Page 43 - The Netter Collection of Medical Illustrations - Integumentary System_ Volume 4 ( PDFDrive )

Plate 2-16 Benign Growths

Hidrocystomas of the eyelid may appear similar
to a chalazion or a basal cell carcinoma. They
may appear translucent and easily rupture. They
are almost always asymptomatic.

HIDROCYSTOMA

Hidrocystomas, also known as eccrine hidrocystomas,
are common benign skin tumors that are most fre-
quently found along the eyelid margin. These benign
tumors have a typical appearance and no malignant
potential. Most often, they manifest as solitary, asymp-
tomatic papules.
Clinical Findings: Eccrine hidrocystomas manifest
as solitary, translucent, pale, clear to blue or light purple
papules. They have a smooth surface and a dome shape. Low power. A well-circumscribed cystic lining is seen in the
Eccrine hidrocystomas are soft; they feel as if pressure dermis. Minimal surrounding inflammation is present.
could easily rupture their cystic wall. Puncturing of the
cyst wall with a 30-gauge needle causes drainage of a
thin, watery fluid. These tumors are almost always
asymptomatic. They can occur at any age but are far
more common after the fourth decade of life. No dif-
ference in incidence has been observed based on race
or gender. Lesions are typically small, 5 mm to 1 cm in
diameter, and can fluctuate in size. It is not uncommon
for a patient to relate that the tumor enlarges during
physical exercise, only to shrink after a few days. If
ruptured, these tumors drain a thin, watery liquid, and
the cystic cavity deflates. Although they are almost
always solitary, there are reports of hundreds of these
tumors developing in some patients. Large eccrine Chalazion; lid everted.
hidrocystomas occurring in atypical locations have also Tender nodule of the
been described. eyelid.
The main differential diagnosis is between eccrine
hidrocystoma and basal cell carcinoma. Cystic basal cell
carcinomas can have an identical appearance; however,
the patient history will be quite different. Basal cell
carcinomas typically enlarge over time and ulcerate,
causing bleeding of the ulcerated papule. Hidrocysto-
mas rarely, if ever, ulcerate or bleed. If left alone, they
only transiently increase in size and never get much
larger than 1 cm in diameter, and usually they are
much smaller. A biopsy for pathological evaluation is High power. The lining is made up of two cell layers of
diagnostic. cuboidal epithelium. There is a small amount of dermis
Pathogenesis: Hidrocystomas develop from the between the cyst and the overlying epidermis.
eccrine apparatus. It is believed that a portion of the
eccrine duct within the dermis becomes occluded. This
occlusion causes a buildup of eccrine secretions proxi-
mal to the blockage. Once enough fluid collects, a Histology: A lone cystic space is seen within the consistent with eccrine gland secretions. There is no
translucent papule becomes evident on the surface dermis. The cyst is well circumscribed, and the lining evidence for sebaceous gland or apocrine gland secre-
of the skin. No genetic abnormalities of the involved of the cyst contains two layers of cells. The cells are tion or derivation.
eccrine duct have been discovered, and this cystic cuboidal and have an eosinophilic cytoplasm. The cell Treatment: Most eccrine hidrocystomas are biopsied
formation is most likely caused by damage from super- wall has no myoepithelial cell component. The cysts to make sure they are not actually basal cell carcinomas.
ficial trauma to the skin and the underlying eccrine are found near eccrine gland structures. There is They rarely recur after biopsy. If they do recur, no
ducts. Sun damage to the eccrine ducts has been theo- minimal to no inflammatory infiltrate surrounding treatment is required. Surgical excision is the definitive
rized to play a role, although this theory has yet to be the cyst. The central cavity of the cyst contains an treatment and is curative. Hidrocystomas almost never
vigorously tested. small amount of lightly eosinophilic material that is recur after excision.

THE NETTER COLLECTION OF MEDICAL ILLUSTRATIONS 29