ORAL AND MAXILLOFACIAL PATHOLOGY Editor: Alan R. Gould Myoepithelioma of the tongue Victoria Luo Kei Woo, DDS, a Francesca Angiero, MD, b and John E. Fantasia, DDS, c New Hyde Park, NY, and Milan, Italy LONG ISLAND JEWISH MEDICAL CENTER Soft tissue myoepitheliomas, in contrast to salivary gland myoepitheliomas, are benign neoplasms that typically occur in the soft tissues of the extremities. Both are characterized by a multilobular proliferation of polygonal to fusiform cells embedded in a variably myxoid to chondromyxoid matrix. A histologically similar lesion that has a marked predilection for the anterior dorsum of the tongue has been referred to as ectomesenchymal chondromyxoid tumor. The morphological and immunohistochemical resemblance of soft tissue myoepitheliomas to ectomesenchymal chondromyxoid tumors has led to the use of these designations interchangeably. We present a case of myoepithelioma of the tongue and review the literature, with emphasis on the differential diagnosis and histogenesis of this lesion and pertinent nosologic considerations. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2005;99:581-9) Myoepitheliomas have recently been recognized to occur in sites outside of the salivary gland apparatus, such as in soft tissues and the skin. 1,2 While such soft tissue myoepitheliomas more commonly arise in the subcutaneous or subfascial tissues of the extremities, localization to the head, neck, and trunk regions has also been observed. 3 These lesions have been described in patients over a wide age range with no apparent gender predilection, and clinically manifest as well- circumscribed, slow growing, painless nodules. 3 Histopathological examination reveals the presence of cords and sheets of round, polygonal, and fusiform cells arranged in a multilobular configuration. The lesional cells are present in a myxoid to chondromyxoid stroma that often alternates with foci of hyalinization. Immunohistochemically, myoepitheliomas are consis- tently positive for cytokeratins, vimentin, and S-100 protein and exhibit variable positivity for glial fibrillary acid protein (GFAP), epithelial membrane antigen (EMA), smooth muscle actin (SMA), and desmin. Immunostaining for keratins and/or EMA in conjunc- tion with staining for S-100 and/or myogenic markers is sufficient to support a diagnosis of myoepithelioma. 1,2 In 1995, Smith and colleagues 4 delineated a new myxoid tongue lesion that demonstrated characteristic microscopic features and an unusual predilection for the anterior dorsal tongue. They proposed that this lesion may represent a new clinicopathological entity with a unique cell of origin, and suggested the designation ectomesenchymal chondromyxoid tumor (ECT). Since their initial description of 19 cases, 4 9 additional cases of ECT have been reported in the literature 5-9 (Table I). However, the clinical and histological features of ECTs are virtually identical to those of myoepitheliomas. Moreover, these 2 lesions share similar immunohisto- chemical profiles that differ only by more consistent positivity for GFAP and less reliable positivity for cytokeratin in ECTs. This has prompted some authors to conclude that ECTs and myoepitheliomas may represent the same entity. 3 We present a case of myoepithelioma of the tongue and review the literature pertaining to both myoepithe- liomas and ECTs. CASE REPORT A 22-year-old female was referred for evaluation of a midline dorsal tongue lesion. The patient reported the lesion a Chief resident, Division of Oral Pathology, Department of Dental Medicine, Long Island Jewish Medical Center, New Hyde Park, NY. b Istituto di Anatomia Patologica, Universita ` degli Studi di Milano, Italy. c Chief, Division of Oral Pathology, Department of Dental Medicine, Long Island Jewish Medical Center, New Hyde Park, NY. Received for publication Nov 29, 2004; accepted for publication Dec 23, 2004. 1079-2104/$ - see front matter Ó 2005 Elsevier Inc. All rights reserved. doi:10.1016/j.tripleo.2004.12.016 581 Vol. 99 No. 5 May 2005