Eccrine Cyst (Hidrocystoma) of the Inner Canthus: A Rare Entity With Immunohistologic Confirmation

Area of Science:

• Dermatopathology
• Ophthalmology
• Histology

Background:

• Eccrine hidrocystomas are rare benign cystic tumors originating from sweat glands.
• Eyelid involvement is uncommon, with only one previous histopathologically confirmed case reported.
• This study presents a second instance, contributing to the understanding of these lesions.

Observation:

• A ruptured cyst was surgically removed from the left inner canthus of a 68-year-old female patient.
• Histopathological examination revealed a cyst lined by double-layered cuboidal epithelium.
• The cyst lumen contained amorphous material.

Findings:

• Immunohistochemical analysis showed strong positivity for cytokeratins 5/6 and 14 in the cyst lining cells.
• Weak reactivity was observed with cytokeratin 7.
• These specific cytokeratin expression patterns are consistent with eccrine differentiation.

Implications:

• This case confirms the existence of eccrine hidrocystomas of the eyelid.
• It provides further diagnostic criteria for differentiating these lesions from other eyelid cysts.
• Adds to the limited literature, aiding future clinical and pathological diagnosis.