Harrison's Internal Medicine Chapter 83. Cancer of the Skin
Melanoma Pigmented lesions are among the most common findings on skin examination. The challenge is to distinguish cutaneous melanomas, which may be lethal, from the remainder, which with rare exceptions are benign. Examples of malignant and benign pigmented lesions are shown in Fig. 83-1.
Atypical and malignant pigmented lesions. The most common melanoma is superficial spreading melanoma (not pictured). A.
There are four types of cutaneous melanoma (Table 83-2). In three of these—superficial spreading melanoma, lentigo maligna melanoma, and acral lentiginous melanoma—the lesion has a period of superficial (so-called radial) growth during which it increases in size but does not penetrate deeply. It is during this period that the melanoma is most capable of being cured by surgical excision. The fourth type—nodular melanoma—does not have a recognizable radial growth phase and usually presents as a deeply invasive lesion, capable of early metastasis.
(BQ) Part 1 book "Histopathology of the skin" presents the following contents: Histology of normal skin, techniques of skin biopsy, dermoepidermal junction, the cells of the skin and their identification, common terminologies used in dermatopathology, staining techniques in dermatopathology,... Invite you to consult.
(BQ) Part 1 book "Histopathology of the skin" presents the following contents: Pigmented purpuric dermatosis, dermatitis herpetiformis, sarcoidosis, lupus erythematosus, pyoderma gangrenosum, urticaria pigmentosa, gyrate and annular erythemas, seborrheic keratosis, basal cell carcinoma,... Invite you to consult.
(BQ) Part 1 book "Atlas and synopsis of lever's histopathology of the skin" presents the following contents: Disorders mostly limited to the epidermis and stratum corneum, localized superficial epidermal or melanocytic proliferations, disorders of the superfidal cutaneous reactive unit, acantholytic, vesicular, and pustular disorders.
(BQ) Part 2 book "Atlas and synopsis of lever's histopathology of the skin" presents the following contents: Perivascular, diffuse and granulomatous infiltrates of the reticular dennis; erivascular, diffuse and granulomatous infiltrates of the reticular dennis; inflammatory and other benign disorders of skin appendages; disorders of the subcutis.
It has long been noted anecdotally that affect, psychological
state and neurologic state have influences on
inflammatory skin diseases. Disorders such as psoriasis,
atopic dermatitis, acne and rosacea, among many
others, are reported to become exacerbated by stress.
Furthermore, it is widely believed that stress alters
cutaneous immunity. However, mechanisms responsible
for these effects have remained incompletely
understood. Scientific evidence for an influence of
the nervous system on immune and inflammatory
processes in the skin has been developed only relatively
Other Nonmelanoma Cutaneous Malignancies
Neoplasms of cutaneous adnexa and sarcomas of fibrous, mesenchymal, fatty, and vascular tissues make up 1–2% of NMSC (Table 83-6). Some can portend a poor prognosis such as Merkel cell carcinoma, which is a neural crestderived, highly aggressive malignancy that exhibits a metastatic rate of 75% and a 5-year survival rate of 30–40%. Others, such as the human herpes virus 8-induced, HIV-related Kaposi's sarcoma, exhibit a more indolent course.
The most important prognostic factor is the stage at the time of presentation. Fortunately, most melanomas are diagnosed in clinical stages I and II. The revised American Joint Committee on Cancer (AJCC) staging system for melanoma is based on microscopic primary tumor depth (Breslow's thickness), presence of ulceration, evidence of nodal involvement, and presence of metastatic disease to internal sites (Table 83-3). Certain anatomic sites may affect the prognosis.
The entire cutaneous surface, including the scalp and mucous membranes, should be examined in each patient. Bright room illumination is important, and a 7x to 10x hand lens is helpful for evaluating variation in pigment pattern. A history of relevant risk factors should be elicited. Any suspicious lesions should be biopsied, evaluated by a specialist, or recorded by chart and/or photography for follow-up. Examination of the lymph nodes and palpation of the abdominal viscera are part of the staging examination for suspected melanoma.
A lifetime risk of melanoma development of 6% has been estimated. The risk is greatest before age 5 and next greatest between ages 5 and 10. Early detection of melanoma is difficult in these lesions because of the deep dermal or subcutaneous origin of primary melanoma and because of the large and varied surface of the nevus. Prophylactic excision early in life can be accomplished by staged removal with coverage by split-thickness skin grafts. Surgery cannot remove all at-risk nevus cells as some may penetrate into the muscles or central nervous system below the nevus. At present there are...
Treatment of Metastatic Disease
Melanoma can metastasize to any internal organ, the brain being a particularly common site. Metastatic melanoma is generally incurable, with survival in patients with visceral metastases generally
Any pigmented cutaneous lesion that has changed in size or shape or has other features suggestive of malignant melanoma is a candidate for biopsy. The recommended technique is an excisional biopsy, as that facilitates pathologic assessment of the lesion, permits accurate measurement of thickness if the lesion is melanoma, and constitutes treatment if the lesion is benign.
Squamous Cell Carcinoma
The natural history of SCC depends on both tumor and host characteristics. Tumors arising on actinically damaged skin have a lower metastatic potential than those on protected surfaces. The metastatic frequency of cutaneous SCC, reported at 0.3–5.2%, occurs most frequently in regional draining lymph nodes. Tumors occurring on the lower lip and ear have metastatic potentials approaching 13 and 11%, respectively. The metastatic potential of SCC arising in scars, chronic ulcerations, and genital or mucosal surfaces is higher.
The skin plays an important role in maintaining the integrity of the living organism
while allowing the interaction of the organism with its environment. To fulfill these
functions, mechanical stability is as important as flexibility. The mechanical properties
of skin are very diverse depending on the anatomical location, and they evolve
throughout life from the fetus to old age. Both genetic and acquired skin diseases
modify skin biomechanics, as do intrinsic and photoaging.
For two main reasons, dermatology is one of the later medical disciplines to use imaging techniques: skin lesions are readily visible to the naked eye or through a magnifying glass, allowing clinical diagnosis with no invasive examination; skin lesions can easily be biopsied or removed for histological study. This approach has therefore remained the basis of clinicopathological diagnosis of skin diseases for a long time. There has also been a third factor.
(BQ) Part 1 book "The cutaneous lymphoid proliferations - A comprehensive textbook of lymphocytic infiltrates of the skin" presents the following contents: Introduction to the classification of lymphoma; the therapy of cutaneous T cell lymphoma; molecular analysis in cutaneous lymphoid proliferation; benign lymphocytic infiltrates; reactive lymphomatoid tissue reactions mimicking cutaneous T and B cell lymphoma,...
(BQ) Part 1 book "The cutaneous lymphoid proliferations - A comprehensive textbook of lymphocytic infiltrates of the skin" presents the following contents: Cutaneous mantle cell lymphoma, mycosis fungoides and sézary syndrome, subcutaneous panniculitis like t cell lymphoma, nasal and related extranodal natural killer cell T cell lymphomas and blastic plasmacytoid dendritic cell neoplasm,...
Part 1 book "Atlas of the human body" presentation of content: Fundamentals of anatomy and physiology, the nervous system, the skin, the skeletal system, the sensory system, the muscular system. Invite you to consult