《Slide 36.》Pleomorphic adenoma (mixed tumor),
Salivary gland

A. Brief Descriptions：

  1. The most common tumor, according for 60 percent to 70 percent of all parotid tumors and for 40 percent to 70 percent of tumors in other glands.

  2. Benign tumor; consisting of cells with epithelial(luminal) and myoepithelial (abluminal) differentiation, and variable amounts of characteristic stroma.

  3. Have also been called mixed tumor.

B. Gross Findings：

      Rubbery, resilient mass with a bosselated surface.

C. Micro Findings：

  1. Biphasic appearance resulting from the admixture or epithelial & stroma.

  2. Epithelial component

    • Glandular (ductal) with foci of squamous metaplasia.

    • Inner ductal lining cells from flatten to columnar.

    • Outer myoepithelial cells from cuboidal, flattened, clear spindle shaped or hyaline, sometimes proliferated to form thick, ill-defined sheaths around ducts, or become swollen & hydropic to cartilage-like cells (chondroid change).

    • Lumen may contain clear to eosinophilic fluid.

  3. Stroma：Nonspecific fibromyxoid appearance with abundant elastic tissue (myxoid change), with clear-cut cartilaginous, myxochondroid, or calcification.

D. Others:

  1. Most common neoplasm of the salivary glands especially parotid gland, with slow growth.

  2. Proliferation of myoepithelial cells with pleomorphic appearance.

  3. Some mimic epithelial component while others mimic stroma component (cartilage).

E. Reference：

     Robbins Pathologic Basis of Disease, 6th ed.  P.770-771.

　

 

 

 

【 Fig. 36-1 (2X)】A relatively well defined tumor seen in this field.

　

 

 

【 Fig. 36-2 (1X)】A relatively well defined tumor seen in this field.

　

 

 

【 Fig. 36-3 (4X)】Biphasic appearance resulting from the admixture or epithelial & stroma.

　

　

 

【 Fig. 36-4 (10X)】Biphasic appearance resulting from the admixture or epithelial & stroma.

　

　

 

【 Fig. 36-5 (20X)】Epithelial component.

　

 

 

【 Fig. 36-6 (20X)】Epithelial component.

　

 

 

【 Fig. 36-7 (20X)】Epithelial component.

　

 

 

【 Fig. 36-8 (40X)】Glandular (ductal) component.