Apocrine hidrocystoma

 

Apocrine hidrocystomas are benign cystic proliferations of the apocrine secretory glands. Apocrine hidrocystomas most commonly appear as solitary, soft, dome-shaped, translucent papules or nodules and most frequently are located on the eyelids, especially the inner canthus. Apocrine hidrocystomas grow slowly and usually persist indefinitely.

Pathophysiology

The exact stimulus for the development of an apocrine hidrocystoma is unknown. Plausible causes of the closely related eccrine hidrocystoma include occlusion or blockage of the sweat duct apparatus, which results in the retention of sweat and a dilated cystic structure.

Physical

Apocrine hidrocystomas usually occur as solitary translucent papules or nodules. Consistency is fluctuant and cystic. Size varies from a few millimeters to approximately 1.5 cm. Tumors occasionally manifest as multiple lesions, especially when of the eccrine hidrocystoma type.^1,2,3

Apocrine hidrocystomas often appear tense and shiny. The coloration varies from flesh-colored to blue or black

Tumors have a predilection for the eyelid, particularly the inner canthus. Tumors may arise on other areas of the head, neck, and trunk.⁴ Tumors also have been reported to occur on the penis, in the axillae, and in the anal region.

Lesion edges are not well delineated but blend gradually into adjacent skin. Walls, although translucent, are sufficiently thick that they seldom rupture spontaneously.

When incised, apocrine hidrocystomas collapse, and a thin, clear, brownish, or blackish fluid is released. The fluid color of an apocrine hidrocystoma does not result from the presence of melanin or hemosiderin but may result either from the Tyndall phenomenon or the presence of lipofuscin pigment.

Cysts are mobile with palpation and transilluminate.

Apocrine hidrocystomas are not affected by variation in temperature (unlike eccrine hidrocystomas).

Causes

Although the origin of apocrine hidrocystomas is not known entirely, they are believed to be adenomatous cystic proliferations of the apocrine glands.