Melanoma Flashcards
How do junctional naevi present
common moles in prepubertal children, appearing as flat,
hairless, well-defined brown patches. On close inspection the normal skin markings are present and this
distinguishes them from melanomas
How is a junctional naevus characterized histologically
Focal proliferation of melanocytes which remain in contact with the epidermis (Junctional activity)
What is the natural history of a junctional naevus
Junctional –> Compound –> intradermal
Very few become malignant
How do compound naevi present
These are commonly found in adolescents as dark brown or black, elevated or nodular lesions. They may
be hair-bearing
What is seen histologically in a compound naevus
junctional activity as well as nests of naevus
cells in the dermis. The cells become smaller as they progress more deeply into the dermis. This is known as `maturation’
Presentation of an intradermal naevus
Grossly, the appearance is variable. It can be flat, raised, nodular or pedunculated. It may be pigmented or
non-pigmented and hairs may be present
Presentation of a spindle cell (Spitz) naevus
Grossly, it appears as a raised lesion, often occurring on the face with a characteristic reddishbrown colour
How do dysplastic naevi differ from normal naevi
They are larger, more irregular in shape, indistinctly bordered and variably pigmented
Where do dysplastic naevi occur
They are commonest on the trunk but tend also to occur in unusual sites such as the scalp, buttocks and
breast.
Cumulative lifetime incidence of melanoma in a patient with dysplastic naevus
Lifetime incidence approaching 100 %
Major aetiological factor of malignant melanoma
sunlight
When should the development of malignancy within a naevus be suspected
- Change in size
- Change in outline
- Change in colour
- Change in elevation
- Change in the surface characteristics
- Change in the surrounding tissues
- intermittent itching or tingling
- Recurrent minor bleeding/ serous discharge
4 Clinicopathological types of melanoma
- Superficial spreading melanoma
- Lentigo maligna melanoma
- Nodular melanoma
- Acral lentiginous melanoma
What is the pre-metastatic phase of melanomas
the pre-metastatic phase is described as the radial growth phase and can be diagnosed clinically. During this period, the tumour grows radially without vertical penetration. Nodular melanoma, however, starts the vertical growth phase early
Which are the most important prognostic factor in malignant melanoma
depth of penetration and location
Where is superficial spreading melanoma seen
lesion is seen most often in early middle age on any part of the body, but especially on the lower legs of women
How does Lentigo maligna melanoma develop
It starts as a Hutchinson’s melanotic freckle which
appears as a brown or black macular lesion looking like a smudge of boot polish. It may enlarge and recede producing an irregular outline with paler areas due to regression. Initially it is impalpable, but with invasion,
palpable nodules develop
Which is the most common melanoma in the african population (seen as a separate clinical entity)
Acral lentiginous melanoma
Which lesions have greater incidence of metastatic spread
- Lesions reaching Clark level III, IV and V or lesions more than 1. 5mm thick
high risk areas (for recurrence) in malignant melanomas
upper back, posterolateral arm, posterior neck and posterior scalp
management of melanoma
- lesions should be excised for histology (elliptical excison biopsy; exceptionally large lesions - incision biopsy)
- Once diagnosis is confirmed; further excision of the skin surrounding the tumour may be indicated
- Lesions with penetration less than 0.76 mm need a margin of 1 cm
- lesions deeper than 2 mm – a margin of excision should be 3 cm
- Closure: skin grafting/ local skin flaps on the back
What parameters are used to microstage the melanoma
- Levels of invasion (Clarks levels)
- Depth of penetration (Breslow’s)
When is Hyperthermic regional limb perfusion done
- Prophylactic treatment of lesions in the lower limb deeper than 1.5 m, to prevent local or in transit recurrence
- Therapeutically for patients who present with local recurrence
What is the indication for prophylactic node dissection
During a mono-block resection when excision of the tumour and surrounding skin with lymph nodes is performed in continuity, occurring with a deeply penetrating primary tumour, which is situated over
or close to its draining lymph nodes
When is therapeutic lymphadenectomy done
When one or more lymph nodes is clinicall involved
What is the follow- up for patients with melanoma
Patients are examined clinically every two months
with routine chest x-rays and liver function tests at 6 monthly intervals for the first two years. In patients who are disease-free after two years, the period between follow-up visits is generally lengthened to a maximum of
6 months
Which is the most effective single agent chemotherapy for malignant melanoma
DTIC
What is the recommended radiotherapy for malignant melanoma
larger doses and the addition of hyperbaric oxygen may
provide satisfactory responses.
