The Role of CD56 in distinction of PTC from other thyroid neoplasms

Objective: Thyroid nodules which are common in population consist of mostly benign nodules and lessmalignant neoplasms. Differentiating malignant nodules from each other arises a drastic problem in making acorrect diagnosis Thus,this study was done to investigate the role of CD56 and its specificity and sensitivity indifferent types of thyroid neoplasms especially papillary carcinoma.Methods: 73 paraffin embedded-blocks of thyroid massses (nodules) were studied for CD56immunohistologically from Imam Khomeini hospital ,Sari,Mazandaran.The 4-scaled semiquantitative method(0-3) was applied to estimate CD56 expression in tumor cells; less than 10% (0) or negative staining, 10-33%(1), 33-66% (2), more than 66% (3).Results: In this study 24.7% were male and 75.3% were female. 13.7% ,68.5 % and 17.8% of patients were lessthan 20, between 20- 50,and over 50 years old respectively.Simultaneously 50(68.5%) patients had both rightand left lobes nodules.12(16.4%) ,6(8.2%)and 1(1.4%) patients had nodules in right and left lobes and isthmusrespectively.Consequently, 4 (5.5%)patients showed left and right lobes ,and ithsmus nodules simultaneousely.There was no statistically significant difference between the sexes and ages and also anatomical regions inpatients with and without PTC. 30 out of the 73 patients had papillary carcinoma(PTC) which 4 out of themexpressed CD56 while 37 out of 43(86%) patients who had non-PTC showed positive results forCD56.Sensivity and specificity of negative result of CD56,positive predictive value(PPV) and negativepredictive value(NPV) in the diagnosis of papillary carcinoma were 86.6%,86%,81.2% and 86.3% respectively.Conclusion: Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) andoverall accuracy (OA) of negative result of CD56 in the diagnosis of PTC were 86.6%, 86.04%, 81.25%,90.24% and 86.3% respectively. This study showed that CD56 was a valuable sensitive and specific marker indifferentiating PTC from other thyroid tumors.

Keywords:

Papillary thyroid carcinoma , Other thyroid masses , CD56