Proliferating Trichilemmal Cyst Presenting as Limbal Mass

Dr Pawan Prasher

Sri Guru Ram Das Institute of Medical Sciences and Research, Amritsar, India

Financial Disclosure: No financial interest

Introduction– Management of limbal mass can be challenging in terms

of establishing clinical diagnosis, histopathology and treatment

– Differential diagnoses for limbal mass include pinguecula, pterygium, papilloma, nodular episcleritis, phlycten, nevus, granuloma, dermoid, lymphoma, CIN, malignant melanoma, squamous cell carcinoma, ectopic lacrimal gland tissue, hemangioma, nodular fasciitis, amyloidosis and in association with dermatological disorders like xeroderma pigmentosum

– Histopathology plays a key role in the management of suspicous lesions

– Presented herein, is a case of proliferating trichilemmal cyst that presented as a limbal mass

Case Report• A 25-year-old female

presented with gradually increasing mass in the left eye for over one month.

• Associated with redness, mild irritation and watering.

• No history of trauma, surgery or any similar episode in the past.

• No history of any associated ocular or systemic illness

Ocular examination• Visual acuity was 20/20 both eyes• Slit lamp examination showed

elevated nodular mass measuring 5 x 4 x 3mm at nasal limbus of left eye.

• The mass had gelatinous, pearly white appearance in the center with dilated vessels in the peripheral part.

• Associated epithelial irregularity of the adjacent cornea.

• The mass appeared to be mobile over the underlying tissues and was non-tender.

• The rest of ocular and systemic examination was unremarkable.

• The patient underwent excisional biopsy of limbal mass • Under local peribulbar anaesthesia, the mass was

excised with 2mm surrounding healthy conjunctival tissue

• The mass was found not to be adherent to the underlying tissues

• The excision was followed by application of 0.04% mitomycin-C application on the scleral bed for 2 minutes

• Excised mass was sent for histopathology• Post-operatively patient was put on topical moxifloxacin

eye drops four times daily, prednisolone eye drops four times daily and ciprofloxacin eye ointment at bedtime

Histopathology• Presence of islands of

squamous cells with keratin filled cysts in the substantia propria.

Histopathology

• Cysts lined by stratified squamous epithelium

• The squamous cells showed abrupt keratinization, without any granular layer, consistent with trichilemmal keratinization

• There was no evidence of atypia.

• There was formation of early pyogenic granuloma at 2 weeks post-op which resolved on increasing the frequency of topical prednisolone eye drops to every 2 hours.

• At one year post-op, patient showed well healed conjunctiva with no evidence of recurrence in the area of excision.

Discussion• Trichilemmal cyst arises from outer root sheath

epithelium of hair follicle• Also known as wen, pilar cyst or isthmus-catagen cyst• Most often found on the scalp, but has also been

reported to occur in buccal mucosa• Formation of proliferating trichilemmal cyst in the

current case could be as a result of implantation of hair follicle cells from eyelashes while rubbing or migration from caruncle

• Management of trichilemmal cysts includes wide local excision with continued long-term surveillance

Discussion• Being keratinous cysts, these cysts are similar to

epidermal cysts• Key differentiating feature: trichilemmal

keratinization• In this pattern, cells undergo an abrupt transition

from the stratum spinosum to the keratinized layer without the formation of the granular layer

• Rarely, trichilemmal cysts can become malignant

Conclusions

• Proliferating trichilemmal cyst can present as a gradually progressing limbal mass

• It is a benign condition that needs to be distinguished from malignant squamous cell carcinoma which has similar presentation but different prognosis

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