Treatment for orbital dermoid cysts has undergone a shift towards non surgical management after the introduction of sclerotherapy. Foam formation increases the availability of the drug. ¹ Published English literature has established that small dermoid cysts respond well to foam sclerotherapy .²  Sodium-tetra-decyl sulfate (STS) is an anionic surfactant commonly used for foam sclerotherapy. It causes endothelial injury leading to inflammation, intimal necrosis, adventitial fibrosis, and luminal collapse coupled with vascular thrombosis and erythrocyte sludging.³ Use of STS has been described in ophthalmology for the treatment of orbitopalpebral cyst , arterio-venous malformations (AVM),  carotico-cavernous fistulas, lymphatic abnormalities like lymphangiomas and also used as an adjunctive treatment in the large tumors to decrease their blood supply .^4-6

The authors present their results of treatment of large dermoids with foam sclerotherapy using 3% Sodium tetradecyl sulfate, analyzing the cyst shrinkage and cosmetic outcome.

The study was conducted in accordance with the tenants of the Helsinki Declaration, after  obtaining ethical clearance of the Institution. A prospective case series analysis of  14 patients of large Orbital Dermoid, treated in the Oculoplastics and Orbit Unit, Department of Ophthalmology, King George’s Medical University, Lucknow, between August 2018 and July 2019, was done.

Data record included, clinical characteristics of cyst including location and size, pre  intervention computed tomographic scan (CT scan) findings of the cyst, size, volume, density and post intervention outcome including size( on CT scan) and cosmetic acceptibility. For the purpose of the study Dermoid Cyst with shortest axis ≥ 10mm was considered as large. The cyst was outlined in each slice of axial CT scans and the volume was obtained by the iPlan Cranial software.⁷ Cosmetic acceptibility  assessed by patient at six months of treatment was graded as good (acceptable), fair (could have been better ) and poor (not acceptable). Patients with history of trauma or spontaneous inflammation/rupture were excluded.  All procedures were done by a single surgeon after written consent about indication, postoperative complications and possible need of revision  procedure. Superficial dermoid cysts underwent sclerotherapy under direct vision, deep dermoids underwent sclerotherapy under ultrasound guidance.

Technique of sclerotherapy-

After suitable case specific anaesthesia and aseptic part preparation, cyst puncture was done with 18G needle mounted on a 20-cc syringe. Cyst contents (pultaceous material/clear fluid) were aspirated until no more material entered  the syringe. The Tessari method was  used for preparation of foam.⁸  The injected amount of sclerosant was equal to 10% of the total cyst aspirate. This  was based on authors previous experience of  its use in orbito-palpebral cyst.³

 In all cases, a compression dressing was secured in place for 24 hrs.  Topical Moxifloxacin 0.3% ointment twice daily was advised for 3 days at puncture site. Oral antibiotic (Amoxyclav 30 mg. / body weight in 3 divided doses) was given for 1 week. Patients were followed up at day 1, 2-weeks intervals for the first month ,then monthly for two visits followed by one visit at six months from procedure.

Analysis of computerized data of 14 patients is tabulated in table 1. Mean age of the patients was 15.04 + 5.18 years. Patients with superficial dermoids  had younger mean age(10±4.2 years)than  deeper  dermoids(mean age -18 ± 5.29 years). 10/14 (71.4%) patients had superficial dermoids.   Range of density of cyst on CT was from -20 to 190 Hounsfield Unit (HU) (table -2). The mean cyst volume was 10.19 ml (range 6-13 ml). The mean aspirate volume was 7.5 ml (range 4-11 ml).

Table-1: Showing cyst origin, presentation, management and outcome

R= Right, L=Left, Z-F suture= Zygomatico-frontal suture,

All patients were injected intralesional STS under local anaethesia. No intraoperative complication was  encountered. On first post intervention day, all patients had swelling in perilesional tissue  with mild pain , that responded to oral  analgesics.

At 4 weeks , nine patients showed complete resolution of swelling. Three superficial and two deep dermoids had residual lesion. All five  patients underwent  repeat injection of 3% STS, following same dose protocol. Two out of these five patients showed resolution after second injection. Three  failed to respond and were advised surgerical excision.

No complication like skin necrosis or skin pigmentation  was encountered.

Cosmesis was assessed in 11/14 patients, excluding the three that needed surgery. Eight patients reported good cosmetic outcome and 3 reported fair outcome.

Table-2: Demonstrating characteristics of cyst aspirate, and clinical outcome.

Figure-1

1. a) A 26-year-old male with right superomedial cystic swelling with inferolateral dystopia  (b) Same patient 6  monthsfollowing foam sclerotherapy, showing complete resolution of the dermoid cyst but residual fullness due to soft-tissue expansion .

Figure 2:-

(a) CT scan of the orbit showing  a well-defined cystic mass superomedially with bony fossa formation producing mass effect in the form of inferior dystopia (b) CT scan of same patient , 6 months following foam sclerotherapy showing completely resolved cystic lesion with residual sclerosed cystic wall.

Dermoid cysts account for 3–9% of all orbital masses.⁹ Superficial dermoids present at early age due to cosmetic concerns. Deep dermoids attain larger sizes, cause  proptosis and limitation of extraocular movement. In 1995 Bonavolonta et al. reported  early presentation of  exophytic dermoid cyst as compare to endophytic cysts  and deep dermoid.¹⁰

Large dermoids, both superficial and deep require large surgical incisions. In our study, we extended the well established benefits of foam sclerotherapy to these lesions, thus evading the surgical scars. USG guidance provided a handy tool for localization of the deep dermoids during injection procedure.

Clinical benefits and efficacy of  3%STS as a sclerosant are well established.³ The key benefit of delivering sclerosants as foam is to enhance surface area of contact between the drug and cyst wall.¹¹ The amount of sclerosant injected for the purpose of the current study, was in accordance with the author’s previous experience. They had used 3%  STS  in dose equivalent in volume  to 10%of the aspirate volume for the treatment of Orbitopalpebral cysts.⁴

Volume of all cysts was measured with  iPlan Cranial software. This software has been successfully used for measurement of volume of cyst as well as orbital volume.⁷ The contents were predicted on basis of the HU calculated from the CT scan.(table 2) The aspirate volume did not direcly correlate with the cyst volume in all cases. The nature of cyst contents determined the quantity of aspirate. Mucinous contents were more completely evacuated on aspiration whereas pulateous material offered resistance to aspiration thus resulting in inadequate emptying of the cyst. This explains the disparity between cyst volume and aspirate volume.

9/14 cysts with mucinous aspirate showed complete resolution. 5/14 cysts, that had pultaceous aspirate, showed partial resolution after first injection. Of these, two superficial cysts showed residual content of moderate reflectivity on USG, which was re-aspirated and repeat injection was given. The remaining three cysts showed  high reflectivity contents on USG. The contents could not be aspirated satisfactorily. Drug injected in the second injection was .1ml These patients showed no response to second intervention and were  planned for surgical excision. The reason for partial response can be attributed to incomplete aspiration of thick contents that  act as a barrier between the drug and cyst wall.Thus hampering the sclerosing action  of the drug.

11/14 patients were assessed for cosmetic outcome of the sclerotherapy procedure. 3 patients who did not respond to second therapy were excluded from cosmetic assessment as they were planned for surgery. Of the 11 cases majority  reported a good cosmetic outcome (8/11) .2 of the three that reported fair response were dissatisfied due to the residual, minimal diffuse perilesional fullness . These cases were of superficial dermoids. One patient of deep dermoid who reported fair cosmetic outcome attributed it to the residual proptosis.

In 2014 Naik et al² conducted a retrospective study of 4 patients of periorbital dermoid cyst, who were successfully treated with foam sclerotherapy (STS 30 mg/ml). Mean age of study population was 20.2 years. Average volume of cyst aspirate was 3.75 ml. During average follow up of 13.25 months, two patients responded with first injection and two patients required second foam sclerotherapy. No major complication was reported .² Their study differed from ours in that they had smaller sized anterior dremoids, however their outcomes were comparable.

 The authors propose that the outcome of foam sclerotherapy in large orbital dermoids can be predicted prior to the procedure. The objective evidence for prediction for dermoid resolution is supported by HU of the cyst content on CT scan. Higher HU value was seen in cases that showed partial response. Also, contents with higher HU were difficult to aspirate. The consistency and relative volume of the aspirate in relation to cyst size can thus be surrogate indicators for   response to foam sclerotherapy.

To the authors best knowledge, this is the largest study treating large superficial and deep dermoid with foam sclerotherapy. The satisfactory outcome of the procedure in terms of absence of major complication coupled with the ease of performance make foam sclerotherapy a desirable method for treating large dermoids. Limitations of our study is the small sample size.  Also, the cosmetic outcome was evaluated subjectively by the patient. This could be influenced by individual perception.

Foam sclerotherapy is. a minimally invasive, day-care therapeutic option in the armamentarium for the management of dermoid cyst providing good cosmetic outcome.

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