Laryngeal Primary Myoepithelial Carcinoma: Case Report and a Systematic Review of Literature

Introduction

Myoepithelial carcinoma (MEC) can be described as malignant myoepithelioma was first reported by Stromeyer ¹ in 1975. It accounts for less than 1% among the salivary glands tumors. MEC arising from the pharynx and larynx is rarer. Ibrahim ² described the first patient with “MEC of the larynx.” Since then, a limited number of patients with MEC of larynx and pharynx are reported.^{3 -9} In this study, we describe a case with MEC of laryngeal primary myoepithelial carcinoma and other 10 cases for literature review.^{2 -9} Clinical data of these 11 cases were analyzed to investigate the biological behavior, diagnosis, treatment, and prognosis of MEC of the larynx.

Case Report

The 60-year-old male patient suffered from hoarseness for six months and throat pain for one month. The patient had smoking history for 15 years with 20 cigarettes or more a day and no previous history of chronic disease. Laryngoscopy showed a cauliflower-like neoplasm at the right ventricle of the larynx (Figure 1A). Computed tomography (CT) of the neck showed irregular soft tissues in the right wall adjacent to the glottis (Figure 1B). Biopsy was performed, and the disease was pathologically diagnosed as myoepithelial carcinoma by histopathology and immunohistochemical staining as follows (Figure 2): S100(+), EMA(+), Vim(+), CK(–), P63(+,less), P40(–), CK5/6(–), SMa(–), Des(–), Myo-D1(–), and Ki67(+,30%). Preoperative neck ultrasonography showed multiple lymph nodes at the bilateral neck (diameter < 1 cm). Liver ultrasonography and chest film showed no abnormalities. The patient underwent tracheotomy under general anesthesia + right partial laryngectomy + laryngoplasty, and received radiotherapy (60Gy) at postoperative 10d. The tracheal tube was smoothly removed after one month. The patient underwent laryngoscopy, ultrasonography and CT at 15-month follow-up, all of which showed no tumor recurrence and metastasis.OPEN IN VIEWER

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Figure 2.

Spindle tumor cells arranged in bundles or micro-cysts with visible mitotic in microscopic evaluation (H&E, ×200) (A) and positive immune staining with EMA (İHC, ×200) (B), S100 (İHC, ×200) (C), Vim (İHC, ×200) (D), and P63 (İHC, ×400) (E).

Discussion

MEC is an uncommon disease which originated from myoepithelial cells or epithelial cells with ducts having a multi-directional differentiation potential. MEC of the larynx and pharynx is much more rarely, as far as we know, only 10 cases previously reported in domestic and foreign publications,^{2 -9} Table 1 provides an overview of total 11 patients.

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Table 1.

Over review of 11 patients with myoepithelial carcinoma of larynx and pharynx.

Reference	Age (years)	Gender	Manifestations	Primary Site	TNM Staging	Treatment	Follow-up (months)	Outcomes
Author	60	M	Hoarseness	Supraglottis	T2N0M0	Hemilaryngectomy	15	No recurrence
			Larynx pain			Radiotherapy (60Gy)
Ibrahim	71	M	Hoarseness, acataposis	Larynx and pharynx	T4N2M1	Radiotherapy (70Gy)	3	Death
						Chemotherapy (PF program)
Ganly	70	M	Hoarseness, dyspnea	Supraglottis	T3N0M0	Radiotherapy (70Gy)	33	No recurrence
Ganly	76	M	Acataposis	Supraglottis	T2N1M0	Laryngectomy	194	Death (other diseases)
			Pharynx and larynx pain			Ipsilateral neck disserction
GH Yu	78	M	Hoarseness and bloody sputum	Right vocal cord	T2N0M0	Right hemilaryngectomy	11	No recurrence
YJ Nao	61	M	Hoarseness,	Bilateral vocal cord	T3N0M0	Laryngectomy	25	Death
			Dyspnea			Radiotherapy (60Gy)
YK Ma	64	M	Hoarseness	Anterior commissure	T2N0M0	Anterior hemilaryngectomy	6	No recurrence
			Abnormal sensation of throat	Right vocal cord		Radiotherapy (60Gy)
						Chemotherapy (PF program)
YP He	21	M	Hoarseness larynx discomfort	Left vocal cord	T1N0M0	Local removal of tumor	42	No recurrence
						Hemilarygnectomy
M Guan	48	M	Swallowing difficulty	Left hypopharynx	T2N0M0	Removal of the tumor	17	No recurrence
						Ipsilateral neck dissection
QG Chen	35	F	Hoarseness	Left hypopharynx	T2N0M0	Removal of the tumor	132	No recurrence
QG Chen	56	F	Pharynx discomfort	Hypopharynx and Larynx	T4N1M0	Total laryngectomy and glossectomy	42	No recurrence
						Bilateral neck dissection

Among the cases, MEC of the larynx and pharynx seemed more prevalent in male (9 of 11, 81.8%). The age ranged from 21 to 78 years, patients over 60-year-old would be at higher risk (7 of 11, 63.6%). The primary site originated from the superior glottis, vocal cords, hypopharynx, hypopharynx involving larynx, and larynx involving pharynx in case 4, 3, 2, 1, and 1, respectively. The symptoms mainly manifested as hoarseness as well as pharyngeal and laryngeal discomfort at the early stage. Besides, hoarseness, acataposis, and dyspnea would occur at the late stage. Three cases were accompanied by lymphatic metastasis and one by distant metastasis (hepatic metastasis).

Currently, MEC is typically treated by surgery. The resection range should be expanded as much as possible after considering local anatomy and function. There should be sufficient secure boundary, and intraoperative frozen sectioning should be performed, if necessary, to determine the secure edge for tumor incision. In this study, 9 out of 11 patients (81.8%) underwent surgery, different operational treatments are described in Table 1, of which two cases were preoperatively confirmed with lymphatic metastasis and underwent functional neck dissection, one case underwent preventive neck dissection because the disease was located at hypopharynx, while the other cases did not receive preventive neck dissection and did not suffer from lymphatic metastasis during the postoperative follow-up. Thus, we believe that preventive neck dissection is unnecessary in patients with CN0 MEC of the pharynx and larynx.

Among all 11 patients, two patients did not accept operation, one of which suffering from distant metastasis at admission was given radio-chemotherapy and died after 3 months, another was given radiotherapy alone because of his refusal to surgery and did not show recurrence after 33 months. Moreover, three cases received postoperative radiotherapy, of which one died during a 25-month follow-up due to recurrence, and other two did not show recurrence during the follow-up. Thus, we believe that radiotherapy has a definite curative effect on MEC of the pharynx and larynx, and the necessity of postoperative radiotherapy should be determined according to the tumor staging.

Since MEC of the pharynx and larynx is very rare, its biological behavior remains unknown. In this study, 8 out of 11 patients (72.7%) did not show recurrence while three cases were reported died during follow-up (one with distant metastasis at admission died after diagnosis for 3 months, one died because of cardiovascular disease after 194-month follow-up and one died postoperatively of recurrence after 25 months). Therefore, MEC of the pharynx and larynx may not be highly malignant.

MEC has a high blood metastasis rate, which was reported to be 26.3–47%. ¹¹ Thus, patients with MEC of the head and neck generally undergo preoperative chest film, liver B-ultrasound, and nuclear bone scan, if necessary, to exclude the possibility of distant metastasis.

Conclusion

MEC of the pharynx and larynx is a rare malignant tumor without characteristic manifestations due to diverse cellular morphologies. Its pathological features are not directly associated with the outcomes, leading to numerous controversies in diagnosis and treatment. We believe that surgical resection is the main treatment method for such invasive diseases with high recurrence and metastatic potential. For most cases, we should strive to achieve extensive resection with clean margin, which is closely associated with prognosis and survival rate of the disease. Meanwhile, we should determine the necessity for auxiliary radiotherapy and chemotherapy according to tumor staging and clean margin. Although this is a retrospective analysis of a small sample size, we believe that it can enrich the knowledge of MEC of the pharynx and larynx.