Patient presentation
A 53-year-old Caucasian man was referred to our dermatology clinic by his primary care physician for the evaluation of a longstanding slightly pruritic papular eruption. The eruption appeared initially on his arms, then subsequently spread to involve his scalp, face, chest, abdomen and back over a period of 7 years. During this period, multiple crops of similar lesions appeared sequentially on the involved body areas. He had been treated with ciclopirox cream (Loprox) for a presumptive diagnosis of tinea versicolor with no improvement.

His past medical history was significant only for diabetes mellitus and rosacea. He denied the use of any new medications or topical products.

On physical examination, multiple translucent to yellow papules were observed on the patient’s face, scalp, arms, chest and back. Scattered erythematous papules and large pores were also seen on his nose and cheeks. A biopsy from a lesion on his left arm was performed, and results are pending.

What is Your Diagnosis?

Diagnosis: Eruptive Syringoma
S yringomas are commonly encountered, generally asymptomatic appendageal hamartomas found primarily on the face and around the eyes. Eruptive forms of these tumors rarely manifest.1,2 The uncommon eruptive morphology of syringoma, also known as eccrine or eruptive hidradenoma, was first described by Jacquet and Darier in 1887,3 and presents with an abrupt onset of multiple lesions appearing in successive crops on the anterior chest, neck, abdomen, axillae, proximal inner surfaces of the extremities, and/or groin areas. Adolescent and young adult patients are most frequently affected, but the eruption may also occur in young children.4 Eruptive syringoma is commonly chronic and persistent.1,5 Lesions may spontaneously resolve, but most patients experience progressive spread of the
eruption over several years.5 The risk of recurrence, even following successful
treatment, cannot be eliminated.

Clinicopathologic Characteristics of Eruptive Syringoma
Syringomas are benign adnexal neoplasms that arise from the intraepidermal portions of eccrine sweat ducts, and encompass four clinical variants: a localized form, a familial variant, a form associated with Down syndrome, and a generalized type comprised of multiple, eruptive morphologies.6 Lesions are 1-mm to 5-mm translucent to yellow, or flesh-colored to light brown or hyperpigmented papules on the eyelids and face. Symmetrically oriented acral lesions may occur on the wrists and forearms.7

Syringomas, usually asymptomatic, are more common in Caucasians and in adult females at puberty or near middle-age.7-9 Japanese females and Down syndrome patients have a higher incidence of the disease, particularly involving the eyelid.10,11 Syringomas have been found in association with melanocytic nevi, as well as those occurring with milia-like idiopathic calcinosis cutis (MICC).7,12 A link with Ehlers-Danlos syndrome, Marfan’s disease, and atrophoderma vermiculata has also been documented,13 as has scarring and non-scarring alopecia.14,15 The occurrence of eruptive syringoma in conjunction with milia has been documented as well,6,8,16 and may be considered a separate subtype.

Onset of Condition
Generalized eruptive syringoma presents with a sudden onset of successive crops of small skin-colored to brown papules, usually on the anterior aspect of the body during the peripubertal period.17 Unlike other forms of syringoma, eruptive lesions do not show a female preponderance.5 Eruptive syringomas may remain as solitary papules or coalesce into plaques, and are usually asymptomatic, although pruritic lesions may occur more often in warmer months or during mestruation.2,17-19

Rarer forms involve acral and genital sites, in addition to syringomas occurring with other appendageal tumors such as apocrine hidrocystomas.5 An association with diabetes and Down syndrome exists,2,20,21 and the onset of lesions near pubertal age has implicated the possibility of hormonal influence over tumor development.2 Positive expression of progesterone receptors has been identified in eruptive syringomas, but estrogen receptor expression is quite rare.

Theories on the etiology of eruptive syringoma have included effects of high altitude on the sweat apparatus22 and a mast cell-mediated pathogenetic mechanism.23

A clear cell form of eruptive syringoma with glycogen deposition in ducts and positive expression of progesterone receptors has recently been reported in association with diabetes, alluding to possible hormonal influence and decreased or deficient glycogen phosphorylase enzyme in involved skin.2,20

Differential Diagnosis
When syringomas occur in the classic periocular and facial locations, diagnosis is generally straightforward. However, generalized eruptions must be excluded from papular dermatoses in other sites.

In 29 Italian patients studied retrospectively by Patrizi et al.,7 several had lichen planus-like papules, while others showed urticaria pigmentosa-like lesions with positive Darier’s signs.
Occasional mast cells may be seen surrounding syringomas on biopsy and may help explain the similarity of eruptive syringoma with urticaria pigmentosa.27

Other differential diagnoses include xanthomas, flat verrucae, pseudoxanthoma elasticum, steatocystoma multiplex, disseminated granuloma annulare, multiple trichoepitheliomas, eruptive vellus hair cysts, secondary syphilis and even basal cell nevus syndrome.4,9,13,19 Drug eruptions should be ruled out as well.

Treatment Options
Treatment of eruptive syringoma is generally unsatisfactory.1 As syringomas represent epithelial lesions situated in the dermis, excisional techniques are usually required for complete removal, but given their multiplicity, surgery is generally avoided.9 Although several therapeutic options exist, success has been limited.27

Oral retinoids administered over several months are effective in treating eruptive conditions including Cowden syndrome and Muir-Torre syndrome; however, isotretinoin (Accutane) was employed with contrasting results in two reports of eruptive syringoma.5,28

Pruritic lesions may be ameliorated using topical and oral corticosteroids, topical antifungals, and topical retinoids.29 In one case, 1% topical atropine was used successfully.18

Surgical excision, electrocoagulation, electrodessication with curettage, carbon dioxide vaporization, dermabrasion and liquid nitrogen cryotherapy have all been used with some success, although laser treatment has demonstrated somewhat better outcomes.9,30

A recent report of CO2 laser resurfacing after trichloroacetic acid pre-treatment showed acceptable cosmetic results without significant side effects.9 Unfortunately, surgical and chemical lesion destruction may result in scarring and a poor cosmetic result, and neither modality eliminates a recurrence.1,4,5

Our patient was started on desoximetasone (Topicort) cream b.i.d. to affected body areas and metronidazole topical gel (Metrogel) b.i.d. for his rosacea. He has experienced mild improvement.

Call for Cases
If you have a case you’d like to see published, send a write-up (1,200 to 1,500 words) and an image of the patient’s condition to:
Dr. Amor Khachemoune,
Wellman Center for Photomedicine (BAR314)
Department of Dermatology,
Massachusetts General Hospital
Harvard Medical School
40 Blossom Street
Boston, MA 02114
Or, e-mail them to amorkh@pol.net.