“Ectomesenchymal chondromyxoid tumor” of the anterior tongue was first described by Smith et al
in 1995 following review of all myxoid, chondromyxoid, and myoepithelial tongue lesions from the files of the Armed Forces Institute of Pathology in a 24-year period. Of the total cases evaluated, 19 cases did not fulfill the diagnostic criteria for any other intraoral soft tissue chondromyxoid lesion and had similar unique clinicopathological and immunohistochemical features.[1
] Following the first report by Smith et al
, only 21 cases have been reported in the past 15 years taking the total number of cases to 40 in literature till date . The reason for the limited reported cases of ECMT is probably because it being misinterpreted as other similar chondromyxoid lesions like focal mucinosis, soft tissue myxoma, ossifying fibromyxoid tumor, chondroid choristoma, nerve sheath myxoma, myoepithelioma, pleomorphic adenoma and mucocele.
Clinically, ECMT presents as a slow growing asymptomatic swelling exclusively seen on the anterior dorsum of the tongue, however, two cases presenting on the posterior tongue have been documented.[4
] In addition, a case of ECMT on the hard palate has been reported but due to lack of appropriate documentation to support its diagnosis has been a subject of controversy.[10
] The size of the lesion varies from 0.3 to 2.0 cm. Age of affected patients ranges from 9 to 78 years of age, with a mean age of 39 years. Both males and females are affected equally .[1
Macroscopic examination of ECMT reveals a submucosal, pale gray to tan to yellow rubbery nodule. Cut surface usually demonstrates a well-circumscribed mass that may have a gelatinous consistency and show foci of hemorrhage. Histopathologically, the lesion is unencapsulated but well circumscribed owing to the compression of the fibrous tissue and the muscle fibers at the periphery of the lesion. The lesional cells are arranged in cords, strands, sheets in a myxoid to chondromyxoid background. Cellular morphology ranges from round, oval, polygonal to spindle shaped. The nuclei are generally rather small and uniform, although some lesions may have foci of nuclear atypia, characterized by variation in nuclear size, evidence of nuclear hyperchromatism, or the presence of binucleated or multinucleated cells and pseudoinclusions.[1
] Some authors speculate that these areas of suspected atypia could in fact be associated with secondary inflammatory stimuli or aging of the tumors.[2
] Mitotic figures are rare and necrosis is virtually absent. Few muscle fibers can be focally infiltrated by tumor cells, but does not seem to represent evidence of aggressive behavior.[3
] Focal areas of inflammation, hemorrhage, few small-caliber blood vessels and partitioning of the tumor lobules by thin bands of fibrous connective tissue can be found.
To aid in the diagnosis of ECMT, Smith et al
. conducted immunohistochemistry on his 19 cases, which showed strong positivity for GFAP (18 of 19 cases), variably reactive to CD-57/Leu-7 (8 of 9 cases were positive), nonreactive to strongly reactive for cytokeratin (AE1/AE3), positive occasionally for S-100, and negative for Epithelial membrane antigen (EMA) and desmin.[1
] Following this many reported cases have used similar immunoprofile for the diagnosis of ECMT with a variable degree of expression of these markers .[16
Various histogeneic concepts have been suggested for the development of ECMT. One such and most accepted hypothesis is it arises directly from neural cells in the tongue or from primitive mesenchymal cells that undergo neural differentiation during tumorigenesis.[1
] Others believe it to be either of myoepithelial or myogenic origin.[8
] These probable histogenic concepts could be the reason for the variable expression of immunomarkers .[1
Treatment of choice of ECMT is conservative surgical excision. But there have been two cases where recurrence has been reported, however were successfully managed in the second surgical intervention.[1
] Although all available evidence reinforces the benign nature of ECT, the small number of recurrent cases and the histopathological evidence of foci of pleomorphic hyperchromatic cells, sporadic mitotic figures and muscle infiltration suggest the importance of regular follow-up of patients after treatment.