1. KCP 794
인하대병원 전공의 최창환

2. Clinical history M/49 6개월 전부터 만져지는 오른쪽 귀 앞부위의 종괴 경부 컴퓨터 단층촬영
오른쪽 귀밑샘의 얕은엽에 4.1cm의 경계가 좋은 불균질하게 조영증강되는 종괴
세침흡인 검사 후 절제술 시행

3. Well-marginated heterogeneous enhancing mass (4.1x3.6x2.8cm)
Benign salivary gland tumor such as pleomorphic adenoma, more likely
R/O low grade malignant salivary gland tumor

6. Cytologic findings Cellular smear
Isolated and aggregates of bland-looking myoepithelial cells in myxoid background
Scattered clusters of atypical epithelial cells
large hyperchromatic nuclei, prominent nucleoli and irregular nuclear membrane
abundant cytoplasm with focal finely granular/vacuolated cytoplasm

7. Differential diagnosis
Malignant salivary gland tumor
Carcinoma ex pleomorphic adenoma
Adenocarcinoma, NOS
Salivary duct carcinoma
Acinic cell carcinoma
Mucoepidermoid carcinoma

8. Cytologic diagnosis
Parotid gland, right, FNA: Carcinoma ex pleomorphic adenoma

13. Histologic diagnosis NONINVASIVE CARCINOMA EX PLEOMORPHIC ADENOMA
Parotid gland, right near total parotidectomy:
NONINVASIVE CARCINOMA EX PLEOMORPHIC ADENOMA
with 1) Carcinoma component: ADENOCARCINOMA, not otherwise specified
2) Tumor size: 4.0x3.3cm
3) Carcinoma size: 2.1x1.6cm
4) Confinement to the capsule without invasion

14. Carcinoma ex pleomorphic adenoma
Adenocarcinoma, NOS
Salivary duct carcinoma
Mucoepidermoid carcinoma
Adenoid cystic carcinoma
Acinic cell carcinoma
Clear cell carcinoma
Myoepithelial carcinoma
Carcinoma component
>50% of mass in 80% cases (Olsen et al)
>66% of mass in 42% cases (Zbaren et al)
Any form of carcinoma

15. Diagnostic pitfall Sampling error Benign component alone
Carcinomatous element alone

16. Diagnostic pitfall Nigam et al. 2004 Group I Group II
Unequivocal malignant cells
Benign epithelial and stromal components of pleomorphic adenoma
Group II
Mild to moderate degrees of pleomorphism
Absence of unequivocal malignant cell
Benign epithelial and stromal components
Sampling error is an important cause of diagnostic pitfalls

17. Identifying CXPA by FNAC
4/14 (28%) (Nouraei et al)
13/26 (50%) (Klijanienko et al)
7/16 (43%) (Zbaren et al)
Most false-negative finding
Pleomorphic adenoma
Sampling error > misinterpretation
Small carcinoma component
Other malignancy
Acinic cell carcinoma (Verma et al)

18. Diagnostic clue Background benign component Carcinomatous element
Fibrillary/chondromyxoid background matrix
Ovoid/plasmacytoid myoepithelial cells
Uniform epithelial cells
Carcinomatous element
Any form of carcinoma