Mucoepidermoid carcinoma (MEC)[1] is the most common type of minor salivary gland malignancy in adults. Mucoepidermoid carcinoma can also be found in other organs, such as bronchi, lacrimal sac,[2] and thyroid gland.
Mucicarmine staining is one stain used by pathologist for detection.[3]
Presents as painless, slow-growing mass that is firm or hard. Most appear clinically as mixed tumors. Usually occurs at 30–50 years of age. More predilection towards female sex.
Mucoepidermoid carcinomas of the salivary and bronchial glands are characterized by a recurrent t(11;19)(q21;p13) chromosomal translocation resulting in a MECT1-MAML2 fusion gene.[4] The CREB-binding domain of the CREB coactivator MECT1 (also known as CRTC1, TORC1 or WAMTP1) is fused to the transactivation domain of the Notch coactivator MAML2.[5]
In terms of diagnosis we find that histological staining, radiological imaging and molecular diagnostic features all play a role in the evaluation[1]
This tumor is not encapsulated and is characterized by squamous cells, mucus-secreting cells, and intermediate cells.[7]
a-d)Immunohistochemistry for CD44 in Mucoepidermoid carcinomas
Histopathologic image of mucoepidermoid carcinoma of the major salivary gland. H & E stain
Histopathologic image of mucoepidermoid carcinoma of the major salivary gland. The same lesion as shown in a filename "Mucoepidermoid carcinoma (2) HE stain.jpg". H & E stain
Histopathologic image of mucoepidermoid carcinoma. Postoperative recurrence of the submandibular tumor. Alcian blue-PAS stain
Surgery is the recommended treatment for localised resectable disease.[8]
When the tumour is incompletely resected (positive margins) post-operative radiotherapy gives local control comparable to a complete resection (clear margins).[9]
Sometimes when surgery is not possible due to extent of disease or if a patient is too frail for surgery, or declines surgery, palliative radiotherapy may be helpful. There has been a report of a case where low dose radiotherapy achieve disease response and control for more than 4 years.[10]
In patients with metastatic disease, chemotherapy response tends to be low (27% partial response rate) and short lived.[11]
Generally, there is a good prognosis for low-grade tumors, and a poor prognosis for high-grade tumors, however recent research have found reoccurring low grade tumors also have a poor prognosis.[12]
Occurs in adults, with peak incidence from 20–40 years of age. A causal link with cytomegalovirus (CMV) has been strongly implicated in a 2011 research.[13]
Relative incidence of parotid tumors, showing mucoepidermoid carcinoma at top right.[14]
Relative incidence of submandibular tumors, showing mucoepidermoid carcinoma at top right.[14]
↑ 1.01.1Kalhor N, Moran CA (March 2018). "Pulmonary mucoepidermoid carcinoma: diagnosis and treatment". Expert Review of Respiratory Medicine. 12 (3): 249–255. doi:10.1080/17476348.2018.1428563. PMID29338644.
↑Williams JD, Agrawal A, Wakely PE (February 2003). "Mucoepidermoid carcinoma of the lacrimal sac". Annals of Diagnostic Pathology. 7 (1): 31–34. doi:10.1053/adpa.2003.50005. PMID12616472.
↑Chiosea SI, Dacic S, Nikiforova MN, Seethala RR (August 2012). "Prospective testing of mucoepidermoid carcinoma for the MAML2 translocation: clinical implications". The Laryngoscope. 122 (8): 1690–1694. doi:10.1002/lary.22419. PMID22833306.
↑Behboudi A, Enlund F, Winnes M, Andrén Y, Nordkvist A, Leivo I, et al. (May 2006). "Molecular classification of mucoepidermoid carcinomas-prognostic significance of the MECT1-MAML2 fusion oncogene". Genes, Chromosomes & Cancer. 45 (5): 470–481. doi:10.1002/gcc.20306. PMID16444749.
↑Chenevert J, Barnes LE, Chiosea SI (February 2011). "Mucoepidermoid carcinoma: a five-decade journey". Virchows Archiv. 458 (2): 133–140. doi:10.1007/s00428-011-1040-y. PMID21243374.
↑Verma J, Teh BS, Paulino AC (December 2011). "Characteristics and outcome of radiation and chemotherapy-related mucoepidermoid carcinoma of the salivary glands". Pediatric Blood & Cancer. 57 (7): 1137–1141. doi:10.1002/pbc.22978. PMID21280198.
↑Hosokawa Y, Shirato H, Kagei K, Hashimoto S, Nishioka T, Tei K, et al. (January 1999). "Role of radiotherapy for mucoepidermoid carcinoma of salivary gland". Oral Oncology. 35 (1): 105–111. doi:10.1016/s1368-8375(98)00053-0. PMID10211318.
↑Melnick M, Sedghizadeh PP, Allen CM, Jaskoll T (February 2012). "Human cytomegalovirus and mucoepidermoid carcinoma of salivary glands: cell-specific localization of active viral and oncogenic signaling proteins is confirmatory of a causal relationship". Experimental and Molecular Pathology. 92 (1): 118–125. doi:10.1016/j.yexmp.2011.10.011. PMID22101257.
↑ 14.014.1Steve C Lee, MD, PhD. "Salivary Gland Neoplasms". Medscape. Archived from the original on 2022-09-07. Retrieved 2022-09-08.{{cite web}}: CS1 maint: multiple names: authors list (link) Updated: Jan 13, 2021}} Diagrams by Mikael Häggström, MD