1 Collective review Current management of parotid gland neoplasm เรียบเรียงโดย นพ.ประเสริฐ ปริธัญ อาจารยที่ปรึกษา อ.นพ.รุงโรจน กั่วพานิช Content • Histological reviews • Basic knowledge o Embryology o Histological o Anatomy • Natural history o Incidence o Etiology o Benign tumor o Malignant tumor • Clinical evaluation o Symptoms and signs o Investigations • Management • Complications
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Collective review Current management of parotid gland neoplasm
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Collective review Current management of parotid gland neoplasm
Metastatic neoplasms From Wenig B: Major and minor salivary glands. In Wenig BM (ed): Atlas of Head and Neck Pathology. Philadelphia, WB Saunders, 1993, p. 273.
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Figure 8. 60-year-old man with pleomorphic adenoma of the parotid gland.
Figure 9 Pleomorphic adenoma of the deep lobe of a parotid gland, causing medial displacement of the palate and tonsil.
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Figure 10 Gross section of pleomorphic adenoma. Irregular, round to ovoid mass Well defined borders In major salivary gland: Incomplete fibrous capsule or unecapsulated. In minor salivary
gland: Unencapsulated Homogeneous tan to white cut surface Hemorrhage and infarction on occasion
1. High grade tumor a. High grade mucoepidemoid carcinoma b. Adenoid cystic carcinoma c. Adenocarcinoma d. Squamous cell carcinoma e. Undifferentiated carcinoma
2. low grade tumor a. low grade mucoepidermoid carcinoma b. acinic cell carcinoma c. low grade adenocarcinoma
factor (locoregional control และ survival) โดยในปจจบนไดใชระบบ TNM classification เปนการแบงstaging ของตวโรค
TNM Staging System
แพทยผใหการรกษาจาเปนตองตอบคาถามทสาคญ 3 ขอ อนไดแก
• How large is the primary tumor? (T, Tumor) • Has the tumor spread to the lymph nodes? (N, Node) • Has the cancer metastasized (spread) to other parts of the body? (M, Metastasis)
Tumor. Using the TNM system, the "T" plus a letter or number (0 to 4) is used to describe the size and location of the tumor. When describing "T" in cancers of the major salivary glands doctors use these terms. TX: Means the primary tumor cannot be evaluated. T0: Is used when no evidence of a tumor is found. T1: Is a small non-invasive tumor of no more than 2 cm (less than an inch). T2: Is used to describe a larger noninvasive tumor, between 2 cm to 4 cm. T3: Tumor that is larger than 4 cm but not larger than 6 cm that has spread beyond the salivary glands but does not affect the seventh nerve, the facial nerve that controls expression such as smiles or frowns. T4a: The tumor invades the skin, the jawbone, the ear canal, and/or facial nerve. T4b: The tumor invades the skull base and/or the nearby bones and/or encases the arteries. Regional Lymph Nodes (N). The "N" in the TNM system is an abbreviation for regional lymph node. The lymph nodes are tiny bean-shaped organs that are located throughout the body that help the body fight infections and cancer. They are an important part of the body's immune system. There are many nodes located in the head and neck area and careful assessment of lymph nodes is an important part of staging cancer of the major salivary glands. NX: Means the regional lymph nodes cannot be evaluated. N0: Is used when there is no evidence of cancer in the regional nodes. N1: Indicates that cancer has spread to a single node on the same side as the primary tumor and the cancer found in the node is 3 cm (just over an inch) or less. N2: Describes any of these conditions: N2a: Cancer has spread to a single lymph node on the same side as the primary tumor, and is larger than 3 cm but not more than 6 cm. N2b: Cancer has spread to more than one lymph node on the same side as the primary tumor, and none measure more than 6 cm. N2c: Cancer has spread to more than one lymph node on either side of the body, and
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none measure more than 6 cm. N3: Cancer found in lymph nodes is larger than 6 cm. Distant Metastasis. The "M" in the TNM system describes cancer that has spread to other parts of the body. MX: Is used when distant metastasis cannot be evaluated. M0: Means the cancer has not spread to other parts of the body. M1: Doctors use this to describe cancer that has spread to other parts of the body. Stage grouping The information from the TNM system is grouped into a graduated set of staging, using the term stage 0 to IV (zero to four): Stage I: Describes non-invasive tumors (T1, T2) with no spread to lymph nodes (N0) and no distant metastasis (M0). Stage II: Is a tumor an invasive tumor (T3) that has not spread to lymph nodes (N0) or to distant parts of the body (M0). Stage III: Includes smaller tumors (T1, T2) that have spread to regional lymph nodes (N1) but have no sign of metastasis (M0). Stage IVA: Is used for any invasive tumor (T4a) with either no lymph node involvement (N0) or spread to only a single same-sided lymph node (N1), but no metastasis (M0). It is also used for T3 tumor with one-sided nodal involvement (N1) but no metastasis (M0) or any T with extensive nodal involvement (N2). Stage IVB: Is used for any cancer (T) with more extensive spread to lymph nodes (N2, N3) and no metastasis (M0). Stage IVC: Describes any cancer with distant metastasis (M1). Used with permission of the American Joint Committee on Cancer (AJCC), Chicago, Illinois. The original source for this material is the AJCC Cancer Staging Manual, Sixth Edition (2002) published by Springer-Verlag New York, www.springer-ny.com.
c. status of cervical lymph node มะเรง parotid จะเรมกระจายไปทตอมนาเหลองท intraglandular และ extrag;andular lymph node กอน แลวจงกระจายตอไปยง deep jugular chain ตาม level ท II, III, IV และ V (จากบนลงลาง) โดยท level ท I ,กระจายไปนอย
บทบาทของ FNA ในการวนจฉย parotid mass ยง controversy ทงท FNA เปนหตถการทคอนขางปลอดภย ทาไดงาย และประหยด เนองจากมคาถามเกดขนคอ FNA มความจาเปนทจะใชในการวนจฉย parotid mass หรอไม และทาแลวผลทไดจะเปลยนแนวทางในการรกษา หรอไม เพราะแนวทางในการรกษาของ parotid mass ยงคงอาศย clinical assessment เปนหลก
fig 16 A small piece of salivary gland is removed for examination by needle biopsy if abnormal lumps are found, or to test for Sjogren syndrome. The biopsy needle removes a small "core" of gland tissue which is sent to the laboratory for analysis.
f igure 17 Axial computed tomography with intravenous contrast showing a mass in the oral cavity, which exhibits an enhancing irregular border, with surface ulceration (arrow).The low density center is consistent with necrosis. These findings are highly suggestive of a malignant neoplasm. There is no evidence of gross invasion of the mandible. The biopsy confirmed malignant mixed tumor.
Figure 18 A 35-year-old patient presented with gradually progressive facial palsy. The ipsilateral parotid gland was slightly more prominent, but no distinct masses were palapable. A, An axial and B, a coronal magnetic resonance imaging scan showed a mass within the deep lobe of the parotid gland. This well-defined mass had smooth borders and enhanced brightly in A, the T1-weighted (with gadolinium); and B, the T2-weighted images. Surgical exploration revealed a facial nerve neuroma. The tumor was resected with reconstruction of the facial nerve with a cable graft. At 3-year follow-up evaluation, the patient has a House-Brackman grade III facial function and no evidence of recurrence. [from Cumming]
Figure 19 A, A 40-year-old man with a large, painless parotid mass, which has been slow-
growing. The fine-needle aspiration biopsy was indeterminate. B, An axial computed tomography with intravenous contrast demonstrating a large, rounded, well-defined mass, with smooth borders in the parotid gland. The mass was nonenhancing and had the same density as the subcutaneous fat. These findings were pathognomonic of parotid lipoma. A superficial parotidectomy was performed, and the diagnosis was confirmed.
TABLE 4 -- Neutron versus photon therapy for inoperable salivary gland cancers
2-year follow-up Neutron
therapy, % Photon
therapy, % P value
Initial complete response 85 33
Locoregional control 67 17 P < 0.005
2-year survival rate 62 25 P = 0.10
Griffin TW and others: Neutron vs photon irradiation of inoperable salivary gland tumors: results of an RTOG-MRC cooperative randomized study, Int J Rad Oncol Biol Phys 15:1085, 1988.
Indication for radiation therapy [3][6][20][32][33]
- tumor more than 4 cm in greatest diameter - high grade tumor - tumor invasion of local structure - lymphatic invasion - neural invasion - vascular invasion - tumor present very close to a nerve that was spreading - tumor originating in or extending to the deep lobe - recurrent tumor following re-resolution - positive margin on final pathology and LN involvement
Surgical therapy การรกษาโดยการตดเอากอนเนองอกออก ยงคงถอเปน mainstay สาหรบการรกษา primary salivary gland tumor ทกชนด หลกในการรกษาขนกบ site of origin of tumor Superficial parotidectomy with identification and dissection of the facial nerve เปน operation ทนอยทสดทใชสาหรบใหการวนจฉยและการรกษาของ parotid mass ทงนทงนนอาจเลอกทา incisional biopsy หรอ enucleation รวมดวยกได [1][3][5][6][11][12][13][16]
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Operative management of parotid gland malignancy ในปจจบนการรกษา parotid gland malignancy คอ aggressive surgical resection และตามดวย radiation therapy เมอมขอบงช conservative excision จะมอตราการกลบเปนซาทคอนขางสง ขอบเขตในการ resection ขนกบ tumor histology, tumor site and location, invasion of local structures และ status if regional nodal basins Tumor สวนใหญของ parotid gland นน ประมาณ 90% มตนกาเนดใน superficial lobe ดงนน superficial parotidectomy เปน operation ทนอยทสดทใชในการรกษา parotid gland neoplasm Operation นเหมาะสมในการรกษา tumor ทอยเฉพาะ superficial lobe เปน low grade histology, greatest diameter less than 4 cm, no local invasion and no evidence of regional involvement ขนตอนทสาคญในการผาตดคอ idenification facial nerve and branches ทแทรกตวอยใน parotid gland โดยใช nerve stimulator และหลกเลยงการใช paralytic anesthetic agents ชวยในการคนหา facial nerve จากการศกษาของ Aimoni และคณะ ทาการศกษาเกยวกบการประเมน facial nerve function ทง preoperative and postoperative โดย electroneurograhic monitoring ซงเครองมอท sensitive มากในการ monitor facial nerve function ทงกอนและหลงผาตด วามความผดปกตของการทางาน ทงจาก tumor เองและจากการผาตด
Surgical techniques
Superficial parotidectomy [6]
Perform surgery with the patient under general anesthesia without paralysis. The face and neck are exposed and covered with a transparent adhesive drape for visualization of facial motion throughout the case. A properly designed incision allows adequate exposure and will yield a good cosmetic result. An incision is made in the preauricular crease. It may be taken posterior to the tragus. It is extended to the attachment of the lobule and carried over the mastoid tip. The incision is then extended into the neck in a skin crease. Alternatively, a facelift incision may be used for hidden scar placement in the hairline. As shown in fig.19
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Figure 20 Exposure of the facial nerve and its inferior division: cervical–parotid approach
A Shaw hemostatic scalpel may be used to maintain hemostasis of the incision. Alternatively, a vasoconstrictive agent may be infiltrated into the skin. Take care not to inject deeply if an anesthetic agent, such as lidocaine or bupivacaine, is used. Some surgeons do not recommend the use of a local anesthetic because of the risk of facial paralysis.
Elevate a skin flap from the underlying parotid fascia, which has silvery sheen. Carry the flap anteriorly to the posterior border of the masseter muscle. Take care anteriorly so as not to disrupt the peripheral branches of the facial nerve.
The next step is to identify the main trunk of the facial nerve. Successful and rapid identification is achieved by taking advantage of known anatomic landmarks and wide exposure. Dissect the tail of the parotid gland anteriorly off the sternocleidomastoid muscle. Take care to preserve the greater auricular nerve if possible. Dissect the tail medially until the posterior belly of the digastric muscle is identified. The posterior belly of the digastric muscle is an important landmark for identifying the facial nerve, as the nerve may be identified just superior the muscle at approximately the same depth.
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Figure 21 Separation of tail of parotid from sternocleidomastoid, usually requiring sectioning of greater auricular nerve
Next, perform dissection along the anterior aspect of the tragus along the perichondrium. Maintain a wide plane and retract the parotid gland medially. The cartilage will form a point medially, termed the tragal pointer. The facial nerve lies approximately 1 cm deep to this landmark, slightly anterior and inferior. A more reliable landmark is palpation of the tympanomastoid suture line in this region, which separates the mastoid tip from the tympanic portion of the temporal bone. The main trunk of the facial nerve lies at approximately this level or slightly medial. The styloid process may be palpated, and the facial nerve will lie between the styloid process and the posterior belly of the digastric muscle as it inserts on the mastoid tip.
Figure 22 Blunt dissection of parotid gland from external auditory canal cartilage exposes tragal pointer. The facial nerve lies approximately 1 cm deep and slightly anteroinferior to pointer, and 6 to 8 mm deep to tympanomastoid suture line.
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The bridge of tissue created between the preauricular dissection and the dissection to the digastric muscle is divided superficially, and then blunt separation of soft tissues is performed in the direction of the facial nerve to identify the main trunk. A nerve stimulator may be helpful in locating the main trunk and branches, but use it sparingly.
In tissue beds previously operated on or in situations in which bulk tumor causes obstruction, this classic method of identifying the facial nerve may be impractical. In these situations, a peripheral branch of the facial nerve may be identified and traced posteriorly to the main trunk. Alternatively, the mastoid tip may be removed with a drill and the facial nerve identified intratemporally as it exits the stylomastoid foramen.
Once the main trunk of the facial nerve is located, use a fine-tipped hemostat to create a tunnel along the nerve and divide the parotid tissue superficially. This method of dissection involves 4 steps using the dissecting hemostat: push, lift, spread, and cut. If the facial nerve is constantly maintained in view, this method eliminates inadvertent injury.
Figure 24 Demonstration of technique of following each branch of facial nerve. A, Tunnels are created in plane of nerve. B, Overlying parotid tissue is cut with No. 12 blade. C, Each successive tunnel is serially connected to previous tunnel.
Identify the pes anserinus (the point of main division of the facial nerve) and dissect each branch of the facial nerve out to the periphery. Depending on tumor location, the surgeon may start with either the inferior or the superior division. Once one division is dissected, a tunnel over the next division superiorly or inferiorly is created and connected to the previous dissection. This is repeated for each branch of the facial nerve, reflecting the parotid gland and tumor away from the facial nerve, then dissecting the final soft tissue attachments after each branch of the nerve has been identified.
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Low-level stimulation of the facial nerve at the conclusion of the operation is performed to confirm that all branches are intact.
Figure 23 Marginal mandibular branch of facial nerve, which can reliably be found by tracing of posterior facial vein superiorly. Marginal division almost always crosses superficial to vein. Also diagrammed is relationship of buccal branch to parotid duct.
This technique yields an intact superficial portion of the parotid gland that contains the tumor. Careful hemostasis is achieved by using a bipolar cautery. Do not use monopolar cautery in vicinity of the facial nerve. Insert a closed suction drain through a separate stab incision in the hairline and close the wound in layers. Antibiotic ointment and a gauze dressing may be applied.
Figure 25 Nearly completed process, with tumor within intact superficial parotidectomy specimen.
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Total parotidectomy
Strictly speaking, total parotidectomy is a misnomer. The procedure, by definition, involves removal of as much parotid tissue medial and lateral to the facial nerve as possible, along with the accompanying tumor. Exact approach varies depending on tumor location, but it usually involves a superficial parotidectomy to identify and preserve the facial nerve, followed by removal of parotid tissue and tumor deep to the facial nerve.
Attempt to preserve the facial nerve at all times. The nerve is never sacrificed for benign disease and sacrificed only if malignancy is found to be directly infiltrating the nerve. In these situations, remove the involved branch with the specimen and obtain frozen sections to ensure clearance of tumor.
Group 2 includes T1 and T2 tumors with high-grade features (eg, high-grade mucoepidermoid carcinoma, adenoid cystic carcinoma, squamous cell carcinoma, adenocarcinoma, carcinoma ex-pleomorphic adenoma).
Sacrifice of the facial nerve or one of its branches ควรไดรบการจดการอยางเหมาะสม แตในรายทจาเปนตองตด facial nerve ออก อนเนองจากม tumor invade facial nerve หรอ high grade tumor การซอมแซม facial nerve ควรทาภายใต operating microscope ทนท [23][30]
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การ reconstruction สามารถทาไดหลายวธ คอ
• The ipsilateral or contralateral greater auricular nerve may be used as an interposition graft, although sacrificing sensation to the area normally supplied by this nerve.
• Another option is to anastomose the facial nerve to the ipsilateral hypoglossal nerve. This anastomosis may be performed end to side to avoid interfering with normal hypoglossal nerve function.
• During the period of waiting for facial nerve recovery, it is important to maintain corneal protection if the innervation to the orbicularis oculi has been interrupted.
• Measures include taping the eye closed at night over ophthalmic ointment and frequent use of wetting drops during the day. Some authors recommend a moisture chamber.
การวนจฉยของ Frey syndrome ในกรณทอาการไมชดเจนนน พบวามการใช minor’s match iodine test ซงไดมการพดถงครงแรกโดย Victor Minor เปน neurologist ชาวรสเซย โดยใช iodine solution ทาบรเวณตาแหนงทสงสยแลวปลอยใหแหง จากนนโรยแปงไปยงตาแหนงของ iodine ทแหง ถาม clinical gustatory sweating จะพบเหงอทออกมาจะละลายแปง แลวทาปฏกรยากบ iodine เปลยนเปนส dark blue [29]
สาหรบการ prophylactic intraoperative ของการเกด Frey syndrome อาจมหลายวธ เชน ยกskin flap ใหหนาขน, fascia lata graft, superficial musculo aponeurotic system (SMAS) [29]
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