Outline

After reading this post you will learn the following about Mucoepidermoid Carcinoma:-

  • Introduction
  • Clinical Features
  • Histopathologic Features
  • Variants of Tumor
  • Treatment & Prognosis

Introduction

  • MUCOEPIDERMOID CARCINOMA – As the name implies
    • Mucoepidermoid:- Composed of-
      • Mucus-secreting Cells
      • Epidermoid-type Cells
    • Carcinoma means malignant epithelial tumor
    • The mucus and epidermoid cells are in varying proportions
    • Columnar and clear cells are also seen
    • Often demonstrate prominent cystic growth
  • Most common malignant neoplasm in the major and minor salivary glands
  • Accounts for 5% of all salivary gland tumors
  • Most common site – Parotid Gland
  • Intraorally, most common site is Palate

Clinical Features

  • SEX – Slight female predilection
  • AGE – Any age but occurs primarily in the third or fifth decades of life, with an average age of 47 years
  • Most common malignant salivary gland tumor of children
    • Pathogenesis uncertain, although radiation exposure may be one risk factor
    • Low Grade Tumor
    • Slow growing
    • Painless mass
    • Rarely exceeds 5 cm in diameter
    • Not completely encapsulated
    • Often contains cyst filled with viscid mucoid material
    • Intraoral Sites – Palate (most common), buccal mucosa, tongue & retromolar areas
  • High Grade Tumor
    • Rapidly growing swelling
    • Pain is an early symptom
    • Facial nerve paralysis frequent in parotid tumors
    • Other Complaints – Trismus, difficulty in swallowing, drainage from ear, numbness of adjacent areas, ulceration (especially in tumors involving minor salivary glands)
    • Not encapsulated, tends to infiltrate surrounding tissue, also many cases metastasize to regional lymph nodes
    • Distant Metastasis Common – Lung, bone, brain & subcutaneous tissue

Histopathologic Features :-

  • Mucoepidermoid Carcinoma is composed of:
    • Mucus-producing Cells
    • Squamous (Epidermoid) Cells
    • Intermediate Cells – More important in recognizing mucoepidermoid carcinoma. Highly prolific, basaloid cells. Thought to be a progenitor of both mucous and epidermoid cells.

Table Showing Features Of 3 Cell Types Seen In Mucoepidermoid Carcinoma:-

  • Some tumors also show variable numbers of clear cells.
  • Epidermoid, mucous & intermediate cells line cystic space or form solid masses or cords.
  • Epidermoid & mucous cells may be arranged in glandular pattern.
  • Cysts may rupture & release mucin. This mucin may pool in the connective tissue and evoke an inflammatory reaction.
  • Traditionally, mucoepidermoid carcinomas have been categorized into one of three histopathologic grades (LOW/INTERMEDIATE/HIGH) based on:
  • Amount of cyst formation.
  • Degree of cytologic atypia.
  • Relative numbers of mucous, epidermoid, and intermediate cells.

TABLE SHOWING CRITERIA FOR CATEGORIZING MUCOEPIDERMOID CARCINOMA INTO 3 HISTOPATHOLOGIC GRADES – LOW, INTERMEDIATE & HIGH GRADE TUMOR

References :-

  • Shafer’s Textbook Of Oral Pathology
  • Shear – Cysts Of The Oral & Maxillofacial Regions
  • Neville – Oral & Maxillofacial Pathology
  • Image – Wikipedia & Wikimedia Commons

Variants Of Tumor

  • Sclerosing Mucoepidermoid Carcinoma
  • Intraosseous Mucoepidermoid Carcinoma

Treatment & Prognosis

  • Low & intermediate-grade mucoepidermoid carcinomas of the parotid gland – Conservative excision with preservation of facial nerve, if possible, recommended
  • Affected submandibular gland – Removed entirely
  • If patient shows clinical evidence of cervical node metastasis/ T3 lesion – Radical neck dissection is performed
  • Treatment for the minor glands – Primarily surgical
  • For high grade tumors – Post-op Radiation & chemotherapy