Syringometaplasia: variants and underlying mechanisms

Abstract

Syringometaplasia is an adaptive, benign, metaplastic cellular process that affects the eccrine ducts and glands in response to a variety of physiological or pathological stimuli. Different subtypes of syringometaplasia have been described, including the squamous, mucinous, and adenomatous types. These metaplastic changes have been reported in association with chemotherapeutic agents, as well as with a variety of skin disorders including multiple infectious, neoplastic, and inflammatory skin diseases. In this review, we attempt to shed light on the different patterns of syringometaplasia, its pathogenesis, the plethora of skin conditions in which it may be observed, and the differential diagnoses that should be considered.

Acquired elastotic hemangioma‐like changes and eccrine sweat duct squamous metaplasia in lichen simplex chronicus/prurigo nodularis‐like lesions of the knee and elbow

“…8,9 In our series, new vessel formation can be seen accompanied by a mild inflammatory cell infiltrate. 10 Nerve hyperplasia has been occasionally reported, [11][12][13][14][15][16][17][18][19][20][21][22] but some authors do not consider this rare finding to be a significant criterion. 5 In AEH, the overlying epidermis is usually unremarkable or flattened.…”

“…Another peculiar histopathological finding identified in all the lesions in our study was eccrine duct squamous metaplasia. Metaplastic epithelial changes of eccrine/apocrine ducts are well-known and are likely to represent a reactive process in non-neoplastic (such as inflammatory dermatoses, drug reaction, viral infection), 12,[26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43] and/or neoplastic conditions (ie, basal cell carcinoma, dermatofibrosarcoma protuberans, keratoacanthoma, squamous cell carcinoma), [44][45][46] or be associated with a benign (ie, tubular adenoma) or malignant sweat gland neoplasm (ie, apocrine adenocarcinoma). 47,48 Syringomatous changes of eccrine sweat glands have been documented in PN.…”

Chemotherapy‐induced eccrine squamous syringometaplasia in an infant

“…Although chemotherapy‐induced ESS is well described and associated with several agents, its underlying pathogenesis is not fully understood . Agents associated with ESS include busulfan, carmustine, cytarabine, cyclophosphamide, daunorubicin, doxorubicin, etoposide, cisplatin, 5‐fluorouracil, imatinib, methotrexate, melphalan, mitoxantrone, suramin, thiotepa, vemurafenib, and vincristine . Several authors have proposed that it is the result of damage to the eccrine ducts from high concentrations of chemotherapeutic agents in sweat .…”

“…1 Two types of ESS have been described, chemotherapy-induced and incidental, that can be associated with several disorders. 2 When secondary to chemotherapy, the eruption is characterized by erythematous macules, papules, plaques, or vesicles in a generalized distribution or limited to the extremities, particularly the intertriginous and acral areas. [1][2][3][4] It typically appears 2-39 days after initiation of chemotherapy and has been associated with many agents.…”

“…2 When secondary to chemotherapy, the eruption is characterized by erythematous macules, papules, plaques, or vesicles in a generalized distribution or limited to the extremities, particularly the intertriginous and acral areas. [1][2][3][4] It typically appears 2-39 days after initiation of chemotherapy and has been associated with many agents. 2,3 Despite the many identified causative agents, there are few reports of chemotherapy-induced ESS in children, with only two such cases in the literature.…”