ECCRINE CARCINOMA

 

Etiology.

 

Eccrine carcinoma is a term used for a group of rare, malignant, eccrine neoplasms with a great diversity in histomorphologic features and wide differences in biologic behavior. The common histopathologic denominator is the presence of variable areas of basaloid cells with tubular structures. These tumors have previously been described under different names, including basal cell tumor with eccrine differentiation (eccrine epithelioma), syringoid carcinoma, and eccrine syringomatous carcinoma.

 

Clinical Findings.

 

Lesions show no distinctive clinical features. They present as slowly growing, solitary, nodules, plaques, and tumors on the scalp, extremities, or trunk of older adults.

 

Histopathology.

 

There is a wide spectrum of histopathologic features. Some tumors show confinement to the dermis, whereas others reveal involvement of the subcutis and deeper soft tissues. Lesions may display relatively well-differentiated features with areas of clear-cut ductal differentiation. A subset of lesions exhibits anaplastic features, with only subtle signs of ductal differentiation. Relatively well-differentiated tumors are characterized by basaloid aggregations arranged in strands, solid nests, and dilated or branching tubular structures . Foci with syringomatous features may be present. Perineural invasion is a common finding.

 

Prognosis and Clinical Course.

 

Eccrine carcinoma can be invasive and destructive, with frequent recurrences. Local recurrences are common. Lymph node and distant metastases are observed in some patients.

 

Treatment.

 

Treatment is by wide surgical excision. Sentinel node biopsy may be valuable in diagnosis of lymph node metastases.