Vulvar syringomas usually are asymptomatic and noticed during routine gynecologic examination. Therefore, it is believed that they likely are underdiagnosed.5 When symptomatic, they commonly present with constant9 or intermittent5 pruritus, which may intensify during menstruation, pregnancy, and summertime.6,10-12 Gerdsen et al10 documented a 27-year-old woman who presented with a 2-year history of pruritic vulvar skin lesions that became exacerbated during menstruation, which raised the possibility of cyclical hormonal changes being responsible for periodic exacerbation of vulvar pruritus during menstruation. In addition, patients may experience an increase in size and number of the lesions during pregnancy. Bal et al11 reported a 24-year-old primigravida with vulvar papular lesions that intensified during pregnancy. She had experienced intermittent vulvar pruritus for 12 years but had no change in symptoms during menstruation.11 Few studies have attempted to evaluate the presence of ER and PR in the syringomas. A study of 9 nonvulvar syringomas by Wallace and Smoller13 showed ER positivity in 1 case and PR positivity in 8 cases, lending support to the hormonal theory; however, in another case series of 15 vulvar syringomas, Huang et al6 failed to show ER and PR expression by immunohistochemical staining. A case report published 3 years earlier documented the first case of PR positivity on a vulvar syringoma.14 Our patient also was negative for ER and PR, which suggested that hormonal status is important in some but not all syringomas.
Patients with vulgar syringomas also might have coexisting extragenital syringomas in the neck,4 eyelids,6,7,10 and periorbital area,6 and thorough examination of the body is essential. If an extragenital syringoma is diagnosed, a vulvar syringoma should be considered, especially when the patient presents with unexplained genital symptoms. Although no proven hereditary transmission pattern has been established, family history of syringomas has been established in several cases.15 In a case series reported by Huang et al,6 4 of 18 patients reported a family history of periorbital syringomas. In our case, the patient did not report a family history of syringomas.
The differential diagnosis of vulvar lesions with pruritus is broad and includes Fox-Fordyce disease, lichen planus, LSC, epidermal cysts, senile angiomas, dystrophic calcinosis, xanthomas, steatocytomas, soft fibromas, condyloma acuminatum, and candidiasis. Vulvar syringomas might have a nonspecific appearance, and histologic examination is essential to confirm the diagnosis and rule out any malignant process such as MAC, vulvar intraepithelial neoplasia, extramammary Paget disease, or other glandular neoplasms of the vulva.
Microcystic adnexal carcinoma was first reported in 1982 by Goldstein et al16 as a locally aggressive neoplasm that can be confused with benign adnexal neoplasms, particularly desmoplastic trichoepithelioma, trichoadenoma, and syringoma. Microcystic adnexal carcinomas present as slow-growing, flesh-colored papules that may resemble syringomas and appear in similar body sites. Histologic examination is essential to differentiate between these two entities. Syringomas are tumors confined to the dermis and are composed of multiple small ducts lined by 2 layers of cuboidal epithelium within a dense fibrous stroma. Unlike syringomas, MACs usually infiltrate diffusely into the dermis and subcutis and may extend into the underlying muscle. Although bland cytologic features predominate, perineural invasion frequently is present in MACs. A potential pitfall of misdiagnosis can be caused by a superficial biopsy that may reveal benign histologic appearance, particularly in the upper level of the tumor where it may be confused with a syringoma or a benign follicular neoplasm.17
The initial biopsy performed on our patient was possibly not deep enough to render an unequivocal diagnosis and therefore bilateral partial radical vulvectomy was considered. After surgery, histologic examination of the resection specimen revealed a poorly circumscribed tumor confined to the dermis. The tumor was broad and the lack of deep infiltration into the subcutis and perineural invasion favored a syringoma (Figures 2A and 2B). These findings were consistent with case reports that documented syringomas as being more wide than deep on microscopic examination, whereas the opposite pertained to MAC.18 Cases of plaque-type syringomas that initially were misdiagnosed as MACs also have been reported.19 Because misdiagnosis may affect the treatment plan and potentially result in unnecessary surgery, caution should be taken when differentiating between these two entities. When a definitive diagnosis cannot be rendered on a superficial biopsy, a recommendation should be made for a deeper biopsy sampling the subcutis.
For the majority of the patients with vulvar syringomas, treatment is seldom required due to their asymptomatic nature; however, patients who present with symptoms usually report pruritus of variable intensities and patterns. A standardized treatment does not exist for vulvar syringomas, and oral or topical treatment might be used as an initial approach. Commonly prescribed medications with variable results include topical corticosteroids, oral antihistamines, and topical retinoids. In a case reported by Iwao et al,20 vulvar syringomas were successfully treated with tranilast, which has anti-inflammatory and immunomodulatory effects. This medication could have a possible dual action—inhibiting the release of chemical mediators from the mast cells and inhibiting the release of IL-1β from the eccrine duct, which could suppress the proliferation of stromal connective tissue. Our case was stained with toluidine blue and showed an increased number of mast cells in the tissue (Figure 3). Patients who are unresponsive to tranilast or have extensive disease resulting in cosmetic disfigurement might benefit from more invasive treatment methods including a variety of lasers, cryotherapy, electrosurgery, and excision. Excisions should include the entire tumor to avoid recurrence. In a case reported by Garman and Metry,21 the lesions were surgically excised using small 2- to 3-mm punches; however, several weeks later the lesions recurred. Our patient presented with a 1-month evolution of dyspareunia, vulvar discomfort, and vulvar irregularities that were probably not treated with oral or topical medications before being referred for surgery.
We report a case of a vulvar syringoma that presented diagnostic challenges in the initial biopsy, which prevented the exclusion of an MAC. After partial radical vulvectomy, histologic examination was more definitive, showing lack of deep infiltration into the subcutis or perineural invasion that are commonly seen in MAC. This case is an example of a notable pitfall in the diagnosis of vulvar syringoma on a limited biopsy leading to overtreatment. Raising awareness of this entity is the only modality to prevent misdiagnosis. We encourage reporting of further cases of syringomas, particularly those with atypical locations or patterns that may cause diagnostic problems.