Eccrine hidrocystoma: a neoformation to be considered in differential diagnoses of facial swellings.

Hidrocystomas are relatively rare cystic skin tumors. The precise histogenetic derivation and the cellular differentiation of these tumors has been largely debated. Usually, the mean age at diagnosis of the patients with eccrine hidrocystomas (EH) is 51.6 years, 54.0 years for females and 32.5 years for males. EH develop predominantly in females (sex ratio 1:6.5). Most patients are asymptomatic; predilection sites are the lower eyelids, nose and lateral canthus. The authors report a rare case of EH of the lower face in a 57-year-old Caucasian male patient presented with mandibular asymmetry due to an asymptomatic neoformation on the left mandibular region. The present report is relevant for the clinical differential diagnoses that a submandibular lesion requires, to exclude neoplasms of osteogenic, mesenchymal, epithelial, vascular or glandular origin. In the case described the histopathological findings, characterized by the presence of partially collapsed, unilocular cyst lined by small, monomoprhous cuboidal epithelial cells with eosinophilic cytoplasm and a highly vascular, slightly edematous stroma, suggested the diagnosis of EH. The standard treatments for EH is surgical excision, which is associated with a high cure rate and a low recurrence rate. In conclusion, in case of EH in the submandibular region, a specific clinical and instrumental diagnosis is very difficult to make, and histopathological diagnosis represents the standard diagnostic procedure.