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CUTANEOUS MALIGNANCIES
1. BASAL CELL CARCINOMA (BCC)
Basal cell carcinoma is the commonest skin malignancy in local population. It is usually on the face, nearly always after the age of 50 years. The early lesion is a small smooth papule which over several months or years enlarges to a rounded lesion with pearly nodules in a rolled edge , over which small dilated blood vessels course. Sometimes a crateriform ulcer is found in the centre, covered by a brownish crust. However, clinical variants occur and these include nodulocystic BCC, morphoeic BCC, superficial multicentric BCC and pigmented BCC. Basal-cell carcinoma only very rarely metastasize but it can be very destructive locally, even penetrating bone such as the skull, in which case death may result from sepsis.
Predisposing factors includes excessive sunlight exposure, X ray irradiation and arsenic poisoning. It can arise from other lesion such as sebaceous naevus. Certain genodermatosus e.g. Xenoderma pigmentosa, Gorlin's syndrome are also risk factors.
The diagnosis should always be confirmed by biopsy which shows proliferation of atypical basal cells with peripheral cells arranged in a regular row called palisading.
Depending on the patient's age and health, site, type, and size etc. of the tumour, basal cell carcinoma can be treated by surgical excision, radiotherapy, curettage and electrodesication and cryotherapy. All have a 5-10% recurrence rate. Mohs surgery, guided by frozen sections, is tissue sparing but time consuming. Long term follow up is required especially there is concern about adequacy of removal and the uderlying carcinogenic factors may lead to further primary tumours in the future.
2. SQUAMOUS CELL CARCINOMA
This tumour is more invasive than BCC. It can of metastasize via lymphatic channels to distant organs. Most tumours occur in elderly male, commonly on face, ear lobes and lower lips but can be found elsewhere in body. At presentation, the duration is measured in weeks or months. The tumour usually commences as a nodule which grows fairly rapidly. Ulceration may occur and the edges of the fully formed lesion are everted. If left untreated, a fungating mass will develop and erode into the adjacent tissues.
Squamous cell carcinoma may arise from skin previously affected by sunlight, burn, arsenic, irradiation, or hydrocarbon. It can also develop from any chronic ulcer or scar, dysplastic epithelium of leukoplakia as well as Bowen's disease. Pipe smokers are prone to have tumour on the lip or tongue. It is commoner in certain genodermatosis,e.g., Xeroderma pigmentosa.
The choice of treatment usually lies between radical surgery and radiotherapy depending the patient as well as tumour factors. Curettage is dangerously inadequate. Patients should be checked regularly at follow up.
3. MALIGNANT MELANOMA (MM)
This is a highly malignant tumour arising from melanocytes with tendency of early dissemination. It can develop from previously normal epidermis, presumably from malignant transformation of one eipidermal melanocyte or from a pre-existing melanocytic naevus (mole) where the cells are on the dermal side of the epidermodermal junction. It usually presents as pigmented growth or ulcer, though rarely could show little or no pigmentation (amelanotic melanoma). Four main clinicopathological variants are noted, namely superficial spreading mm , nodular mm, acral lentiginous mm and lentigo maligna mm.
Any pigmented lesion which has grown or changed rapidly should be carefully examined for the following signs :
A : A symmetry
B : Irregular B order
C : Variegate C olour
D : D iameter > 6 mm
E : E levated lesion
Others : spontaneous ulceration or bleeding
satellite lesions
enlarged regional lymph nodes
Predisposing factors include excessive ultraviolet irradiation (episodic acute UV exposure), skin type 1 (white skin races), pre-existing melanocytic naevus (giant congenital melanocytic naevus, dysplastic naevus, very large number of moles > 100) and family history of melanomas.
Histologically, malignant melanoma consists of hyperplasia and proliferation of pleomorphic atypical melanocytes with tendency for dyshesive and irregular nesting. Prognosis is related to the depth of invasion, i.e., the thickness of the tumour and this could be expressed by Clark's level (level I to V depending on whether the tumour is intraepidermal, dermal or penetrating subcutaneous fat) or a Breslow thickness, which is the distance in millimetres from the stratum granulosum of the epidermis to the level of the deepest tumour cells seen.
Early detection and adequate surgical excision is important. Very wide excision may decrease local recurrence but has no significant improvement in survival. Routine regional lymph nodes removal is controversial. Adjuvant chemotherapy can be added for tumours with poor prognosis or where there is known metastasis. Radiotherapy has no value. All body surfaces should be carefully examined and first degree relatives screened for melanoma. Long term surveillance is mandatory because patient is at significant risk of developing a second primary tumour
4. CUTANEOUS T CELL LYMPHOMA
4.1 Mycosis Fungoides
This is a very slowly evolving infiltration of the skin by T-helper lymphocytes, only terminally becoming systemic. The mean age of onset is about 50 with male 2 times commoner than female. For simplicity, the disease could be classified into the following clinical stages.
Stage 1 : Eczematoid or psoriasiform lesions with pruritus
Stage 2 : Infiltrated plaques, often with bizarre shapes
Stage 3 : Nodules, tumours, ulceration
Stage 4 : Lymph node involvement with or without systemic involvement
Patient can present with a mixture of lesions of different stages. However, most patient remains in stage 1 and 2 for long period and die from other causes.
Skin biopsy shows dense upper dermal lymphohistiocytic infiltrate with eipidermal invasion by lymphocytes to form 'Pautrier microabscesses'. At early stages, multiple and repeated biopsies at interval of months may be necessary to confirm the diagnosis. Special techniques include electronmicroscopy and T cell receptor gene rearrangement are sometimes helpful. Apart from skin biopsy, peripheral blood smears, chest X ray, bone marrow biopsy, and biopsy of abnormal lymph glands are indicate. Ultrasound or CAT scan of liver and spleen are non-invasive and probably worthwhile.
Treatment should be individualised and according to the stage of disease. In stage 1, topical steroid application is usually sufficient. PUVA therapy is indicated when there is widespread infiltrated plaques. Topical nitrogen mustard is an alternative for stage 2 disease but is more difficult to handle than PUVA. Radiotherapy is useful for localised nodules or tumours and electron beam therapy may be employed for widespread stage 3 disease or patients who break through while on PUVA therapy. Combination chemotherapy is unhelpful and carries considerable morbidity. Other alternatives in treatment include oral retinoids, interferon, and photopheresis etc.
4.2 Sezary's Syndrome
This is a rather rare disease of the elderly male, arising de novo or resulting from extension of pre-existing mycosis fungoides. Essential diagnostic clinical features include erythroderma, generalised pruritus and Sezary cells (abnormal T lymphocytes) of more than 1,000/mm³ in peripheral blood. Generalised lymphadenopathy is common.
In skin biopsy, malignant T cells may be seen within the lumina of dermal blood vessels, as well as in the dermis and epidermis.
Treatmentwise, chemotherapy (steroid and chlorambucil), PUVA and leucopheresis could be tried but the prognosis is poor. Most patients die within on year, usually from opportunistic infection.
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