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Well‐differentiated neuroendocrine tumors in skin: Terminology and diagnostic utility of cytokeratin 5/6 and p63
Author(s) -
Panse Gauri,
Cowper Shawn E.,
Leffell David J.,
Pulitzer Melissa,
Ko Christine J.
Publication year - 2017
Publication title -
journal of cutaneous pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.597
H-Index - 75
eISSN - 1600-0560
pISSN - 0303-6987
DOI - 10.1111/cup.12952
Subject(s) - pathology , medicine , cytokeratin , stain , differential diagnosis , immunohistochemistry , neuroendocrine tumors , staining
Background Well‐differentiated neuroendocrine tumors (WDNETs) in skin include metastases from visceral primary sites and very uncommonly, primary cutaneous carcinoid tumors. Cutaneous WDNET may present a diagnostic challenge and in particular can be mistaken for a benign skin adnexal tumor. In contrast to cutaneous adnexal tumors, metastatic adenocarcinomas to the skin are cytokeratin 5/6 (CK5/6) and p63 negative in the majority of cases. It is unclear if failure to stain with CK5/6 and p63 would be helpful in differentiating WDNETs from cutaneous adnexal neoplasms. Methods We reviewed 10 cases of cutaneous WDNETs (8 cases of metastatic disease and 2 presumed primary carcinoid tumors of the skin) and performed immunohistochemical stains for CK5/6 and p63 on all cases. Results All 10 cases were negative with both CK5/6 and p63. Conclusion Negative staining for CK5/6 and p63 can be helpful to distinguish WDNETs from cutaneous adnexal neoplasms. It is important to consider WDNETs in the differential diagnosis of cutaneous adnexal neoplasms as low‐grade tumors may be the first sign of aggressive metastatic disease.