Apocrine Hidrocystoma of the Scalp with Positive Transillumination

A 45-year-old male presented to our dermatology clinic with a solitary, asymptomatic nodule that had gradually increased in size over six months on his scalp. On physical examination, a well-circumscribed, smooth, nodule measuring 2 cm in diameter was observed on the left parietal region of the scalp [Figure 1]. The lesion exhibited positive transillumination when a penlight was placed against it, indicating a cystic nature [Figure 2]. The cyst was carefully dissected and removed in its entirety without rupture. Histopathological examination of the excised lesion confirmed the diagnosis of apocrine hidrocystoma [Figure 3].

Figure 1.

Apocrine hidrocystoma on the occipital part of the scalp

Figure 2.

Positive transillumination of apocrine hidrocystoma

Figure 3.

Histopathology of apocrine hidrocystoma showing decapitation secretion (H&E, 40x)

Apocrine hidrocystoma is an uncommon, benign cystic tumor that arises from the secretory portion of the apocrine sweat glands.[1] Positive transillumination is a useful clinical feature that aids in differentiating cystic lesions from solid nodules. Tumors that may present with transillumination include digital mucinous pseudocysts, digital myxoid cysts, ganglion cysts, and peripheral nerve sheath tumors such as neurofibromas and neurilemmomas.[2,3,4]

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Conflicts of interest

There are no conflicts of interest.

Funding Statement

Nil.