General Data

� Age : 39 y/o

� Gender : female

� Marriage : 已婚

Chief Complaint

� A palpable mass over right cheek which was found for 1 year

Present Illness

� A palpable mass about 1.5 x 1.5 cm was found in 1 year ago.

� The mass become bigger recently

� Intermittent neck pain and stiffness

� No pain, no tenderness, no wound, no numbness

Past history

� T-colon cancer, s/p segmental resection at 新光, chemotherapy in 北醫 about 4 years ago

� DM (-)

� Hypertension (-)

� Allergy (-)

Lab data

� WBC : 6.89 10^3/u

� RBC : 4.47 10^6/uL

� Na : 133 mEq/L

� K : 3.8 mEq/L

� There is an ill-defined round mass, about 2.0x1.9x1.5 cm in size, with inhomogeneous parenchymal enhancement in the anterior superficial lobe of right parotid gland.

D/D from Image

� Plemorphic adenoma

� Warthin’s tumor

� Mucoepidermoid carcinoma

� Adenoid cystic carcinoma

� Squamous cell carcinoma

� Metastasis

D/D from parotid gland

� LocationThe lobe of Parotid gland

Parapharyngeal area, tonsillar area, Cervical lymph node

� SymptomsFacial nerve paralysis

� AgeBenign tumor → 40 ~ 60 y/o

Malignancy → elderly

� Gender大部分均是女性較多

Warthin’s tumor →男性較多

Diagnosis approach

� CT

� MRI

� Ultrasound

� Fine needle aspiration

� Core biopsy

Plemorphic adenoma

� Most common benign tumor of salivary gland

� Location : tail or superficial lobe

� CT : isodense to muscle and shows

moderate enhancement

� MRI : the mass is T1 hypointense (T2

hyperintense) to surrounding fat

Warthin’s tumor

� The second most common benign tumor of parotid

� Bilateral in 10% of cases and favors the tail of the parotid gland

� MRI : T1 hypointense to the surrounding

parotid fat

Mucoepidermoid carcinoma

� Most common malignant tumor of the parotid gland.

� CT : the mass is isodense to muscle

� MRI : T1 hypointense to surrounding

parotid fat but variable on T2

Adenoid cystic carcinoma

� The second most common malignant tumor of parotid

� CT : isodense to muscle

� MRI : T1 hypointense to surrounding

parotid fat but variable on T2

Final diagnosis

� Surgery :

1. excision of parotid gland tumor

2. superficial parotidectomy

� Pathology :

Epithelial-myoepithelial carcinoma

Discussion

Parotid gland tumor

� The most common location of salivary gland tumors

� Tumor usually present with a solitary, discrete, slowly growing, asymptomatic mass.

The rule of 80

� 80% of parotid tumors are benign

� 80% of parotid tumors are pleomorphicadenomas

� 80% of parotid pleomorphic adenomas occur in the superficial lobe

� 80% of untreated pleomorphic adenomas remain benign

Diagnostic evaluation

Fine needle aspiration

� Identify the causes of parotid enlargement

� Determine whether it is primary to the salivary gland or metastatic from another site

� The accuracy of FNA depends upon operator experience

Core needle biopsy

� Ultrasound-guided core needle biopsy of parotid masses is highly accurate (97~100%)

� More accurate typing and grading of malignant lesions

Image study

� Ultrasond

Location, the nature of the mass

� CT & MRI :

Provide important diagnostic information about overall dimension, adjacent tissue infiltration, and vascular invasion

It might be malignancy…

� Tumors of the deep parotid lobe or those which

extend into the parapharyngeal space

� Recurrent tumors

� Direct facial nerve invasion, skin involvement, or

extension into bone

� Locally extensive lesions

� The presence of pathologic cervical

lymphadenopathy

Staging system

Tumor invades skull base, and/or pterygoid plates and/or encases carotid artery

T4b

Tumor invades skin, mandible, ear canal, and/or facial nerve.T4

a

Tumor more than 4 cm and/or extraparenchymal extensionT3

Tumor more than 2 cm but not more than 4 cm in greatest dimension without extraparenchymal extension

T2

Tumor 2 cm or less in greatest dimension without extraparenchymal extension

T1

No evidence of primary tumorT0

Primary tumor cannot be assessedTX

Tumor size

Staging system

Metastasis in a lymph node more than 6 cm in greatest dimensionN3

Metastasis in bilateral or contralateral lymph nodes, none more than 6 cm in greatest dimension

N2c

Metastasis in multiple ipsilateral lymph nodes, none more than 6 cm in greatest dimension

N2b

Metastasis in a single ipsilateral lymph node more than 3 cm but not more than 6 cm in greatest dimension

N2a

Metastasis in a single ipsilateral lymph node, more than 3 cm but not more than 6 cm in greatest dimension, or in multiple ipsilateral lymph nodes, none more than 6 cm in greatest dimension, or in bilateral or contralateral lymph nodes, none more than 6 cm in greatest dimension

N2

Metastasis in a single ipsilateral lymph node, 3 cm or less in greatest dimensionN1

No regional lymph node metastasisN0

Regional lymph nodes cannot be assessedNX

Nodal status

Staging system

M1Any NAny TStage IVC

M0N2-3Any T

M0Any NT4bStage IVB

M0N2T1-4a

M0N0-1T4aStage IVA

M0N1T1-3

M0N0T3Stage III

M0N0T2Stage II

M0N0T1Stage I

Tumor stage grouping

Treatment---T1/T2

� Superficial or total parotidectomy with conservation of the facial nerve

� low-grade T1 and T2 primaries can be adequately treated by surgery alone

� RT is recommended for …..

� Deep lobe parotid tumors

� Close or positive histologic surgical margins

� Undifferentiated or high-grade histology

� Recurrent malignancy

� Bone or connective tissue involvement

� Metastatic regional cervical lymph nodes

� Perineural involvement

� Intraoperative tumor spillage or capsular rupture

Treatment---T3/T4

� Superficial or total parotidectomy +

postoperative radiotherapy

� Five-year survival rates for patients treated with and without RT were :

51% : 10%

Prognosis

� 10-year survival rates ：

14%Stage Ⅳ

43%Stage Ⅲ

69%Stage Ⅱ

85%Stage Ⅰ

Epithelial-myoepithelial carcinoma

( EMEC )

� A rare tumor accounting for slightly fewer than 1% of salivary gland neoplasms.

� Most often in elderly patients

� More prevalent in women

� The slow-growing mass is well defined, bulky lobulated fashion

CT & MRI

� CT : isodense to muscle

� MRI : hypointense on T1

� CT and MRI appearances of EMEC are nonspecific, and that EMEC cannot be differentiated from more common parotid neoplasms on the basis of its imaging characteristics.

Pathology

� The tumor has a distinctive histopathologicpattern with epithelial tubules or ductulessurrounded by neoplastic myoepithelialcells

Treatment

� Wide surgical resection, including adjacent lymph nodes

� Immediate postoperative radiotherapy

� Regular follow up

Prognosis

� There is a high reported rate of local recurrence, approaching 50%

� Resection of recurrences usually results in a good prognosis, with less than 10% of patients dying as a result of this tumor

Reference

� Uptodate : salivary gland tumor

� Robbins

�電腦斷層攝影入門

� Journal of clinical pathology :

Epithelial-myoepithelial carcinoma of salivary glands

� American Society of Neuroradiology

Epithelial-Myoepithelial Carcinoma of the Parotid Gland