {#sec1-1}
==========================

Congenital facial dermal sinuses are most commonly located in the midline and paranasal regions. Frontotemporal region sinuses are a rare occurrence. However, unlike their cystic counterpart, they notoriously have deeper extensions. Hence, they require detailed imaging and prompt treatment.

We report a case of this rare sinus in a 3-year-old boy which got infected and was found to have an intraorbital extension.

On review of literature, we found that only nine similar cases have been reported.

C[ASE]{.smallcaps} R[EPORT]{.smallcaps} {#sec1-2}
=======================================

A 3-year-old boy presented with pus discharging from the right lower eyelid. He had a previous history of incision and drainage of a right lower-lid abscess done 2 months ago after which the wound had temporarily healed \[[Figure 1](#F1){ref-type="fig"}\].

![Clinical photograph showing the sinus along with lower-lid abscess](JIAPS-24-300-g001){#F1}

A detailed clinical examination revealed that the child had a congenital right temporal region sinus which was communicating with this lower-lid abscess wound. Palpation also revealed a small defect in the temporal bone. There was no associated proptosis or squint.

To assess the anatomy in detail, a computed tomography (CT) scan of the face with three-dimensional (3D) reconstruction was done. This showed a bony defect in the orbital process of the right frontal bone. An intraorbital collection measuring 1.1 cm × 1.2 cm × 2.1 cm was noted causing erosion of the lateral orbital wall. It was abutting the anterior aspect of the lacrimal gland \[[Figure 2](#F2){ref-type="fig"}\].

![Computed tomography face showing intraorbital extension and three-dimensional-reconstructed computed tomography image showing bony defect in the right temporal bone](JIAPS-24-300-g002){#F2}

A thorough debridement of the lower lid abscess was repeated following which the child was started on long-term antibiotic therapy for 6 weeks.

During definitive surgery, a lateral orbitotomy incision was used to expose the lateral intraorbital region. There was thick, pultaceous material within a cyst wall suggestive of a ruptured dermoid cyst.

The cyst was removed piecemeal and the bony defect was defined and curetted. The temporal sinus was cored out up to the bony defect and excised. The abscess cavity on the lower lid was also curetted via a separate incision on the lower lid.

The postoperative course was uneventful and the child remained asymptomatic at 3-month follow-up with no signs of recurrence.

D[ISCUSSION]{.smallcaps} {#sec1-3}
========================

The commonest location of congenital dermal sinuses in the face is the midline and paramedian region, with an incidence of 36%--78% reported in literature.\[[@ref1]\]

The frontotemporal region is usually affected with a superficial cystic swelling, i.e., the external angular dermoid. The presence of a discharging sinus in this region is a rare occurrence with a rate of about 0.7% as reported by Bonavolontà *et al*.\[[@ref1]\]

Our child had a small congenital sinus in the frontoorbital region with no associated swelling or any ophthalmic complaints and hence was ignored till it developed infectious complications. This stresses on the importance of early evaluation of these lesions even though they appear to be harmless.

The presence of a bony defect in the orbital process of the frontal bone led to the suspicion of an intracranial or intraorbital extension which prompted a CT evaluation. The importance of preoperative assessment for deeper extension in cases of temporofacial sinuses has also been stressed by Yan and Low.\[[@ref2]\]

Although rare, there have been a few reports of sinus tracts associated with superficial frontotemporal dermoid cysts.\[[@ref2][@ref3]\] Our case did not have any superficial swelling as the associated cyst was intraorbital. Nine similar cases have been reported in literature so far to the best of our knowledge \[[Table 1](#T1){ref-type="table"}\].

###### 

Reported cases of frontotemporal sinuses with deep extensions

  Age         Sex                     Year of reporting   Bone involved                     Location of cyst                                                    Approach                                          References
  ----------- ----------------------- ------------------- --------------------------------- ------------------------------------------------------------------- ------------------------------------------------- ---------------------------------
  2.5 years   Female                  1973                Orbital plate of frontal bone     Intraosseous with dural attacment in the region of temporal lobe    Frontotemporal craniotomy                         Cullen\[[@ref4]\]
  5 years     Female                  1975                Zygomatic bone                    Apex of orbit                                                       Lateral orbitotomy                                Pollard and Calhoun\[[@ref5]\]
  1 case      Details not mentioned                                                                                                                                                                               Bonavolontà *et al*.\[[@ref1]\]
  2.5 years   Female                  1998                Frontal and sphenoid bone         Intraosseous with dural attacment in the region of temporal lobe    Local exploration and frontotemporal craniotomy   Hong\[[@ref6]\]
  9 months    Male                    2004                Sphenoid                          Lateral orbit                                                       Lateral/anterior orbitotomy                       Wells and Harris\[[@ref7]\]
  1 year      Female                  2005                Temporal and sphenoidal bones     Intraorbital with intracranial in the region of temporal bone       Hemicoronal incision and lateral orbitotomy       Scolozzi *et al*.\[[@ref8]\]
  2 years     Female                  2012                Temporal bone                     Tract extension upto duramater of the temporal lobe                 Local exploration and intracranial                Naderi *et al*.\[[@ref9]\]
  3 years     Female                  2016                Greater wing of sphenoid bone     Intraosseous with dural attachment in the region of temporal bone   Hemicoronal incision with frontal craniotomy      Bliss *et al*.\[[@ref10]\]
  4 years     Female                  2017                Sphenoid                          Intraorbital with intracranial in the region of temporal bone       Local exploration and intracranial                Kwon *et al*.\[[@ref11]\]
  4 years     Male                    2017                Orbital process of frontal bone   Lateral orbit                                                       Lateral orbitotomy                                Present case

Most of these lesions presented with complications of infection.\[[@ref1][@ref2][@ref3][@ref4][@ref5][@ref6][@ref7][@ref8][@ref9][@ref10][@ref11]\]

In all the cases, involvement has been limited to just above the dura without any intradural extension.\[[@ref1][@ref2][@ref3][@ref4][@ref5][@ref6][@ref7][@ref8][@ref9][@ref10][@ref11]\]

The approach to these sinuses has been a local exploration, a lateral orbitotomy, or a wider hemi coronal incision. For removal of the intracranial extension, a widening of the existing bony defect or a frontotemporal craniotomy has been sought.

In our case, we preferred the lateral orbitotomy approach with widening of the bony defect to remove the entire lesion albeit piecemeal. This gave a good cosmetic result postoperatively with minimal facial dissection.

C[ONCLUSION]{.smallcaps} {#sec1-4}
========================

Congenital frontotemporal region sinuses are a rare occurrence. However, their presence is an indicator of deeper extension.

Further evaluation with radiological imaging helps to confirm deeper extension prior to surgery for complete removal.

Prophylactic surgical excision may be warranted for avoiding serious complications.

Declaration of patient consent {#sec2-1}
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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 {#sec2-2}
---------------------------------

Nil.

Conflicts of interest {#sec2-3}
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There are no conflicts of interest.
