A patient with multiple asymptomatic yellow papules on the scalp

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Figure 1a:

Approximately 50 smooth-surfaced, yellow or skin-coloured, dome-shaped papules with diameters ranging from 3–10 mm located on the occipital region

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Figure 1b:

There was a yellowish-red nodule with a diameter of approximately 7 mm among the yellowish papules

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Figure 2a:

The yellowish papules revealed a uniform bright yellow structureless material

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Figure 2b:

The yellowish-red nodule had dilated capillaries on its surface and lipid accumulation below that

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Figure 3a:

A cyst contained eosinophilic keratinous materials located in the dermis, with the cystic wall consisting of several layers of epithelium without a granular layer (H&E, 100x)

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Figure 3b:

Sebaceous gland lobules were observed near the cystic wall (H&E, 100x)

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Figure 3c:

Nodular masses were composed of predominantly lymphocytes and histiocytes in the superficial and mid dermis (H&E, 100x)

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Figure 3d:

Multinucleated giant cells and keratotic material were also present (H&E, 400x)

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Diagnosis

Steatocystoma multiplex accompanied by foreign-body granuloma.

Discussion

Steatocystoma multiplex is a rare and benign skin disorder typically arising during adolescence or early adulthood. Despite the lack of a well-defined aetiology and pathogenesis, studies have demonstrated that mutations in the KRT17 gene are prevalent in many steatocystoma multiplex patients.¹ Steatocystoma multiplex lesions tend to occur in areas of the body that are rich in sebaceous glands, with the most common locations being the trunk, axillae, extremities, face and scalp, and rarely the genitals and breasts.² However, there have been a few reports of lesions that are strictly confined to the scalp. Steatocystoma multiplex is typified by the presence of multiple small, skin-coloured or yellowish cutaneous cysts that are generally asymptomatic. Nonetheless, its clinical presentation can often imitate other frequently encountered dermatological conditions such as acne vulgaris, vellus cysts, and epidermoid or dermoid cysts.²

We report a case of steatocystoma multiplex exclusively localized on the scalp of a 68-year-old woman. Sina et al. described a case of steatocystoma multiplex, which manifested as foreign body granulomas.³ The author proposed that a foreign body granuloma could be formed if the cysts were ruptured spontaneously or by trauma. Presently, various modalities such as CO₂ laser, surgical excision, cryotherapy and isotretinoin have been employed to treat steatocystoma multiplex.² However, counselling is often advised in cases where the lesions are located on the scalp and face since potential treatments may result in scarring. When informed about the benign nature of these lesions, our patient declined further treatment and is presently undergoing regular follow-ups.