White : Diseases of the Skin - Lymphomas, Metastases and Other Malignant Tumors

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Gary M. White & Neil H. Cox

Diseases of the Skin

33	Lymphomas, Metastases, and Other Malignant Tumors

CUTANEOUS METASTASES

Cutaneous manifestations of internal cancer include the following.

•	Various cutaneous paraneoplastic eruptions (Ch.12).
•	Direct extension to the skin (e.g. from breast cancer, Figs 33.42, or Paget disease) or seeding along needle biopsy wounds.
•	Indirect involvement such as lymphatic obstruction (which may be accompanied by retrograde lymphatic spread of tumor).
•	Metastasis from the internal tumor.

    Cutaneous metastases may be the presenting sign of a tumor or the first sign of metastatic disease, and overall (including autopsy data) occur in 510% of patients with internal malignancy (Figs 33.43 - 33.48). They generally infer a poor prognosis. Cutaneous metastases usually present as enlarging plaques and nodules; less common variants such as carcinoma en cuirasse (scleroderma-like), carcinoma erysipeloides (inflammatory metastatic carcinoma), and carcinoma telangiectoides may cause diagnostic difficulty.
    The types of cancer that cause skin metastases generally correlate with the relative frequency of tumors in the two sexes, thus metastases from bronchial carcinoma are the most frequent in men (accounting for about a quarter of cases of cutaneous metastasis in men) and those from breast carcinoma are the most common (about two-thirds of cases) in women. The clinical appearance of the metastasis is generally not helpful in determining the tumor type, unless there are specific features, such as blue-black pigmentation in melanoma (probably the second commonest cause of skin metastases in either sex). Annular metastases seem to be most frequently associated with breast or ovarian tumors, and metastases from renal carcinomas may be highly vascular and have a predilection for scalp and head, but none of these are reliable indicators
of the site of origin.
    Specific sites of cutaneous metastasis are of variable help in localizing the primary tumor. Sites worthy of special mention include the following.

•	Umbilicusmetastases at this site are known as Sister Mary Joseph nodule (Figs 33.48). They are most commonly due to bowel, urinary tract, or female internal genital cancers, and generally occur in association with widespread intraabdominal neoplasia.
•	Lower abdominal wall or perineumcutaneous metastases from the prostate or bladder are often localized to this area.
•	Breastbreast carcinoma metastases to skin are often on the upper chest wall.
•	Scalp - metastases to the scalp are overrepresented in referrals to dermatologists, as they may be confused with cysts or alopecia; such metastases generally represent hematogenous spread and may be from many primary sites. The commonest tumor to metastasize to scalp is bronchial carcinoma; however, it is also a site of predilection for metastases from thyroid or renal carcinoma. Scalp metastases are often an early sign of metastatic disease.
•	Scars - occasionally, metastases ?rst appear in a recent scar, even if physically unrelated to the tumor (such as a skin graft donor area, or in the line of a chest drain); scar metastases may represent an effect of high vascularity, similar to that seen in the scalp.

Figure 33.42 (a) Primary breast cancer may affect the skin by direct involvement, or may cause puckering due to retraction of the underlying skin. (b) Recurrent carcinoma of the breast may also cause direct involvement of the skin. Treatment options in such cases may be limited, as most such patients have already had radiotherapy to the affected region.

Fig 33.43 Cutaneous metastasis on the nose, resembling a primary skin neoplasm but with rapid growth and pain. This was the presenting feature in a patient whose investigations revealed multiple internal metastases.

Fig 33.44 Metastases from bladder or prostate (as in this case) tend to affect the lower abdomen. This broad area also demonstrates lymphedema due to lymphatic obstruction. (Courtesy of the Department of Dermatology, University of California , San Diego .)

Figure 33.45 Isolated vascular-appearing metastases in a patient with renal carcinoma. The scalp is a classic site for renal tumor metastases, although most metastatic nodules on the scalp will prove to be from breast (women) or lung (men) carcinoma.

Fig 33.46 Metastases from breast carcinoma are not uncommon, although both patterns illustrated here are relatively unusual. (a) A large, ?rm plaque on the scalp, a pattern termed alopecia neoplastica. (b) Multiple subcutaneous nodules in a patient with non-speci?c malaise and a previously undiagnosed breast carcinoma.

Fig 33.47 Metastatic lesions may be clinically bizarre. This pattern of symmetric metastasis to the tips on the fingers was from carcinoma of the esophagus, and presumably represented hematogenous spread of tumor.

Fig 33.48 Sister Mary Joseph nodule. Sister Mary Joseph was a nurse at the Mayo Clinic who noticed that patients with abdominal cancers sometimes developed metastases at the umbilicus.

Fig 33.49 Paget disease of the nipple, in this case clinically con?ned to the nipple. The main differential diagnosis is from eczema of the nipple, which is common in atopic individuals but is bilateral.

Figure 33.50 (a) Paget disease affecting the areola, again strictly unilateral. (b) By contrast, this patient with eczema on the breast has sparing of the nipple and areola. (Panel b courtesy of Dr. G. Dawn.)

In children, cutaneous metastases are rare, but the tumor types differ from those of adults. Lymphoma, leukemia, histiocytoses, and neuroblastoma are the most frequent tumors to involve the skin in children. Neuroblastoma metastases usually have a bluish color; due to their catecholamine content, they develop local blanching if rubbed or stroked.

Treatment
Treatment of cutaneous metastases is generally by chemotherapy and supportive care appropriate for the primary tumor type and stage, as there are usually metastases in other organs. Local treatment options include radiotherapy, excision, laser ablation, cryotherapy, intralesional chemotherapy, photodynamic therapy, and others, depending on the tumor type, the degree of symptoms, and complications such as ulceration.

PRACTICE POINTS

•	Skin nodules with new-onset itch or ichthyosis should always raise the possibility of systemic lymphoma or of metastasis from an internal tumor.
•	Scalp ´cysts´ with alopecia of the overlying skin in an adult should raise the possibility of metastases: the scalp is involved with disproportionate frequency.
•	Any new red papulonodule present for more than 2 months and enlarging, and for which a clinical diagnosis cannot be made, should be biopsied.