| Abstract|| |
Myoepithelial carcinomas represent <1% of salivary gland tumors. Tongue is a rare site of occurrence. We present a case of a 30 year old female with myoepithelial carcinoma seen over dorsum of tongue with predominantly spindle cell morphology with clear cytoplasm and mitotic count of 6–7/10 hpf. We need to differentiate it from a spindle cell squamous cell carcinoma which can be seen at this location, i.e., tongue. In our case, there was no connection of the tumor with overlying squamous epithelium.
Keywords: Myoepithelial tumor, salivary gland neoplasm, tongue neoplasms
|How to cite this article:|
Sharma A, Gogoi P, Arora VK. Myoepithelial carcinoma of the tongue- spindle cell morphology with high mitosis: A case report and review of literature. Indian J Pathol Microbiol 2017;60:560-1
|How to cite this URL:|
Sharma A, Gogoi P, Arora VK. Myoepithelial carcinoma of the tongue- spindle cell morphology with high mitosis: A case report and review of literature. Indian J Pathol Microbiol [serial online] 2017 [cited 2020 May 26];60:560-1. Available from: http://www.ijpmonline.org/text.asp?2017/60/4/560/222991
| Introduction|| |
Myoepithelial carcinomas represent <1% of salivary gland tumors. Parotid gland and minor salivary glands of the palate are the usual sites of occurrence. Tongue is a rare site of occurrence. We present a case of a 30-year-old female with myoepithelial carcinoma over dorsum of tongue along with a review of literature.
| Case Report|| |
A 30-year-old female presented to the outpatient department with complaints of swelling over dorsum of tongue for 3 months. Fine-needle aspiration cytology revealed the presence of a salivary gland tumor. An excision biopsy was performed and tissue was sent for histopathological examination.
On gross examination, we received a single gray-white tissue piece measuring 1.9 cm × 1.7 cm × 1.8 cm with tumor measuring 1.7 cm × 1.5 cm × 1.5cm. Microscopy showed the presence of an unencapsulated tumor with infiltrative margins arranged in the form of lobules and nests with numerous fine vessels seen separating the tumor cells. Overlying stratified squamous epithelium was seen separately from the tumor. Cells were spindle shaped with moderate amount of clear cytoplasm, round to oval moderately pleomorphic nucleus with fine chromatin and conspicuous nucleoli [Figure 1]. Mitotic count was 6–7/10 hpf. On immunohistochemistry, tumor cells were positive for S-100 and vimentin, while they were negative for cytokeratin, epithelial membrane antigen and calponin. Ki-67 index was >10% [Figure 2]. Based on the above morphological and immunohistochemical features, a diagnosis of myoepithelial carcinoma was given.
|Figure 1: Myoepithelial carcinoma-tongue: microscopic findings. (a) Unencapsulated tumor with infiltrative margins and overlying stratified squamous epithelium (H and E, ×40). (b) Tumor arranged in the form of lobules and nests (H and E, ×40). (c) Numerous fine vessels seen separating the nests of tumor cells (H and E, ×100). (d) Spindle shaped cells with moderate amount of clear cytoplasm and high mitosis (H and E, ×400)|
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|Figure 2: Myoepithelial carcinoma-tongue: immunohistochemistry. (a) Tumor cells positive for S-100 (×200). (b) Tumor cells positive for vimentin (×200). (c) Tumor cells with Ki-67 labeling index >10% (×200). (d) Tumor cells negative for cytokeratin (×100)|
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| Discussion|| |
Myoepithelial carcinoma of salivary gland usually has a multilobulated appearance, along with areas of necrosis and infiltrative margins. Our case had a multilobulated pattern with infiltrative margins. However, no area of necrosis was observed. Myoepithelial carcinoma is composed of varying proportions of spindled, epithelioid, plasmacytoid, and clear cells set against a mucoid or myxoid background. Our case had predominant spindle cell morphology without a myxoid background. Mitotic count was 6–7/10 hpf which is usually seen in high-grade tumors. The immunohistochemistry assessment of the Ki-67 labeling index is helpful in the differential diagnosis between myoepithelioma (<10%) and myoepithelial carcinoma (>10%). Calponin, S-100, vimentin, and smooth muscle actin have been reported to be important in the diagnosis of myoepithelial carcinoma., In a review of fifty cases of myoepithelial carcinoma, vimentin was positive in 100% cases, calponin in 98% cases, S-100 in 82% cases, and smooth muscle actin in 35% cases. Our case was positive for S-100 and vimentin. However, calponin was negative. In view of the morphological findings, a diagnosis of myoepithelial carcinoma was given in our case.
In the reviewed literature, we found only five cases of myoepithelial carcinoma of the tongue.,,, Of the fifty cases of myoepithelial carcinoma reviewed by Kane et al., only two were seen in the tongue. Both cases were ≥2 cm in greatest dimension. Our case was <2 cm in greatest dimension. Of 21 cases of myoepithelial carcinoma reviewed by Hungermann et al., only one was present over the tongue. It had a plasmacytoid morphology and had a mitotic count <1/10 hpf. Our case had a spindle-cell morphology and mitotic count of 6–7/10 hpf. Of seven cases of myoepithelial carcinoma reviewed by Yang et al., only one was present over the tongue. Park et al. reported a case of myoepithelial carcinoma over the tongue which measured 4.5 cm × 3 cm and had clear cytoplasm. Our case also had clear cytoplasm. Molecular analysis might be helpful in some cases. 6q deletion has been seen in one of the cases.
| Conclusion|| |
Our case is a 30 year old female with myoepithelial carcinoma seen over dorsum of tongue with predominantly spindle cell morphology with clear cytoplasm and mitotic count of 6–7/10 hpf. We need to differentiate it from a spindle cell squamous cell carcinoma which can be seen at this location, i.e., tongue. In our case, there was no connection of the tumor with overlying squamous epithelium. Moreover, immunohistochemistry was negative for pan-cytokeratin and epithelial membrane antigen.
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The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
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Conflicts of interest
There are no conflicts of interest.
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Dr. Vinod Kumar Arora
Department of Pathology, University College of Medical Sciences and Guru Teg Bahadur Hospital, New Delhi
Source of Support: None, Conflict of Interest: None
[Figure 1], [Figure 2]