MELANOMA (Cutaneous malignancy)
& NON-MELANOMA SKIN CANCERS (NMSCs)
This article is presented for general information only, it is not intended as an aid to self-diagnosis.
If you become aware of suspicious scalp head or neck lesions you should take medical advice without delay.
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Melanoma
A cancer arising from pigmented skin cells and body cavity linings. The incidence of this type of cancer is increasing worldwide. The International Agency for Research in Cancer has concluded that solar radiation, broad spectrum UVR, UVA (the most deeply penetrating wavelength), UVB and UVC radiations are all carcinogenic in laboratory animals.
In humans, excessive exposure to UVR increases the risk of serious adverse health effects especially cutaneous malignancies (skin cancer). The process may be thus described-
Excessive short-term exposure to UVR > ‘sunburn’ erythema (reddening through vasodilation) with oedema (swelling)
> ‘suntan’ due to increased melanin production > increased risk of eventual skin cancers (both non-melanoma and melanoma).
Melanomas can appear on the scalp.
Symptoms: a pigmented area which has recently appeared or changed in its colour, shape, size, or which begins bleeding or ulcerates e.g. a mole or nevus with varied colour, irregular borders, increasing in size or ulcerating.
Whereas the majority of scalp lesions have an almost nil risk of becoming melanomas, persons with suspicious lesions should visit their doctor without delay.
Diagnosis: by excisional biopsy which involves the complete removal of the pigmented lesion + a margin of surrounding normal tissue for gross and microscopic laboratory investigation.
Prognosis: Treatment methods are improving.
Treatment of melanoma is dictated by the stage of disease.
Thin lesions are more easily treated by surgical excision. The prognosis is usually excellent.
Thicker lesions evoke greater concerns. There is a possibility that other organs viz: regional lymph nodes in the neck, or the lungs, liver, or brain could be at risk. In such cases, physical examination, laboratory investigations and imaging may be required. Where there is no sign of metastasis (spread of disease to distant locations) treatment consists of excision of the primary tumor and possibly the removal of the lymph nodes in the neck for staging purposes.
Where metastasis is evident, treatment may involve a host of medical specialists and procedures beyond the scope of this article.
Non-Melanoma Skin Cancers (NMSCs)
(mainly Basal Cell Carcinomas and Squamous Cell Carcinomas).
NMSCs are relatively common in white skinned peoples., especially vulnerable are those with fair complexions and blonde or red hair. NMSCs are rarely fatal.
NMSCs can appear on the scalp
Symptoms: a pigmented area which has recently appeared or changed in its colour, shape, size, or which begins bleeding or ulcerates.
Whereas the majority of scalp lesions are harmless, persons with suspicious lesions should visit their doctor without delay.
Diagnosis: usually by excisional biopsy which involves the complete removal of the pigmented lesion + a margin of surrounding normal tissue for gross and microscopic laboratory investigation.
Malignancy with special reference to scalp
Dr A Ahir MD LTTS (Consultant Dermatologist)
Following are the few malignant lesions seen in scalp
1- Sebaceous carcinoma
History and nomenclature
Lever distinguished between the sebaceous carcinoma derived from the cells of the sebaceous gland and the basal cell or squamous epthelioma with sebaceous differentiation. Relatively few cases of sebaceous carcinoma of the skin have been reported; these tumours arise rather more frequently in the meidbomian glands but extra-ocular ones are well described. The peri-ocular variety is often aggressive and may metastasize widely. The confusion of these sebaceous carcinomas with basal cell epithelioma with sebaceous differentiation accounts for the conflicting opinions as to its degree of malignancy.
Pathology– The tumour consists of lobules of sebaceous cells in various stages of differentiation. Atypical cells and mitoses are frequent. The eosinophilic cytoplasm is foamy or finely granular. Lipid may be demonstrable, particularly in the better differentiated cells. The stroma which may be dense and fibrous contains lymphocytes and plasma cells. Histological distinction from basal cell epithelioma or squamous cell epithelioma with sebaceous differentiation must be mad .
Clinical features: The tumour occurs most often on the face or scalp mainly over the age of 50. the clinical appearance is not diagnostic; there is solid or ulcerated nodule which enlarges slowly. It may be yellow in colour but is not invariably so. Local invasion and metastasis may occur. The diagnosis must be confirmed histologically. Clinically, Markel cell carcinoma may present similarly but is much more aggressive.
2- Primary adenoid cystic carcinoma
A malignant carcinoma which may occur in salivary gland, lacrimal and ceruminous glands and many other sites , Meyrick Thomas described a case in the scalp a smooth swelling with overlying alopecia.
3- Basal cell carcinoma (basal cell epithelioma, rodent ulcer)
Aetiology- Basal cell carcinoma is not a rare tumour in the scalp. Tumours on the bald scalp do not differ from those in other light-exposed areas. Those in the hairy scalp may develop in scars. But many arise in previously normal skin for no known reasons. The development of one or more basal cell carcinomas in the scalp in middle age should lead to careful enquiry concerning ringworm in childhood.
Pathology- The pathology of these lesions in the scalp shows no features which distinguish it from that of basal cell carcinomas in other sites.
Clinical features- The typical smooth, translucent nodule, very slowly enlarging, with a few telangiectatic vassels crossing its surface occurs in the scalp as elsewhere. The nodule may be slightly or even deeply pigmented. Ulceration is frequent. The duration of the lesion when the patient seeks advice is measured in months or years. The multicentric basal cell carcinoma is particularly characteristic of the scalp. It presents a rolled mother of pearl margins, its surface is moist and crusted and atrophic or ulcerated. Throughout the lesion some hair follicles are present in patches. Such lesion can be alarmingly destructive, involving even the meninges if they are neglected.
Diagnosis- A biopsy should be taken as soon as the diagnosis is suspected. If the lesion is large biopsies should be taken from two or more sites. To give some indication of the depth of invasion of dermis or periosteum.
Treatment- very small carcinomas may be effectively treated by curettage, provided the patient can be kept under supervision, but wide excision is advisable. Wether excision or radio-therapy is preferred it is of the greatest importance to ensure that the initial treatment is adequate, for the treatment of recurrences presents even greater difficulties than in other parts of the body, modern surgical methods certainly give the best cosmetic results, particularly with large lesions, some authors suggest that MOHS micrographic surgery should be used for all but the smallest lesions.
4- Bowen’s disease.
This intra-epidermal carcinoma may occur in any part of the skin. In the scalp it occurs most frequently in areas long exposed to solar damage by balding but multicentric Bown’s disease has occurred in the hair multicentric Bowen’s disease has occurred in the hairy scalp. The lesion is a crusted, sharply marginated plaque which has been mistaken for psoriasis. It enlarges very slowly. An invasive squamous carcinoma may eventually develop. The diagnosis should be confirmed histologically. Lesions on hair sites should be excised. Those on exposed, bald areas respond well to liquid nitrogen cryosurgery.
5-Squamous cell carcinoma
Squamous cell carcinoma in the scalp is uncommon, but early diagnosis is of such importance in prognosis that a knowledge of its precursor is essential. The most frequent precursor of squamous carcinoma of the scalp is a solar keratosis. Such lesions occur in scalp which has long been bald and the lack of hair ensures that changes in the appearance of the keratosis should be rapidly detected. The scalp is not infrequently the site of bourns or scalp is not infrequently the site of burns or scalds in childhood. Squamous carcinoma may develop after an interval of many years in the log forgotten scar tissue. Skin damaged by X-ray epilation in the treatment of ringworm may later be the site of squamous carcinoma.
Clinical features: The development of induration around the base of a solar keratosis should be raise the suspicion of malignant change. Ulceration of a long standing scar does not necessarily simply a diagnosis of squamous carcinoma but I too is a indication for urgent biopsy. Any change in size or any ulceration of a chronic skin lesion of the scalp should be submitted to biopsy with the minimum of delay.
Treatment: If histological examination establishes the diagnosis of squamous carcinoma the management of the patient should be surgical though with dermatological surgery technique is applied will depend on the pathological type. The site and the size.
6- Malignant melanoma:
Aetiology , In most countries the incidenceof malignant melanoma is increasing, as is the mortality from it, this increase may be duein part to increased exposure to sunlight of those who are susceptible by virtue of their fair skins. The capacity to from protective pigment is of course itself genetically determind, but there is also a more specific hereditary tendency to develop melanoma; in such families the age of onset of the melanoma is early, multiple primary tumours are not unusual and the survival rate is higher than in patients with not familial melanoma.
Pathology: The neoplastic melanocytes may invade the dermis laterally or vertically and the extent and direction of this invasion determines the indications for treatment and the prognosis.
Clinical features: Any change in a congenital neavus should be regarded with suspicion, in particular localized increases in pigmentation , bleeding from an area of erosion, or complaints of itching or discomfort in the lesion. The nodular from of melanoma, usually in middle aged or elderly men, presents as a rather vascular reddish- brown nodule, raised or even pedunculated. The melanomas in congenital naevi and the nodular melonama may develop in hairy scalp and this delays their diagnosis, which in part accounts for their poor prognosis. In contrast the lentigo maligna melanoma usually develops in bald scalp as a flat brown patch; as this slowly extends the pigmentation becomes more in tensely black in some areas and redder in others. Even tually a nodule may from at a point within the pigmented are and may first present as localized crusting and ulceration. Melanoma rarely presents as an area of poliosis
Diagnosis: This involves a high level of suspicion of any pigmented lesion in the scalp or of any reddish-brown vascular nodule. If melanoma is considered to be a possible diagnosis excisional biopsy is desirable. If, however, the lesion is very large and excision would be a mutilating procedure incisional biopsy may be justifiable.
Treatment: This should be entrusted to an experienced plastic surgeon. The result of the surgical procedure will be determined by careful assessment of the clinical and histological features.
7- Dermatofiberoscaroma protuberans:
This rare tumour usually begins in early adult life, but the diagnosis is often made only after a considerable delay. It occurs most frequently on the trunk but is on the head or neck in over 10% of cases and has been reported in the scalp. Histrologically the tumour consists of spindle- shaped cells in a closely woven patter. Clinically there are protuberant from nodules arising on a diffusely thickened dermal plaque. Excision must be wide as the risk of recurrence is considerable.
8- Malignant angioendothelioma :
Aetiology: Malignant angioendothelioma of the face and scalp has been characterized as a distinct clinicopathological entity. Very rarely it may occur as early as the fourth decade but the average age of onset is between 70 and 80 years with men more frequently affected than women.
Pathology: The tumour consists of anastomosing irregular vascular channels and spaces which infiltrate but do not destroy the dermis. The channels are lined by atypical swollen endothelial cells which show a tendency to intra-luminal budding to form cords and islands of cells in syncytial arrangement.
Clinical features: The commonest presentation is with single or groped bluish-red nodules of the face and scalp. There may be some thinning of the hair over the tumours but alopecia is not a consipicuous feature of this form of the disease. Less well differentiated tumours appear as diffuse indurated plaques over which much hair is lost. Exceptionally there may be an extensive cicatricial alopecia. One morphological type is known to clinicians as the malignant bruise. Eventually a large area of face, neck and scalp may be involved, with grossoedema of the eyelids. The skin may ulcerate. Involvment of the cranial bones may occurand distant metastases are frequent. The average duration of survival after onset is under 2 years.
Treatment: palliative radiotherapy is the best that can be offer, though some authorities still recommend combined surgical and X-ray treatment has shown early optimism in two cases.
9- Carcinoma metastatic to the scalp.
Carcinoma of an internal organ may involve the skin directly from an underlying organ or by extension through lymphatics, by lymphatic or bloodstream embolic dissemination, or by accidental implantation of tumour cells during the course of surgical procedure. Te total incidence of cutaneous metastasis in patients with internal carcinoma has ranged from 2 to over 4%. The scalp is the site of such metastasis, particularly in hypernephroma and carcinoma of the breast but scalp metastasis also occurs from ovary and prostate, and more uncommonly, pancreas, live, uterus, salivary gland and bone. Meningiomas may reach the scalp by direct extension, through operative defects in the skull or by metastasis. Osteogenic sarcoma may appear to be primarily in the scalp.
Pathology: The cells in metastatic malignant deposits may retain recognizable characteristics of the primary tumour but may be too anaplastic for identification. Their metastatic origin is betrayed by their lack of connection with cutaneous epithelial structures, but occasionally involvement of the epidermis by the cells if the metastasis may make diagnosis more difficult. Columns of cells may be seen within dilated lymphatics. Vascular dilatation is a variable feature. The presence of mucin suggests that the primary tumour is in the digestive tract. In metastasis from hypernephroma the acinose arrangement of the cells of the original tumour may not be obvious, but vascular proliferation is often conspicuous.
Clinical features: Single or multiple firm non-tender nodules enlarging quit rapidly are the most frequent manifestation of metastatic carcinoma in the scalp. Some times when the patient’s tissue reaction to the metastasis has been more effective there may be some oedema and inflammatory changes. In other changes dermal sclerosis around the deposit leads to destruction of hair follicles and the metastasis presents clinically as single or multiple areas of cicatricial alopecia. Multiple nodules may simulate turban tumours but the latter develop slowly over many years.
Treatment: A biopsy should always be taken, and every attempt should be made to detect and treat the primary tumour. Usually the prognosis is very poor but, particularly in hypernephorma in which a solitary metastasis to the scalp may be the first evidence of the presence of the tumour, excision of both the affected kidney and the secondary may give a permanent cure. Excision of the metastasis is always advisable unless of course it proves to be only one manifestation of generalized carcinomatosis. Even the long-delayed metastasis developing years after mastectomy should be excised and the practicability of chemeotherapy should be discussed. The patient’s response to skin tests of delayed hypersensitivity may be of assistance in planning treatment.
References:
Diseases of the Hair and Scalp (by Rodney Dawber, Third Edition)
