PhiliPPine Journal of otolaryngology-head and neck Surgery Vol. 28 no. 1 January – June 2013
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36 PhiliPPine Journal of otolaryngology-head and neck Surgery
The World Health Organization (2005) defines an epithelial-myoepithelial carcinoma (EMC)
as a malignancy composed of two cell types that typically form duct-like structures.1 We present
herein an archival case from the parotid gland.
EMC occurs primarily in the major salivary glands particularly in the parotid where it presents
as a painless, slow-growing mass.1 Microscopic examination shows bi-layered tubular duct-like
structures with pale to clear areas (Figure 1). The inner luminal layer is composed of cuboidal cells
that are of epithelial derivation while the outer layer is composed of polygonal cells that are of
myoepithelial derivation (Figures 2 and 3). The latter typically have abundant clear cytoplasm.1,2
The epithelial-myoepithelial dualism is confirmed using immunohistochemical stains; the
epithelial cells being immunoreactive for low molecular weight keratin and the myoepithelial
cells for S-100 protein, muscle specific actin, vimentin and p63.1, 3
EMC is primarily a tumor of adulthood with peak incidence in the sixth and seventh decades.
First described by Donath et al. in 1972,3 they are rare salivary gland neoplasms with an incidence
of less than 1% arising mainly in the parotid gland4 although they have been documented in
the lungs.5 Perineural and vascular invasion are frequent and recurrence occurs in around 40%
of cases and metastasis in 14%.1 Although thought to be of low-grade malignancy, fatal courses
have been described4 and “analysis of the various series have demonstrated that tumors with a
solid growing pattern, nuclear atypia, DNA aneuploidy and high proliferative activity, generally
have a more aggressive behavior and a higher frequency of local recurrences and metastases.”3
Epithelial-Myoepithelial Carcinoma
of the Salivary Gland
Correspondence: Dr. Jose M. Carnate Jr.
Department of Pathology
College of Medicine, University of the Philippines Manila
547 Pedro Gil St., Ermita, Manila 1000
Philippines
Phone (632) 526 4450
Fax (632) 400 3638
Email: jmcjpath@yahoo.com
Reprints will not be available from the authors.
The authors declared that this represents original material
that is not being considered for publication or has not been
published or accepted for publication elsewhere, in full or in
part, in print or electronic media; that the manuscript has been
read and approved by the authors, that the requirements for
authorship have been met by the authors, and that the authors
believe that the manuscript represents honest work.
Disclosures: The authors signed disclosures that there are no
financial or other (including personal) relationships, intellectual
passion, political or religious beliefs, and institutional affiliations
that might lead to a conflict of interest. Philipp J Otolaryngol Head Neck Surg 2013; 28 (1): 36-37 c Philippine Society of Otolaryngology – Head and Neck Surgery, Inc.
Jose M. Carnate, Jr., MD1,
Jose Florencio F. Lapeña, Jr., MA, MD2
1Department of Pathology
College of Medicine
University of the Philippines Manila
Philippines
2Department of Otorhinolaryngology
College of Medicine – Philippine General Hospital
University of the Philippines Manila
Philippines
Figure 1. Tubular structures (single arrow) interspersed with pale to clear areas (double arrows)
(Hematoxylin and Eosin, 100x)
(Hematoxylin and Eosin, 100x)
PhiliPPine Journal of otolaryngology-head and neck Surgery Vol. 28 no. 1 January – June 2013
PhiliPPine Journal of otolaryngology-head and neck Surgery 37
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(Hematoxylin and Eosin, 400x)
Figures 2 and Figure 3. Tubular structures lined by a luminal layer of ductal epithelial cells
(single arrow) with an abluminal layer of myoepithelial cells with clear cytoplasm (double arrows)
(Hematoxylin and Eosin, 400x)
(Hematoxylin and Eosin, 400x)