Oral cavity & oropharynx
General
Staging-mucosal melanoma of the head & neck
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Staging-mucosal melanoma of the head and neck
Cite this page: Magliocca K. Staging-mucosal melanoma of the head & neck. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/oralcavitystagingmucosalmelanoma.html. Accessed December 23rd, 2024.
Definition / general
- Staging of mucosal melanoma of the head and neck refers to TNM staging of mucosal melanoma (MM) involving the nasal cavity, paranasal sinuses, oral cavity and less commonly, pharynx and larynx
- Mucosal melanoma staging is distinct from staging systems used for cutaneous melanoma and carcinomas of those sites listed above
Essential features
- ~67% of mucosal melanomas arise in the sinonasal tract, 25% are found in the oral cavity and the remainder occur only sporadically in other mucosal sites of the head and neck
- Even small cancers behave aggressively with high rates of recurrence and death
- To reflect this aggressive behavior, primary cancers limited to the mucosa are considered T3 lesions
- Anatomic extent criteria to define moderately advanced (T4a) and very advanced (T4b) disease are given below
- AJCC 7th edition staging was sunset on December 31, 2017; as of January 1, 2018, use of the 8th edition is mandatory
ICD coding
- ICD-10
- C44.301 - unspecified malignant neoplasm of skin of nose
- C06.0 - malignant neoplasm of cheek mucosa
- C05.9 - malignant neoplasm of palate, unspecified
Primary tumor (pT)
- pT3: tumors limited to the mucosa and immediately underlying soft tissue, regardless of thickness or greatest dimension; for example, polypoid nasal disease, pigmented or nonpigmented lesions of the oral cavity, pharynx or larynx
- pT4: moderately advanced or very advanced disease
- pT4a: moderately advanced disease; tumor involving deep soft tissue, cartilage, bone or overlying skin
- pT4b: very advanced disease; tumor involving brain, dura, skull base, lower cranial nerves (IX, X, XI, XII), masticator space, carotid artery, prevertebral space or mediastinal structures
Notes:
- Compared with disease confined to the nasal cavity, sinus involvement confers significantly worse survival; based on this, further stratifying the T3 stage was highly prognostic (p < 0.001) with implications for a potential modification to the current TNM staging system (J Neurol Surg B Skull Base 2022;84:307)
Regional lymph nodes (pN)
- pNX: regional lymph nodes cannot be assessed
- pN0: no regional lymph node metastases
- pN1: regional lymph node metastases present
Notes:
Prefixes
- c: clinical (cTNM)
- p: pathological (pTNM)
- y: postneoadjuvant chemoradiation therapy (ycTNM or ypTNM)
- r: recurrent tumor stage (rTNM)
Margin status assessment
- In mucosal sites, resections are often performed by obtaining multiple separate specimens, making margin assessment unreliable (Arch Pathol Lab Med 2019;143:603)
- In general, tumor margins are reported but margin status is not an independent prognostic factor for head and neck mucosal melanomas
- Some studies have shown the prognostic value of margin status, while others show no impact (Cancer 2010;116:2215, JAMA Otolaryngol Head Neck Surg 2017;143:1220)
- Very high propensity for vascular invasion may contribute to earlier distant metastasis, which contributes to overall mortality in this patient population, irrespective of margin status (Arch Pathol Lab Med 2019;143:603)
AJCC prognostic stage groups
| Stage III:
| T3
| N0
| M0
|
| Stage IVA:
| T4a
| N0
| M0
|
| Stage IVA:
| T3 or T4a
| N1
| M0
|
| Stage IVB:
| T4b
| any N
| M0
|
| Stage IVC:
| any T
| any N
| M1
|
Gross images
Images hosted on other servers:
Macroscopic appearance
Microscopic (histologic) description
Microscopic (histologic) images
Contributed by Kelly Magliocca, D.D.S., M.P.H.
Maxillectomy
Hard palate mucosa
Highly pleomorphic cells
HMB45 (red chromogen)
MelanA (red chromogen)
PRAME (red chromogen)
S100 (red chromogen)
SOX10 (red chromogen)
Board review style question #1
Which of the following findings corresponds to pT3 pathological stage for mucosal melanoma of the head and neck?
- 0.5 cm tumor invading and limited to submucosa
- 1.5 cm tumor invading skin
- 2.5 cm tumor invading bone
- 3.5 cm tumor invading carotid artery
Board review style answer #1
A. 0.5 cm tumor invading and limited to submucosa. pT3 mucosal melanoma tumors of the head and neck are limited to the mucosa and immediately underlying soft tissue, regardless of thickness or greatest dimension. Answers B, C and D are incorrect because tumor shows invasion into adjacent structures (skin, bone and carotid artery), necessitating pT4 staging.
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Reference:
Staging-mucosal melanoma of the head & neck Board review style question #2
The AJCC staging for mucosal melanoma (MM) is unique compared to cutaneous melanoma for which of the following reasons?
- Pathologic staging of mucosal melanoma begins at pT3
- Pathologic staging of mucosal melanoma requires molecular subtyping
- Pathologic staging of mucosal melanoma requires negative margin status
- Pathologic staging of mucosal melanoma restricts T3 staging to specific histologic subtypes
Board review style answer #2
A. Pathologic staging of mucosal melanoma begins at pT3. The majority of mucosal melanomas are invasive at presentation and for this reason, pathologic staging of mucosal melanoma begins at pT3. Answer B is incorrect because histological evaluation is used to stage mucosal melanoma. While some recurrent molecular alternations have been noted in mucosal melanoma, these results are not needed for staging (but may be relevant to therapy selection). Answer C is incorrect because negative margin status is not required for staging mucosal melanoma. Answer D is incorrect because histologic subtyping is not required for staging mucosal melanoma.
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Reference:
Staging-mucosal melanoma of the head & neck
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