Fast Facts: Skin Cancer by unknow

Author:unknow
Language: eng
Format: epub
Publisher: Health Press Limited

The histopathological features of melanoma differ between subtypes. However, in general, the radial growth phase – the process by which a pigmented lesion extends horizontally – correlates with the proliferation of atypical melanocytes within the epidermis or papillary dermis. This is followed by the vertical growth phase, except in nodular melanoma, in which there is no radial growth phase.

In lentigo maligna, the atypical melanocytes are usually confined to the basal layer of the epidermis, where they occur singly or in nests, and may extend to the adnexal epithelium. This transforms to lentigo maligna melanoma when it develops an invasive component.

Superficial spreading melanoma is characterized by proliferating atypical melanocytes present at all levels of the epidermis.

Nodular melanoma is comprised of a dermal mass of melanoma cells and, although there may be some invasion to the overlying epidermis, the tumor does not have an intraepithelial component.

Physical examination. An individual recently diagnosed with melanoma requires a thorough physical examination to search for any lymphadenopathy, hepatomegaly or other suspect pigmented lesions. If any such abnormalities are identified on physical examination, further investigation is required. There is strong evidence that routine imaging and blood tests have little, if any, value for the asymptomatic patient who has a normal physical examination and a Breslow thickness of 4 mm or less.

Staging. The AJCC provides a melanoma staging system that is widely accepted around the world. The British melanoma guidelines suggest that no further investigations are required for asymptomatic patients with stage I, II or IIIA disease. However, for those with stage IIIB or IIIC melanoma, CT scanning of the head, chest, abdomen and pelvis is recommended. This would normally exclude metastases, which is important in the pretreatment workup for lymph node dissection or regional chemotherapy. Furthermore, the guidelines recommend measurement of lactate dehydrogenase level for all patients with suspected stage IV disease, with consideration of entire body imaging for this group (Table 3.6).

TABLE 3.6 Cancer staging for cutaneous melanoma StagePrimary tumor (T)Lymph nodes (N)Metastases (M)

IA ≤ 1 mm, no ulceration, mitoses < 1/mm2 – –

IB ≤ 1 mm, with ulceration or mitoses ≥ 1/mm2* 1.01–2 mm, no ulceration – –

IIA 1·01–2 mm, with ulceration 2·01–4 mm, no ulceration – –

IIB 2·01–4 mm, with ulceration > 4 mm, no ulceration – –

IIC > 4 mm, with ulceration – –

IIIA Any Breslow thickness, no ulceration Micrometastases 1–3 nodes –

IIIB Any Breslow thickness, with ulceration Any Breslow thickness, no ulceration Any Breslow thickness, no ulceration Micrometastases 1–3 nodes 1–3 palpable metastatic nodes No nodes, but in-transit or satellite metastasis/es –

IIIC Any Breslow thickness, with ulceration Any Breslow thickness, with or without ulceration Any Breslow thickness, with ulceration Up to 3 palpable lymph nodes ≥ 4 nodes or matted nodes or in-transit disease + lymph nodes No nodes, but in-transit or satellite metastasis/es –

IV, M1a – – Skin, subcutaneous or distant nodal disease

IV, M1b – – Lung metastases

IV, M1c – – All other sites or any other sites of metastases with raised LDH

*In the rare circumstances where mitotic count cannot be

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