Derm Dx: A translucent ‘bump’ on the lower eyelid

Apocrine hidrocystomas are 1-3 mm translucent papules that usually occur as solitary lesions on the face or scalp. They are more commonly seen in women and appear skin-colored to bluish in color. Apocrine hidrocystomas are believed to be proliferations of...

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Apocrine hidrocystomas are 1-3 mm translucent papules that usually occur as solitary lesions on the face or scalp. They are more commonly seen in women and appear skin-colored to bluish in color. Apocrine hidrocystomas are believed to be proliferations of apocrine sweat gland coils. 

Hidrocystomas can be classified as apocrine or eccrine depending on the histologic features. Apocrine hidrocystomas are unilocular to multilocular cysts in the dermis that are lined by cuboidal epithelial cells with bulbous protrusions, also known as “snouting.” Luminal decapitation secretion is another characteristic histopathologic finding.

Eccrine hidrocystomas contain clear fluid and tend to be lined by two layers of cuboidal, flattened epithelium. The presence of human milk-fat globulin antigen expression differentiates apocrine from eccrine hidrocystomas. 

Schöpf-Schulz-Passarge syndrome (SSPS) is characterized by multiple hidrocystomas on the eyelids with apocrine secretions, along with palmoplantar syringofibroadenomas. Hypodontia, hypotrichosis, nail dystrophy and other adnexal tumors may also be seen in patients with SSPS.

Syringomas are 1-3 mm benign adnexal neoplasms occurring most commonly on the forehead and cheeks. Lesions may also occur on the penis, vulva, abdomen or axillae. They are almost always multiple and exhibit sweat duct differentiation. 

Cystic basal cell carcinoma may resemble hidrocystomas, appearing as dome-shaped, blue-gray nodules.

An epidermal inclusion cyst is a benign tumor of the skin that presents as a nonfluctuant cystic mass located most frequently on the face, neck or trunk. Stratified squamous epithelial lining with keratohyalin granules is a characteristic histologic finding.

Diagnosis & Treatment

A definitive diagnosis can be reached through biopsy, which is crucial to rule out more serious conditions such as basal cell carcinoma. Histopathologic findings, as described above, include dermal cystic spaces lined by cuboidal to columnar epithelial cells with decapitation secretion.

Apocrine hidrocystomas can be treated with simple excision. Other treatment options include electrodessication, and CO₂ or pulsed dye laser. Multiple eccrine hidrocystomas may be treated with topical atropine ointment 1% or scopolamine cream 0.01%. However, success is variable and pupil size may increase as a side effect.

Laura Olympia Karas, BA, is a senior medical student at Baylor College of Medicine in Houston, where Adam Rees, MD, is a resident in the Department of Dermatology.