Eccrine Carcinoma Workup

Updated: Sep 22, 2016
  • Author: Georgina Marie Ferzli, MD, MS; Chief Editor: Dirk M Elston, MD  more...
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Workup

Imaging Studies

Because of the rarity of eccrine carcinomas, specific guidelines for the investigation of possible disseminated disease have not been established.

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Procedures

A shave, punch, or excisional biopsy should be performed to obtain a representative sample of the eccrine carcinoma lesion; this sample should be sent for histopathologic evaluation to make the initial diagnosis.

Because of the high rate of local recurrence (10-70%) following conventional surgical excision, Mohs micrographic surgery appears to be the method of choice for removal of eccrine carcinomas. [17] Wildemore et al [18] reported on 19 cases of non–microcystic adnexal carcinoma (MAC) malignant eccrine neoplasms that were treated by Mohs micrographic surgery. No reported recurrences were found over an average follow-up period of 29 months.

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Histologic Findings

Several eccrine carcinoma subtypes bear histologic resemblance to a well-described benign counterpart; these tumors are named accordingly, and the microscopic distinction between benign and malignant usually is made based on extent of invasion, asymmetry at scanning magnification, and degree of nuclear atypia. In contrast, the group of primary eccrine cancers without features of benign adnexal tumors is less readily recognizable and includes eccrine adenocarcinoma, mucinous eccrine carcinoma, adenoid cystic eccrine carcinoma, and aggressive digital papillary adenoma/adenocarcinoma. These tumors often may be confused with visceral adenocarcinoma metastatic to the skin and represent important diagnostic considerations when adenocarcinoma is encountered in the skin in the absence of a known extracutaneous primary. [19]

Eccrine adenocarcinoma generally resembles a moderately to poorly differentiated adenocarcinoma, with regional variation ranging from true ductules in some areas to infiltrative, nonglandular anaplastic cells in other areas, to glycogenated cellular zones in other areas. Contiguity with benign eccrine structures or with overlying epidermis is not seen.

Mucinous eccrine carcinoma is characterized histologically by solitary and nested anaplastic cells floating in pools of mucin within the dermis. Thin strands of fibrous tissue serve to compartmentalize these "lakes" of mucin.

Adenoid cystic eccrine carcinomas most often are seen as tumors of major and minor salivary glands but rarely may be encountered as primary cutaneous tumors remote from salivary apparatus. This tumor exhibits a population of uniform basaloid cells forming cribriform and tubular structures, usually with evidence of mucin and of hyaline surrounding cellular masses. Perineural invasion is prevalent and should be sought specifically.

Aggressive digital papillary adenoma/adenocarcinoma exhibits cystic zones manifesting papillary infoldings and lined with benign cuboidal epithelium, more cellular zones of atypical adenomatous hyperplasia, and areas of overt adenocarcinoma. Whether aggressive digital papillary adenoma (ADPA) can be distinguished histologically from aggressive digital papillary adenocarcinoma (ADPA) has been questioned; it now is advised that all aggressive digital papillary (ADP) tumors be designated as adenocarcinoma.

Notwithstanding the above histologic descriptions, the distinction between subtypes and even the designation of eccrine tumor may be difficult, if not impossible, in select cases based on light microscopy alone. In these instances, a stain of eccrine-type enzymes (eg, succinic dehydrogenase, amylophosphorylase) may be obtained. The presence of ferritin also is helpful in determining the eccrine origin of a tumor [20] ; such immunostains as CEA, EMA, EKH5, and EKH6 also may be used.

See the images below.

Eccrine carcinoma pathology. Basaloid cells invadi Eccrine carcinoma pathology. Basaloid cells invading the dermis. Courtesy of DermNet New Zealand (http://www.dermnetnz.org/topics/eccrine-carcinoma-pathology/).
Eccrine carcinoma pathology. Tubule and gland form Eccrine carcinoma pathology. Tubule and gland formation, along with clear cell change. Courtesy of DermNet New Zealand (http://www.dermnetnz.org/topics/eccrine-carcinoma-pathology/).
Eccrine carcinoma pathology. Tubule and gland form Eccrine carcinoma pathology. Tubule and gland formation infiltrating the sclerotic dermis; eccrine differentiation can be seen at high power. Courtesy of DermNet New Zealand (http://www.dermnetnz.org/topics/eccrine-carcinoma-pathology/).
Eccrine carcinoma pathology. Tubule and gland form Eccrine carcinoma pathology. Tubule and gland formation infiltrating the sclerotic dermis; eccrine differentiation can be seen at high power. Courtesy of DermNet New Zealand (http://www.dermnetnz.org/topics/eccrine-carcinoma-pathology/).
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