Dx: SCC of the lungs with skin metastases
Our patient’s chest radiograph—which revealed a left pulmonary mass—combined with her blood work and lesional biopsies, led us to diagnose primary squamous cell carcinoma (SCC) of the lung with skin metastases.
Approximately 30% of all lung cancers are classified as SCC.1 Pulmonary SCC metastatic to the skin tends to remain localized within the skin in the areas of the abdomen, anterior chest, back, scalp, and neck.2-6 Though cutaneous metastases of internal malignancies occur in 0.7% to 9.0% of all cancer patients, the incidence of skin metastases from lung cancer ranges from 1% to 12%.6-8
Lesions are painless and moveable
Most cutaneous metastases consist of single or multiple lesions that are painless, movable, and nonspecific. These lesions may also be firm to palpation, ulcerated, or exudative and able to penetrate the dermis or subcutaneous layer of skin with intact overlying epidermis.7-9
Skin eruptions may be the first sign of trouble
Prompt identification and diagnosis of these lesions are tantamount in tumor staging and therapy.
Schwartz reported that “in a series of patients with skin metastases seen in dermatologic consultation, the underlying cancer had been undiagnosed in 60% with lung cancer, in 53% with renal cancer, and in 40% with ovarian cancer.”7 Similar findings have been reported elsewhere.4,8 Thus, metastatic carcinoma to the skin should always be included in the differential diagnosis for newly eruptive skin lesions, regardless of whether the patient has ever been diagnosed with any form of cancer.10