Apocrine Hidrocystoma: A Chance Finding

Abstract

A male patient, aged 45 years, came to the hospital with a dental complaint. During the examination, a swelling was noticed on the left side of his face, which had been present for 4 years. The patient provided verbal consent to remove the swelling, and subsequent histopathological examination confirmed a diagnosis of apocrine hidrocystoma. Apocrine hidrocystomas are uncommon cystic growths that develop as benign tumors in the sweat glands. Typically, they appear as a single growth, although on rare occasions, they can manifest as multiple tumors. Typically, they are located in the head and neck regions. Herein, we report a classic case of apocrine hidrocystoma.

INTRODUCTION

Hidrocystoma is a noncancerous fluid-filled lesion that arises from the sweat glands, with two types identified: eccrine and apocrine. Moll’s gland cysts are a type of hidrocystoma that occurs along the lower eyelid margin. Although the exact cause is unknown, eccrine hidrocystoma is thought to occur when eccrine secretions are retained, leading to the enlargement of eccrine ducts, while adenomas of the apocrine sweat gland are believed to cause apocrine hidrocystomas. Apocrine hidrocystomas are commonly observed around the eye, neck, and trunk areas, while their occurrence in other parts of the body such as the ears, scalp, chest, shoulders, feet, axillae, and anal region are less common.[1] The condition typically presents as small, skin-colored papules that are asymptomatic, with a size range of 3–15 mm. Although apocrine hidrocystomas are most common in individuals aged 30–70 years, they affect both sexes equally, and the condition is typically solitary, but can occasionally occur in multiple lesions.[2]

Apocrine hidrocystomas typically appear as solitary lesions; however, there have been rare reports of multiple cysts associated with Schopf–Schulz–Passarge and Gorlin-Goltz syndromes.[3] To confirm the diagnosis, it is essential to perform an excision biopsy and histopathology. In this report, we describe a rare case of apocrine hidrocystoma on the face.

CASE REPORT

A 45-year-old male patient visited the hospital with the primary concern of tooth decay. However, on examination, a raised, asymptomatic swelling was observed on the left side of the face over the malar region that had been present for 4 years. There was no record of trauma or notable medical conditions. The skin over the lesion appeared pale, and the lesion was 3 cm ×3 cm in size and soft and fluctuant in consistency. There were no associated symptoms such as changes in size with temperature variation, visual disturbances, bleeding, or discharge. The patient’s consent was obtained to excise the lesion [Figure 1]. Routine investigations were normal, and an excisional biopsy was performed, with differential diagnoses of nevi and epidermoid cyst.

Figure 1.

Photograph showing swelling on the left side of the face over the malar region

On routine microscopic examination, hematoxylin and eosin-stained soft tissue showed a multilocular bilayered dermal cyst. The cyst was lined by an inner layer of secretory cells, which varied in height and showed eosinophilic cytoplasm and luminal decapitation secretion [Figures 2 and 3]. This suggested apocrine differentiation, and the cyst was surrounded by a peripheral layer of elongated myoepithelial cells. No evidence of inflammation was observed. Based on these characteristic histopathological features, a diagnosis of apocrine hidrocystoma of the face was made. The patient was informed about the recurrence of the lesion and was advised to maintain a regular follow-up.

Figure 2.

Photomicrograph showing bilayered dermal cyst (H and E, ×10)

Figure 3.

Photomicrograph showing the inner layer of secretory cells having an eosinophilic cytoplasm (blue arrow) and luminal decapitation secretion (red arrow) (H and E, ×40)

DISCUSSION

Apocrine hidrocystomas are often found in a specific location and have a typical clinical appearance. Therefore, it is essential to differentiate them from other benign cystic skin lesions such as eccrine hidrocystoma, epidermal inclusion cyst, sebaceous cyst, and also other skin lesions such as lymphangioma, hemangioma, and cystic basal cell epithelioma. In addition, malignant lesions such as malignant melanoma and basal cell carcinoma should also be considered due to their atypical features such as blue-black color.[4]

The precise cause of apocrine hidrocystoma formation is uncertain. It is theorized that the blockage or obstruction of the sweat duct system leads to sweat retention and subsequent development of a dilated cystic structure. The adenomatous cystic proliferation of the apocrine glands is believed to be the underlying pathology.[5]

Clinically, the borders of the lesion are not clearly defined, but rather gradually merge with the surrounding skin. While the walls of the cysts are somewhat see-through, they are also thick enough that they do not typically burst on their own. When touched, the cysts can be moved.[3]

The epidermis in hidrocystomas appears normal on histological examination. The cystic cavities are large and lined by cuboidal or columnar apocrine secretory cells with decapitation secretion, periodic acid–Schiff positive, and diastase-resistant granules with a peripheral layer of myoepithelial cells that extends as papillary projections into the dermis. These features are characteristic, and the cyst has no connection with the overlying epidermis.[6] Histological findings matched our case.

The type of treatment administered depends on whether the lesion is singular or multiple. Several medical treatments such as anticholinergic creams, botulinum toxin, trichloroacetic acid, cryotherapy, and carbon dioxide vaporization laser treatment are available, with laser treatment being particularly effective for multiple lesions. Although incision and drainage may be performed for apocrine hidrocystomas, electrosurgical destruction of the cyst wall is often recommended to prevent a recurrence. After removal, these cysts seldom recur.[4,6]

Although rarely encountered by dental surgeons, apocrine hidrocystomas have been documented over the past few years. Table 1 summarizes the review of the literature of cases reported as apocrine hidrocystomas since 2010. The table contains information about age, sex, site, clinical presentation, histopathology, and differential diagnosis of apocrine hidrocystomas.

Table 1.

Apocrine hidrocystoma cases reported since 2010

Author	Age (years)	Sex	Site	Clinical presentation	Histopathology	Differential diagnosis
Verma[6]	67	Female	Face	Multiple, small 1–3 mm dome-shaped, smooth-surfaced papules	Two cystic cavities	Not mentioned
					One was lined by two layers of cuboidal secretory cells resembling cells of apocrine secretory coil
					The other cyst was lined by attenuated epithelium
Vani et al.[3]	75	Male	Upper and lower eyelids bilaterally	Multiple, small (largest measuring 2 cm×2 cm)	Cyst lined by the inner layer of secretory columnar epithelium and the outer myoepithelial cell layer	Not mentioned
			Both malar areas	Translucent cystic papules filled with watery fluid	At places, secretory epithelium showed decapitation
Shukla et al.[7]	31	Female	Both the axillae	Bilateral, mobile, tender masses measuring 8 cm×7 cm in both axillae	Multiple cystic spaces lined by single or double layers of cuboidal to columnar epithelium	Bilateral accessory breasts
				FNAC yielded thick yellowish-greasy aspirate	Outer myoepithelial cell layer represented dilated apocrine glands
					Many cystic spaces contained eosinophilic secretions (decapitation)
Bommakanti and Salma[8]	22	Male	Lateral aspect of the left eye	Single, small, elevated lesion with skin-colored to bluish-black pigmentation	Large cystic cavity lined by columnar cells with decapitation and a peripheral layer of myoepithelial cells	Nevi
					Decapitation secretions stained PAS positive with diastase resistance	Appendageal tumor
						Melanoma
Ovhal et al.[1]	65	Female	Nose, perinasal and periorbital areas	Multiple, papules, tense, skin-colored, and shiny with cystic consistency	Large dilated cystic structure lined by apocrine type of epithelium with papillary projections	Apocrine/eccrine hidrocystoma
				Yellowish serous fluid oozed on pricking the lesion	Decapitation secretions were PAS positive with diastase-resistant granules	Syringoma
						Trichoepithelioma
						Basal cell carcinoma
Poli et al.[9]	69	Male	Left buccal mucosa	Solitary, well-defined, movable, exophytic submucosal mass measuring 21 mm × 15 mm	Cystic wall lined by two or more rows of sweat duct-like epithelium with cubic cells	Not mentioned
				Soft in consistency and yellowish in color	Cubic cells showed decapitation secretion characterized by apical snouts and fringes
Al Hawsawi et al.[2]	65	Male	Around both eyes	Multiple, skin-colored deep-seated vesicular papules	Cystic structures lined by columnar epithelium with decapitation secretions and some apical snouts	Not mentioned
Sharma[4]	42	Female	Scalp	Reddish brown, nontender, well-circumscribed, mobile, recurrent cystic swelling measuring 3 cm × 2.5 cm	Multilocular bilayered dermal cyst lined by inner layer cuboidal and tall columnar secretory cells with luminal decapitation secretion suggesting apocrine differentiation	Not mentioned

PAS: Periodic acid–Schiff, FNAC: Fine-needle aspiration cytology

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Conflicts of interest

There are no conflicts of interest.

Funding Statement

Nil.