Solitary Reactive Eccrine Duct Proliferation with Prominent Lymphoid Infiltrates (Pseudolymphomatous Syringoma?).

Sir,

Syringomas are common benign skin adnexal tumors that clinically appear as small skin-colored or yellow multiple papules mainly on the skin of periorbital area. The definition of syringoma as neoplasm of the eccrine duct is well accepted. However, some variants possibly induced by inflammation have been reported as reactive eccrine ductal proliferation or reactive syringomatous proliferation.[1] We herein present a case of solitary reactive eccrine ductal proliferation with prominent lymphoid infiltrates.

A 64-year-old Japanese female patient was referred to our department with an asymptomatic red papule on her right cheek with approximately 4-year duration. Physical examination demonstrated a 5–8-mm red ulcerative papule on her right cheek [Figure 1a and b]. She had no skin lesions around the eyelids, chest, or abdomen. Clinical appearances were indicative of cutaneous pseudolymphoma (CPL) or squamous cell carcinoma. A 3-mm punch biopsy specimen demonstrated several ductal structures lined by a double epithelium with cells containing abundant cytoplasm and elongated tadpole-like epithelial cells in the dermis [Figure 1c and d]. There was prominent inflammatory infiltrate surrounding the ductal structures. In addition, massive infiltration of small lymphoid cells was observed. The lymphoid cells did not have apparent atypia. Nodular structures composed of mature lymphocytes were also seen [Figure 1c and e]. No cerebriform cells as seen in T-cell neoplasms including mycosis fungoides were seen. No lymphoepithelial lesions, centrocytes-like cells, and monocytoid B-cells as seen in marginal zone B-cell neoplasm were noted. No nuclear grooves characteristic of mantle cell lymphoma were seen. The epidermis was unremarkable except mild acanthosis. A diagnosis of syringoma with prominent inflammation was made. After the biopsy, the skin lesion was almost distinguished in a month, and the patient did not accept further complete excision.

Figure 1

(a and b) Red ulcerative papule on her right cheek. No skin lesions around the eyelids. Histopathology showing proliferation of eccrine ductal structures. The wall of the ducts is lined by two rows of cuboidal cells with comma-like tails. There was prominent inflammatory infiltrate surrounding the ductal structures. Excessive proliferation of small lymphoid cells was observed. Nodular structures composed of mature lymphocytes were also seen (H and E at [c] ×4, [d and e] ×400)

Syringomas are clinically divided into four types as follows: localized, familial, a type associated with Down's syndrome, and generalized (eruptive syringomas).[2] Uncommon types include lichen planus-like, milium-like, and plaque-type syringomas.[13] However, our case was not consistent with any types of above-reported syringomas. It is reported that eruptive syringomas occur as a consequence of chronic inflammation, suggesting the involvement of inflammatory reaction in the pathogenesis of syringoma.[4] Moreover, several reports of syringomas in scarring alopecia due to lichen planopilaris, prurigo nodularis support the theory of inflammatory process-induced proliferation of parts of the eccrine duct epithelium.[1] These reactive syringomatous proliferation occasionally lacks typical clinical features of a distinct clinicomorphologic entity. In our case, prominent inflammatory infiltrate surrounding the ductal structures, and pseudolymphomatous nodular structures composed of mature lymphocytes were seen. Therefore, it is possible that idiopathic pseudolymphomatous inflammation elicited syringoma in our case. CPL is a reactive lymphoproliferative process that develops in reaction to various known and unknown stimuli,[5] but most cases are idiopathic. Alternatively, CPL might arise secondary to syringoma.

In summary, we demonstrated a case of syringoma with prominent lymphoid infiltrates. To the best of our knowledge, this is the first report of pseudolymphomatous syringoma. However, further clinical reports are desired to establish this type of syringoma.

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Conflicts of interest

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