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Hidradenitis suppurativa may be confused with a tumor, but it is an infection of the apocrine sweat glands and subcutaneous tissue that occurs most frequently in the axilla or groin. Treatment involves controlling the infection with antibiotics and (if indicated) incision and drainage, followed by excision with either primary closure or a split -thickness skin graft.

C

Premalignant skin lesions are benign lesions with a high likelihood of progressing to invasive squamous cell carcinoma.

Actinic keratosis is a rough, scaly epidermal lesion that occurs in areas of the body subjected to chronic sun exposure.

It may appear in the third or fourth decade of life, and approximately 10%–20% of the lesions undergo malignant transformation.

If biopsy proves the lesion to be benign, it is treated by excision or cryotherapy. Topical chemotherapy with 5-fluorouracil has been useful in patients with many keratoses.

Bowen's disease is intraepidermal squamous cell carcinoma or carcinoma in situ of the skin. It appears as a well-defined, erythematous plaque covered by an adherent scaly yellow crust.

There are no lymphatics in the layer affected, and there is no potential for metastasis.

Bowen's disease occurs mainly in the fourth to sixth decade of life, and ingestion of arsenic and viruses have been implicated as etiologic agents. Treatment is similar to that for actinic keratosis.

Keratoacanthoma is a locally destructive skin lesion that is found most commonly on the head, neck, and upper extremities.

Rapid progression of the tumor occurs within 2–8 weeks, followed by spontaneous resolution.

Treatment is by excision and biopsy of the lesion; squamous cell carcinoma is found in approximately one quarter of the lesions biopsied.

D Nevi (moles)

Overview

Nevi are pigmented lesions of the skin that frequently concern the patient because of the fear of malignancy. Because the average white man has 15–20 nevi, total excision is unreasonable.

Clinical diagnosis is important, because malignant transformation can occur. In general, however, malignant transformation is rare in children. Also, well-circumscribed lesions and lesions with a uniform color rarely progress to malignancy.

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Suspicious -looking lesions should be biopsied by excision with a margin of normal skin.

Benign pigmented lesions

Junctional nevi are dark, flat, smooth lesions, which range generally from 1–2 cm in diameter. They are occasionally hairy and develop from the basal layer of epidermis. Nevi that are located on the palms and soles are usually junctional. They can develop into malignant melanoma, but this rarely

occurs before puberty.

Compound nevi are brown-to -black, well-circumscribed lesions that are usually less than 1 cm in diameter. They may be elevated and are frequently hairy, arising from the epidermal–dermal interface and from within the dermis. Malignant transformation is rare.

Intradermal nevi are light -colored, well-circumscribed lesions less than 1 cm in diameter. Hairs are usually present, and the cell distribution occurs in the dermis. Malignant transformation is rare.

Giant pigmented nevi

These brown-to -black, hairy lesions have an irregular nodular surface. They frequently involve

more than 1 ft2 of body surface and arise from the dermis and junctional areas. The lesions are frequently described, in terms of distribution, as “bathing trunk,” “vest,” “sleeve,” or “stocking.”

Malignant degeneration has been estimated at approximately 10%.

Excision with a margin of normal tissue is indicated, either in stages or with flap reconstruction.

Blue nevi are smooth, hairless lesions measuring less than 1 cm in diameter. They arise in the dermis, and malignant degeneration is rare.

Spitz nevi (benign juvenile melanomas) are smooth, round, pink -to -black lesions measuring 1–2 cm in diameter. They have increased cellularity and occur in nests within the upper dermis. Malignant degeneration is rare.

Nevi must be distinguished from freckles (ephelides). These pigmented lesions occur in the basal and upper dermis and have no malignant potential.

Treatment

Treatment is indicated for junctional and giant pigmented nevi because of their malignant potential.

Indications for excision of any pigmented lesion include:

Changes in color, size, shape, or consistency

Pain

Satellite nodules

Regional adenopathy

Except for large lesions, excisional biopsy, with a margin of normal skin, should be performed. Further therapy may be indicated, depending on the histologic diagnosis and location of the lesion.

For large lesions, a full -thickness wedge biopsy, including a small area of normal skin, should be taken.

E

Malignant melanoma (see Chapter 19, X B ) is a melanoblastic tumor that may develop in the skin or eye.

Epidemiology. The incidence is approximately 13 new cases per 100,000 population a year, representing

an increase of 50% in the past decade. The tumor occurs most commonly in the fifth decade of life, and the incidence is approximately equal in men and women.

Etiology. Exposure to sunlight appears to be an initiating event in the development of melanoma, and fairskinned white people with frequent direct (overhead) exposure to the sun are most often affected.

Detection of melanoma is determined by changes in the color, size, or shape of a nevus.

Men are most frequently affected on the back, chest, and upper extremities.

Women are most frequently affected on the back, lower extremities, and upper extremities.

Classification of melanomas is based on their gross and histologic appearance.

Superficial spreading melanoma accounts for 70% of all melanomas. It can be present on any area of the body but is found most frequently on the back and legs. The median age at

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diagnosis is the fifth decade. The tumor has irregular borders with a varied color pattern. Cell distribution is in the upper dermis with lateral junctional spread. Generally, the prognosis is good.

Nodular melanoma accounts for 15% of melanomas and occurs most commonly in the sixth decade of life. The tumor is blue-black and may be found on any area of the body. Spread is primarily vertical with rapid dermal invasion, and the prognosis is poor.

Acrolentiginous and mucosal melanomas make up 10% of all melanomas. They occur most commonly in the fifth decade of life and are distributed on the mucous membranes, palms, and soles. Irregular borders are common; lesions are generally black but may be amelanotic. Growth occurs slowly in a radial direction; cells are mainly in the upper dermis with occasional deep invasion. The prognosis depends on the depth of invasion and is between that of superficial spreading and nodular melanomas.

Lentigo maligna (melanotic freckle of Hutchinson) is the least common of the melanomas, and it appears most frequently in the seventh decade of life. The lesions are brown-black and contain elevated nodules within a smooth freckle. They occur most frequently on the head, neck, and hand. Growth is slow and in a radial direction, with cells in the upper dermis; vertical extension is infrequent. The prognosis is excellent.

Staging. Classification of the lesion is imperative for optimal treatment. Histologic evaluation with regard to the depth of invasion as well as the type of tumor is important for determining prognosis. To complete the staging, a thorough history and physical examination are necessary, including a complete blood count, 12 - test sequential multiple analysis (SMA-12), urinalysis, and chest radiograph.

Clark's classification assesses the level of invasion and has been adopted by the American Joint Committee for Cancer Staging and End Results.

Level I: The tumor is confined to the epidermis.

Level II: The tumor invades the papillary dermis.

Level III: The tumor fills the papillary dermis but does not invade the reticular dermis.

Level IV: The tumor invades the reticular dermis.

Level V: The tumor invades the subcutaneous fat.

Breslow's method is an additional method that is sometimes used. It involves measuring the depth of invasion precisely in millimeters. However, erroneous estimates of the depth of invasion can occur if ulceration is present.

Patients with Clark's level I, II, or III lesion and with a depth of invasion that is less than 0.76 mm are at low risk for metastasis.

Patients with lesions at level IV or V and with a depth of invasion greater than 1.5 mm are at high risk for distant spread.

Treatment depends on the depth of invasion. Biopsy is by total excision when feasible; otherwise, incisional biopsy is performed. Frozen section is inaccurate in determining the depth of invasion.

Excision. There is debate over the previously accepted 5-cm margin.

For melanoma in situ, 0.5 cm margins are indicated.

For lesions less than 1.0 mm in thickness, a 1-cm margin is generally sufficient.

For lesions 1–4 mm in thickness, 2-cm margins are indicated. The need to excise the underlying fascia is debatable.

For lesions more than 4 mm in thickness, 3-cm margins are indicated.

Lymph node removal

Clinically involved regional lymph nodes with level II, III, IV, or V disease should be resected with an elective lymph node dissection (ELND), which in the case of melanoma entails resection of level I, II, and III lymph nodes.

Sentinal node biopsy is a minimally invasive way of staging clinically occult regional lymph node metastases. Several hours prior to surgery, the area adjacent to the primary lesion is injected with a radiotracer (technetium sulfur colloid) for lymphoscintigraphy in the radiology department for lymph node localization intraoperatively. A visible (isosulfan blue) dye is also injected perioperatively near the lesion. The lymph node(s) in the regional node basin that first takes up these tracers is considered the sentinal node. It is

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excised and examined for disease. The sentinal node biopsy is useful in that it prevents unnecessary ELND and the associated morbidity. If the sentinal node if free of disease, the patient is spared an ELND.

Postoperative morbidity from lymph node resection needs to be considered when lesions involve the face or lower extremities.

Adjuvant therapy is recommended by some authors to prolong the diseasefree interval.

Regional hyperthermic perfusion involves isolating the blood supply of a limb with a pump oxygenator, enabling high doses of chemotherapy to be delivered to the limb at elevated temperatures (40°C) without the side effects of systemic toxicity. The role of this treatment has yet to be clarified.

Chemotherapy with dacarbazine (DTIC), carmustine (BiCNU), and lomustine (CeeNU) has not significantly altered the course of disease.

Immunotherapy is useful for the control of cutaneous metastases, but visceral metastases have not responded to any significant degree.

Radiotherapy is strictly palliative and has been used for brain and bone metastases.

Prognosis is related to the status of the regional lymph nodes. When disease is confined at the primary site, the 5-year survival rate is approximately 80%–90%. If regional lymph nodes are involved, this figure drops to 30%–50%. Patients with distant or visceral metastases usually die within 12 months.

F

Other malignant tumors of the skin commonly occur in exposed areas. Generally, they are low -grade tumors and metastasize late. For this reason, they are highly curable.

Basal cell carcinoma (see Chapter 19, X A ) is the most common skin tumor seen. It is localized and grows slowly, and it generally occurs in the head and neck. It is found most commonly in individuals of northern European descent.

Etiology. Basal cell carcinoma has also been associated with xeroderma pigmentosum, basal cell nevus syndrome, nevus sebaceus, and unstable burn scars. With the advent of radiation therapy, basal cell carcinomas are being seen with increasing frequency in areas of dermatitis.

Clinical presentation. The lesion has pearly, translucent edges, which may become erythematous or pigmented. Frequently, a visible telangiectasia is present. As the lesion grows, it may ulcerate and eventually invade underlying structures. Morphologic types of basal cell cancer include superficial, nodular, pigmented, and morphealike (sclerosing). Metastatic disease is rare.

Treatment involves the complete removal of the tumor to achieve a cure. Biopsy is mandatory to establish a pathologic diagnosis.

Curettage and electrodesiccation result in a 95% cure rate, and the technique is acceptable for lesions less than 2 cm in diameter. The disadvantage is the lack of a specimen for determining the adequacy of resection.

Radiation therapy can be used in areas where tissue preservation is important (e.g., the eyelids). The cure rate is approximately 90%. The disadvantages are that depigmentation and skin atrophy can occur with time.

Excision with primary closure results in a cure rate of approximately 95% and allows inspection of the specimen for adequate margins. If necessary, reconstruction can be performed at the same sitting.

Mohs' micrographic surgery involves tumor mapping to determine the adequacy of resection. Generally, it is most applicable to recurrent tumors, morphealike tumors, and those of the nose or perinasal areas. As cure rates approach 99%, immediate reconstruction can achieve excellent esthetic results.

Cryotherapy is acceptable in certain cases. It has a higher morbidity, and scarring is less predictable than with other techniques.

Topical chemotherapy results in unacceptable cure rates.

Recurrent disease requires wide re-excision.

tendency to metastasize or to invade locally.

Clinical presentation. These tumors usually present as an enlarging mass, which is frequently painless. If they occur in deep locations, such as the retroperitoneum, they are often quite large at the time of diagnosis.

Diagnosis is made on permanent sections of a representative biopsy. MRI is helpful in determining the extent of the tumor. The biopsy should be planned with the future surgical procedure in mind. Excisional biopsy is indicated for lesions less than 3 cm in diameter; otherwise, incisional biopsy is indicated.

Treatment. These tumors are frequently treated inadequately because they have a pseudocapsule, which may lead the surgeon to assume falsely that all of the tumor has been removed. In reality, these tumors extend along tissue planes well beyond their apparent margins.

Wide local excision or amputation is the current accepted treatment. Chemotherapy and postoperative radiotherapy are frequently indicated.

Limb-sparing surgery is indicated when wide local excision can be accomplished without jeopardizing the function of the extremity (i.e., involvement of major nerves or vessels).

Limited surgery with high -dose radiotherapy yields a local recurrence rate similar to that for radical surgery (20%–50%).

The route of metastasis is usually hematogenous , and the lungs are the most frequent site of involvement. Lymphatic spread occurs less often and usually late in the course of the

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disease. Metastatic lesions in the lungs should be resected if the primary tumor is under good control and there is no evidence of other sites of involvement.

Major soft tissue sarcomas

Liposarcoma is the most common of the soft tissue sarcomas in the adult.

Only 1% arise from pre -existing benign lipomas.

Liposarcomas can occur in any area, including the retroperitoneum.

They are treated by wide excision. The tumors are radiosensitive, and radiotherapy may be helpful in locations where wide excision is not possible.

Well -differentiated lesions have a 70% 5-year survival rate, whereas poorly differentiated lesions have only a 20% survival rate at 5 years.

Fibrosarcoma is the second most common soft tissue sarcoma in the adult.

These lesions are usually found in an extremity, where they present as a hard, round mass. They are more common in men than in women and are the most common sarcoma found in black persons.

They are radioresistant, and the treatment is wide excision. Fibrosarcomas are very susceptible to local recurrence and must be treated aggressively at the time of presentation.