History
Apocrine hidrocystomas usually are asymptomatic. No seasonal variation or familial tendencies have been identified. Apocrine hidrocystomas tend to appear during adulthood, grow slowly, and persist indefinitely. [1]
Physical Examination
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. [2, 3, 4, 5, 6]
Apocrine hidrocystomas often appear tense and shiny. The coloration varies from flesh-colored to blue or black (see image below).
Tumors have a predilection for the eyelid, particularly the inner canthus. Tumors may arise on other areas of the head, neck, and trunk. [7] Tumors also have been reported to occur on the penis, in the axillae, and in the anal region. Rare reports describe an apocrine hidrocystoma on the parotid gland [8] and an epibulbar subconjunctival apocrine hidrocystoma. [9]
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).
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Clinical example of apocrine hidrocystoma.
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Histology of apocrine hidrocystoma. Cystic spaces appear empty because sweat is removed during processing. Decapitation secretion often is seen in the lining.
