Grossing of mandibulectomy specimen - Dr Pranav, MGIMS

Grossing Protocol at MGIMS, Sevagram

1. Pranav N Shirbhate GROSSING OF MANDIBLE

2. Headings Anatomy Definition Types of mandibulectomy General description Grossing techniques Histological sectioning

3. Anatomy

4. Definition Mandibulectomy is the resection of a part of thickness of the mandible or of a segment of the mandible. Often performed along with resection of the primary tumor in the oral cavity especially the buccal mucosa and gingival lesions. Sometimes to facilitate surgical resection as in case of large tumors and those located more posteriorly in the oral cavity.

5. When mandibular resection needed? Actual direct invasion to the cortex is rare. This usually occurs via a socket, e.g. an extraction or periodontal region disease or from retro-molar trigone carcinoma. However if the tumor is fixed to the periosteum & cortex, this in itself is believed an indication to consider removing the underlying cortex, it is better to remove the adjacent bone, either the margin if possible or segmental resection.

6. Types of resection Composite or commando resection Anterior mandibulectomy Marginal mandibulectomy Segmental or rim mandibulectomy Hemimandibulectomy Total mandibulectomy

7. Co mposite or commando resection Wide excision of the main lesion in the buccal mucosa, tongue or tonsil lying in close proximity with mandible together with suitable mandibulectomy and radical neck dissection where the entire specimen is received in one block ie en block resection ( Not commonly practiced now due to morbidity and reconstructive challenge and reserved for very advanced cancer) INDICATIONS T3/T4 tumors of buccal mucosa. Carcinoma tongue (anterior located, more than 2cm in size).

8. Anterior mandibulectomy In this the anterior or middle part of the mandible is excised along with the resection of the primary tumor, gingivolabial sulcus and sometimes a portion of the lip anteriorly and a part of the mucosa of the floor of the mouth posteriorly . This is done in the more anterior located tumors that involve the anterior gingivolabial sulcus.

9. A primary tumor, gingivolabial sulcus and portion of the lip anteriorly and a part of the mucosa of the floor of the mouth posteriorly requiring ant mandibulectomy.

10. Marginal or rim mandibulectomy Removes a portion of the mandible (usually the alveolus and the medial plate) without disrupting continuity of the bone. This is typically performed when tumor involves the periosteum without bone invasion. INDICATIONS Carcinoma lip with mandibular invasion. Carcinoma mandibular alveolus. Carcinoma of the buccal mucosa invading the mandible. Carcinoma of the floor of the mouth.

11. A lateral resection for a lesion involving the alveolus Large submandibular node fixed to the lower edge of the mandible, requiring bone resection

12. Segmental mandibulectomy In this a portion of the mandible is resected along with the primary tumor disrupting the condyl to condyl continuity. This is performed when tumor invades bone ie tumor beyond periosteum. INDICATIONS Carcinoma involving mandible. Squamous cell carcinoma of the floor of the mouth, oral cavity, oropharynx . Carcinoma of the buccal mucosa invading the mandible.

13. Hemimandibulectomy Done for more laterally placed lesions where in one half of the mandible is removed along with the tumor.

14. Resection in posterior segment . The retromolar trigone is the triangular part of the gingival mucosa that covers the ascending ramus of the mandible.

15. As this region is particularly small, tumor in this have already extended beyond and spreads into adjacent structures, so some prefer to classify growths in this area according to their predominant site of involvement. A posterior segmental mandibulectomy (along with the gingiva ) with or without removing the ramus of mandible along with some of the part of the gingival sulcus , buccal mucosa, anterior tonsillar pillar is performed in this tumors.

16. Cont.. If the tumor extends superiorly along the mucosa covering the ramus then a partial upper alveolectomy accompanies this specimen and is known as ‘ Bite resection’. Sometimes a part of the tongue or soft palate is included.

17. A dequate margin Adequate surgical margins are key to the successful cure of larger oral cancer. Histologically tumor strands frequently extend along tissue planes a centimeter or so from the visible or palpable edge. A 2 to 3 cm gross margin is what most surgeons recommend.

18. Type of neck dissection Structures removed Comprehensive neck dissection 1) “Classic” radical neck dissection All lymph-bearing tissue (levels I-V), Spinal accessory nerve ([CN] XI), Sternocleidomastoid muscle, and Internal jugular vein 2) Modified radical neck dissection “Classical neck dissection with sparing of one or more of the above structures Type I CN XI spared Type II CN XI and internal jugular vein spared Type III (functional neck dissection) All three structures spared (CN XI, internal jugular vein, and sternocleidomastoid muscle) Ie tissue from level I-V removed. Selective neck dissection Removal of lymph-bearing tissue from: Lateral Levels II-IV Posterolateral Levels II-V Supraomohyoid Levels I-III

19. Left sided neck dissection showing lymphatic zones, with the exception of level Ia.

20. Aim of dissection Answer questions that will lead to an accurate pathological diagnosis and pathologic staging if the tumor is present. Features of interest structures invaded by tumor whether the margins are free whether preoperative diagnostic imaging has given a true picture of tumor size and extension.

21. Equipment Well maintained dissecting knife, scissors, saws, scalpels, forceps, probe, chisel, and others. For maxillofacial specimens, a water cooled diamond grinding blade is mandatory – It allow slicing without separating the soft tissues from either bone or cartilage, and thus enable a cut surface to be obtained that clearly shows how the tumor involves the relevant anatomical structures.

22. Initial evaluation Accurate patient identification. Clinical history - including symptoms, past treatment, radiological findings and clinical suspicion. Specific specimen identification, including exact anatomical site. Any specific or special requests - should be noted.

23. Fixation Fix the whole specimen in formalin overnight in a refrigerator at temperature of 4⁰C. Teeth, if present should be removed before processing. Immersing a whole specimen in decalcification solution only allows further processing after a prolonged time but leads to unacceptable loss in quality of gross and microscopical features.

24. Orientation of specimen The size and type or resection for a mandibular tumor can vary from a small segmental resection to radical procedures as total mandibulectomy . The margins are easily remembered using the geometric shapes visualized for each component or can be fixed permanently by using India ink .

25. Anterior margin: bone. Posterior margin : bone or in case when mandibular condyle and coronoid are resected, then the pterygoid musculature and adjacent soft tissue. The medial and lateral margins will generally consist of oral cavity mucosa; however extensive tumor may invade soft tissue(both floor of mouth and lateral) and even skin.

26. Resection of the entire body of the mandible involves resection of the following muscles from anterior to posterior. On the lateral border : mentalis, depressor labii inferioris , trangularis , depressor anguli oris , platysma, buccinators and masseter. On the medial : genioglossus, genohyoid , ant. belly of the digastrics, mylohoid , medial pterigoid and superior pharyngeal constrictors.

27. Grossing Mandibular specimens are sawed perpendicular to the long axis of the mandibular body.

28. In the case of intraosseous lesions, record whether the lesion has caused expansion and/or attenuation of adjacent cortical bone or whether the tumour perforates the cortical bone. In squamous cell carcinoma of the oral mucosa, one should assess the relation between the tumour and the underlying mandibular bone, which may be resorbed away over a broad front or show diffuse penetration into the bone marrow

29. Scheme indicating the various ways in which a gingival cancer may involve the underlying mandibular bone. Vertical resorption, (B) horizontal resorption, (C) diffuse growth along the periodontal ligament space and surrounding the roots of involved teeth, and (D) resorption involving the periosteum only, without bone destruction.

30. Bone tumors:  Serially section the specimen with a saw at 0.5 cm intervals, then submerge in formalin overnight.  Place the sections in decalcification solution until they can be cut with a sharp knife. Mucosa/soft tissue tumors:  Carefully dissect the soft tissue off the bone, maintaining its orientation and avoiding excessive shredding.  Cont.

31. PROCEDURE & DESCRIPTION First orient the specimen. Describe the type of resection. Confirm the side and type of mandibulectomy . Measure the length of the mandible along the alveolar border. Record the number of teeth and there appearance. Sometimes a skin flap is resected in tumors that have spread to the overlying skin. Measure this skin flap and describe whether involved or free of tumor.

32. Locate the tumor and describe as: Site of the tumor (alveolar border, gingivobuccal sulcus, buccal mucosa) Size of the tumor (three dimensional, two dimentional if ulcer or plaque) Colour of the tumor. Appearance of the tumor (ulcerative, proliferative, papillary, verrucous, plaque like) Edges of the tumor. Invasion into the bone (on gross). Cut surface appearance. Note the distance of the mucosal cut margins from the tumor. Paint the mucosal and soft tissue surgical margins with India ink. Either blot dry or fix further in formalin.

33. Cont.. The application of indelible(permanent) ink as an aid to recognizing specimen margins on histologic slides is vital for margin assessment. Multiple colour may be necessary to identify specific margins for ressection . The ink is fixed to the tissue by modrant like 95% ethyl alcohol, 10% glacial acetic acid. Ink must be completely dried before sectioning to prevent ink tracking, seepage creating false positive margines .

34. Cont. For mucosal and soft tissue tumors separate the soft tissue from the mandible with a scalpel. The direction of the dissection should be from the inferior to superior and from the posterior to anterior aspect. The depth of invasion into the submucosal tissue, adjacent soft tissue and skin should be noted. Comment on the non- neoplastic mucosa as the presence of leukoplakia or any other lesion.

35. Cont … The bone is then fixed in special vise for cutting the mandible and a 3mm section of the bone with underlying tumor is taken. Mention the appearance of the bone on gross section. Bone sections are submitted for decalcification. If the lesion is in the alveolus the underlying bone should be sectioned.

36. Cont. If the specimen includes a radical neck dissection then lymph should be searched while the specimen is fresh. Avoid crushing the nodes by rough palpation. Fixed overnight in formalin or Carnoy’s solution and search for nodes next day. Described as: Number of nodes in each group. Size of the largest node in each group. Appearance on gross examination and obvious involvement by the tumor. Cut section appearance.

37. Sections for histology Tumor with its deepest extent(3-5 sections). Non- neoplastic mucosa. Mucosal surgical cut margins- medial, lateral, anterior and posterior. (or can go clock wise manner) Soft tissue surgical margins. Bone surgical margins.

38. In anterior mandibulectomy especially take a section to demonstrate the depth of infiltration into the muscle. Cut margins : Mucosal : anterior, right anterolateral and posterolateral , left anterolateral and posterolateral . A glossectomy and b/l supraomohoid node dissection may accompany the removal of these tumors.

39. 6. Lymph nodes - all lymphnodes dissected should be submitted for histology. - small nodes upto 3mm in thickness are submitted in toto . - large nodes are bisected and if necessary further sectioned into 2-3 mm slices. Sections of the bone if grossly involved or suspicious. Representative sections from nerve and vein, if present , as in RND.

40. Conclusion Although every case does not require significant diagnostic answers, if a standard technique is not applied in all routine situations, a challenging case will become a failure. The employment of appropriate tools and technique makes mandible processing, though not always easy, a success.

41. References. Rosai Ackerman : Textbook of surgical pathology . Complex head and neck specimens and neck dissections. How to handle them. P J Slootweg Manual of grossing: Tata memorial hospital . B. D Chaurasia , Text book of Anatomy, 4 th edition

42. Thank you and Regards!