Papillary carcinoma of the thyroid

Papillary carcinoma accounts for 80% of thyroid malignancies³.

Immunohistochemistry

cytokeratin	positive1
Cam5.2	9/92
high MW cytokeratin (LP34)	5/92
CK7	8/84
CK19	usually positive
CK20	0/84
CEA	4/92
S-100	7/92
thyroglobulin	positive1 (8/84)
Galectin-3	22/266, 20/205, 18/187
neuroendocrine markers	negative1
calcitonin	negative3
TTF-1	positive1 (8/84)
CA125	4/92

Molecular genetics

There are three mutations commonly present in papillary carcinomas of the thyroid and each associated with specific features⁸:

• BRAF mutations were associated with:

  •  older patient age
    
  • typical papillary appearance or the tall cell variant
    
  • a higher rate of extrathyroidal extension, and more advanced tumor stage at presentation.
• RET/PTC mutations:
  •  presented at younger age
    
  • have a predominantly typical papillary histology with frequent psammoma bodies
    
  • a high rate of lymph node metastases.
• RAS mutations:
  • are exclusively found in the follicular variant of papillary carcinoma
    
  • correlated with a low rate of lymph node metastases.

Differential diagnosis

• The follicular variant of papillary carcinoma from follicular carcinoma of the thyroid.

• There is a solid variant of papillary carcinoma with a differential diagnosis which includes poorly differentiated carcinoma, medullary carcinoma, anaplastic carcinoma and metastatic carcinoma to the thyroid. It has a slightly worse prognosis than the classical papillary type but much better than poorly differentiated carcinoma. It has the same nuclear morphology and immunohistochemical profile as the classical papillary type.³

References

¹ Diagnostic histopathology of tumors. Edited by CDM Fletcher. 2nd edition. Churchill Livingstone. Pages 975-6.

² Keen, C. E., Szakacs, S., Okon, E., Rubin, J. S., Bryant, B. M. CA125 and thyroglobulin staining in papillary carcinomas of thyroid and ovarian origin is not completely specific for site of origin Histopathology 1999;34:113-117

³ Nikiforov, Y. E., Erickson, L. A., Nikiforova, M. N., Caudill, C. M., Lloyd, R. V. Solid variant of papillary thyroid carcinoma: incidence, clinical- pathologic characteristics, molecular analysis, and biologic behavior. Am J Surg Pathol 2001;25:1478-1484.

⁴ Bejarano, P.A., Nikiforov, Y.E., Swenson, E.S. and Biddinger, P.W. Thyroid transcription factor-1, thyroglobulin, cytokeratin 7, and cytokeratin 20 in thyroid neoplasms. Appl Immunohistochem Mol Morphol 2000;8:189-94.

⁵ Cvejic, D., Savin, S., Paunovic, I., Tatic, S., Havelka, M. and Sinadinovic, J. Immunohistochemical localization of galectin-3 in malignant and benign human thyroid tissue. Anticancer Res 1998;18:2637-41.

⁶ Beesley, M.F. and McLaren, K.M. Cytokeratin 19 and galectin-3 immunohistochemistry in the differential diagnosis of solitary thyroid nodules. Histopathology 2002;41:236-43.

⁷ Fernandez, P.L., Merino, M.J., Gomez, M., Campo, E., Medina, T., Castronovo, V., Sanjuan, X., Cardesa, A., Liu, F.T. and Sobel, M.E. Galectin-3 and laminin expression in neoplastic and non-neoplastic thyroid tissue. J Pathol 1997;181:80-6.

⁸ Adeniran AJ, Zhu Z, Gandhi M, et al. Correlation between genetic alterations and microscopic features, clinical manifestations, and prognostic characteristics of thyroid papillary carcinomas. Am J Surg Pathol 2006; 30:216-22

This page last revised 9.4.2006.