Case Letter

Vulvar Syringoma

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Practice Points

  • Ensure adequate depth of biopsy to assist in the histologic diagnosis of syringoma vs microcystic adnexal carcinoma.
  • Vulvar syringomas also may contribute to notable pruritus and ultimately be the underlying etiology for secondary skin changes leading to a lichen simplex chronicus–like phenotype.


 

References

To the Editor:

Syringomas are common benign tumors of the eccrine sweat glands that usually manifest clinically as multiple flesh-colored papules. They are most commonly seen on the face, neck, and chest of adolescent girls. Syringomas may appear at any site of the body but are rare in the vulva. We present a case of a 51-year-old woman who was referred to the Division of Gynecologic Oncology at the University of Alabama at Birmingham for further management of a tumor carrying a differential diagnosis of vulvar syringoma vs microcystic adnexal carcinoma (MAC).

A 51-year-old woman presented to dermatology (G.G.) and was referred to the Division of Gynecologic Oncology at the University of Alabama at Birmingham for further management of possible vulvar syringoma vs MAC. The patient previously had been evaluated at an outside community practice due to dyspareunia, vulvar discomfort, and vulvar irregularities of 1 month’s duration. At that time, a small biopsy was performed, and the histologic differential diagnosis included syringoma vs an adnexal carcinoma. Consequently, she was referred to gynecologic oncology for further management.

Pelvic examination revealed multilobular nodular areas overlying the clitoral hood that extended down to the labia majora. The nodular processes did not involve the clitoris, labia minora, or perineum. A mobile isolated lymph node measuring 2.0×1.0 cm in the right inguinal area also was noted. The patient’s clinical history was notable for right breast carcinoma treated with a right mastectomy with axillary lymph node dissection that showed metastatic disease. She also underwent adjuvant chemotherapy with paclitaxel and doxorubicin for breast carcinoma.

After discussing the diagnostic differential and treatment options, the patient elected to undergo a bilateral partial radical vulvectomy with reconstruction and resection of the right inguinal lymph node. Gross examination of the vulvectomy specimen showed multiple flesh-colored papules (Figure 1). Histologic examination revealed a neoplasm with sweat gland differentiation that was broad and poorly circumscribed but confined to the dermis (Figures 2A and 2B). The neoplasm was composed of epithelial cells that formed ductlike structures, lined by 2 layers of cuboidal epithelium within a fibrous stroma (Figure 2C). A toluidine blue special stain was performed and demonstrated an increased amount of mast cells in the tissue (Figure 3). Immunohistochemical stains for gross cystic disease fluid protein, estrogen receptor (ER), and progesterone receptor (PR) were negative in the tumor cells. The lack of cytologic atypia, perineural invasion, and deep infiltration into the subcutis favored a syringoma. One month later, the case was presented at the Tumor Board Conference at the University of Alabama at Birmingham where a final diagnosis of vulvar syringoma was agreed upon and discussed with the patient. At that time, no recurrence was evident and follow-up was recommended.

Figure 1. A formalin-fixed specimen from a portion of the vulva showed soft, flesh-colored papules that were later diagnosed as vulvar syringoma.

Figure 2. A and B, Broad, poorly circumscribed vulvar syringoma confined to the dermis (both H&E, original magnification ×2). C, Ductal structures lined by 2 layers of cuboidal epithelium within a fibrous stroma were noted as well as commalike tail structures (H&E, original magnification ×20).


Figure 3. Increased number of mast cells highlighted with toluidine blue stain (original magnification ×10).


Syringomas are benign tumors of the sweat glands that are fairly common and appear to have a predilection for women. Although most of the literature classifies them as eccrine neoplasms, the term syringoma can be used to describe neoplasms of either apocrine or eccrine lineage.1 To rule out an apocrine lineage of the tumor in our patient, we performed immunohistochemistry for gross cystic disease fluid protein, a marker of apocrine differentiation. This stain highlighted normal apocrine glands that were not involved in the tumor proliferation.

Syringomas may occur at any site on the body but are prone to occur on the periorbital area, especially the eyelids.1 Some of the atypical locations for a syringoma include the anterior neck, chest, abdomen, genitals, axillae, groin, and buttocks.2 Vulvar syringomas were first reported by Carneiro3 in 1971 as usually affecting adolescent girls and middle-aged women. There have been approximately 40 reported cases affecting women aged 8 to 78 years.4,5 Vulvar syringomas classically appear as firm or soft, flesh-colored to transparent, papular lesions. The 2 other clinical variants are miliumlike, whitish, cystic papules as well as lichenoid papules.6 Pérez-Bustillo et al5 reported a case of the lichenoid papule variant on the labia majora of a 78-year-old woman who presented with intermittent vulvar pruritus of 4 years’ duration. Due to this patient’s 9-year history of urinary incontinence, the lesions had been misdiagnosed as irritant dermatitis and associated lichen simplex chronicus (LSC). This case is a reminder to consider vulvar syringoma in patients with LSC who respond poorly to oral antihistamines and topical steroids.5 Rarely, multiple clinical variants may coexist. In a case reported by Dereli et al,7 a 19-year-old woman presented with concurrent classical and miliumlike forms of vulvar syringoma.

Vulvar syringomas usually present as multiple lesions involving both sides of the labia majora; however, Blasdale and McLelland8 reported a single isolated syringoma of the vulva on the anterior right labia minora that measured 1.0×0.5 cm, leading the lesion to be described as a giant syringoma.

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