Adenoid cystic carcinoma of salivary gland

Histopathology

There are three characteristic patterns: cribriform, tubular and solid, most tumours being composed of a mix of these3. Tumour nuclei are typically small angulated and hyperchromatic; there is scanty cytoplasm.

Adenoid cystic carcinoma may undergo dedifferentiation to a high grade tumour with necrosis, a high mitotic rate and loss of the distinction between ductal and myoepithelial cells.

Immunohistochemistry

 

ductal epithelial cells

basaloid cells (myoepithelial differentiation)

cytokeratins

strong0

weak0

AE1/AE3

22/226

cytokeratin 7

20/202, 22/226

cytokeratin 8/18

53/532

cytokeratin 13

0/202

cytokeratin 14

33/332

cytokeratin 17

5/52

cytokeratin 19

28/282

cytokeratin 20

0/226

CEA

positive0

negative0

EMA

positive0

negative0

vimentin

negative0

positive0

S-100

negative0

positive0

actin

negative0

variable0

Calponin

negative0

positive0

CD43

 

positive, membranous4

CD117

positive1

     

Dedifferentiated adenoid cystic carcinoma:

 

 

differentiated ACC

dedifferentiated ACC

 
 

epithelium

myoepithelium

 

Pankeratin

4/47

4/4, focal7

4/47

AE1/AE3

2/27

2/2, focal7

2/27

Cam5.2

4/47

4/4, focal7

4/47

p63

 

7/87

1/8, focally in squamoid component7

Calponin

 

1/17

 

SMA

 

4/47

 

S100

6/7, focal7

1/77

6/77

CD117

6/67

 

6/67

Androgen receptor

 

 

0/67

Her-2

 

 

0/67

       

Cytogenetics

Loss of heterozygocity at 6q23-25 is common5.

Molecular genetics

There is overexpression of genes encoding basement membrane and extracellular matrix proteins5.

Differential diagnosis

Prognosis

Adenoid cystic carcinomas are slowly progressive with local recurrences and late metastases. Tumours with more than 30% solid pattern may have a worse prognosis3.

Management

Although adenoid cystic carcinomas are positive for CD117, tyrosine kinase receptor inhibitor has not been found to be beneficial4.

References

0Diagnostic histopathology of tumors. Edited by CDM Fletcher. 2nd edition. Churchill Livingstone. Page 269.

1 Berman, J., O'Leary, T. J. Gastrointestinal stromal tumor workshop Human Pathol 2001; 32:578-582.

2 Chu, P. G. and L. M. Weiss (2002). "Keratin expression in human tissues and neoplasms." Histopathology 40(5): 403-39. (Summary data from multiple papers)

3 Perez-Ordonez B. Selected topics in salivary gland tumour pathology. Current Diagnostic Pathology2003;9:355-365.

4 Hotte SJ, Winquist EW, Lamont E, et al. Imatinib mesylate in patients with adenoid cystic cancers of the salivary glands expressing c-kit: a Princess Margaret Hospital phase II consortium study. J Clin Oncol 2005; 23:585-90

5 Cheuk W,Chan JK. Advances in salivary gland pathology. Histopathology 2007; 51:1-20

6 Meer S,Altini M. CK7+/CK20- immunoexpression profile is typical of salivary gland neoplasia. Histopathology 2007; 51:26-32

7 Seethala RR, Hunt JL, Baloch ZW, et al. Adenoid cystic carcinoma with high-grade transformation: a report of 11 cases and a review of the literature. Am J Surg Pathol 2007; 31:1683-94

This page last revised 30.12.2007.