Fig. 23.1
Melanoma, back of thigh
Fig. 23.2
Superficial spreading type
Fig. 23.3
Nodular melanoma with ulcer fixed to the bone
23.7 Staging of Melanoma
The clinical staging of melanoma is extremely important so as to describe the presentation stage. It involves:
(a)
Melanoma confined to the primary site. Any satellite nodule within 2 cm from the primary is designated as part of the primary.
(b)
Melanoma with metastasis to regional lymph nodes.
(c)
Melanoma with systemic metastasis.
However, microscopic staging of melanoma is important particularly for melanomas apparently restricted to the primary site. The more is the depth of involvement, the higher is the chance of metastasis to regional nodes. The Breslow and the Clark staging are the two most commonly used types. Of these, Breslow is more reproducible as it involves absolute depth of invasion.
Breslow staging and its significance (vertical thickness of melanoma in millimeters)
Stage | Depth |
|---|---|
I | Less than or equal to 0.75 mm |
II | 0.76–1.50 mm |
III | 1.51–2.25 mm |
IV | 2.26–3.0 mm |
V | Greater than 3 mm |
Clark staging (anatomical level of invasion)
Level of invasion | Description |
|---|---|
Level I | Lesions involving only the epidermis (in situ melanoma); not an invasive lesion |
Level II | Invasion of the papillary dermis; does not reach the papillary-reticular dermal interface |
Level III | Invasion fills and expands the papillary dermis but does not penetrate the reticular dermis |
Level IV | Invasion into the reticular dermis but not into the subcutaneous tissue |
Level V | Invasion through the reticular dermis into the subcutaneous tissue |
TNM staging
T (tumor size) | Depth | Subtypes |
|---|---|---|
Tis | Melanoma in situ | |
T1 | <1.0 mm | (a) Without ulceration and mitosis <1/mm2 (b) Without ulceration or mitosis >/=1/mm2 |
T2 | 1.0–2.0 mm | (a) Without ulceration (b) With ulceration |
T3 | 2.1–4.0 mm | (a) Without ulceration (b) With ulceration |
T4 | >4 mm | (a) Without ulceration (b) With ulceration |
N (regional lymph nodes) | ||
N1 | One lymph | (a) Micrometastasis (b) Macrometastasis |
N2 | 2–3 nodes | (a) Micrometastasis (b) Macrometastasis (c) In-transit metastasis/satellite without metastatic nodes |
N3 | >/= 4 nodes | Matted LN/in-transit nodules with nodal metastasis |
M (distant metastasis) | ||
M1a | Distant skin/subcutaneous/LN | LDH normal |
M1b | Lung metastasis | LDH normal |
M1c | All other visceral metastasis Any distant metastasis | LDH normal LDH elevated |
23.8 Prognostic Factors
1.
Depth of invasion
2.
Lymph node metastasis
3.
Anatomic location: Extremity melanomas have better prognosis than head and neck lesions (82 % versus 68 %).
4.
Presence of ulceration: Carries poorer prognosis than nonulcerated form.
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