Cutaneous metastases of internal neoplasms are rare. They can often be the first clinical manifestation of an occult malignancy and harbingers of advanced disease. Lung cancer, which often metastasizes to brain, liver, bone and adrenal gland, is responsible for majority of skin metastasis in men and is second only to breast as a source in women.
A 77-year old white man presented to clinic, having developed several painful “lumps” all over his body during a 4 month period. In addition, he noted exertional dyspnea, dry cough and a 50 lb weight loss. He denied fevers or night sweats but had a dull headache for several weeks. He was a 120 pack year smoker with an otherwise unremarkable past medical history. Physical examination revealed a cachectic male with pulse of 82 beats/min, BP 166/96 mm Hg, temperature of 97.7 F, and respiratory rate of 18 breaths/min. He had no clubbing or palpable lymphadenopathy. Chest examination revealed no wheezes or crackles. Pertinent clinical findings included several 1-3 cm firm and mobile subcutaneous nodules, mainly over the upper extremities, trunk, and abdomen. They were exquisitely tender but had no overlying skin discoloration or breakdown. The patient had no neurological deficits.Pertinent laboratory data included hemoglobin of 12.7 g/dL and room air arterial blood gas of pH 7.479, pCO2 33.8 mm Hg, pO2 48.0 mm Hg and SaO2 88 %. BUN, creatinine and LFT’s were within normal limits. Chest radiograph revealed a left hilar mass with patchy alveolar opacities involving the left upper lobe. CT scan of the chest demonstrated a large mass with varying densities surrounding the lower trachea and left mainstem bronchus, completely occluding the left pulmonary artery. A brain MRI showed numerous lesions in the cerebellum, right thalamus and right occiput. Bone scan showed widespread metastatic lesions.A diagnosis of extensive stage small cell lung cancer with skin metastases was made following excisional biopsy of a subcutaneous nodule and bronchoscopic needle aspirate of the mediastinal mass.
Although cutaneous metastasis from lung cancer is rare, it may be the first clinical manifestation of occult cancer. Cancers that metastasize to other organs, also involve the skin. While lung cancer is the commonest cause of skin metastasis in men, it is second only to breast cancer in women. Other tumors involving the skin include cancers of the oral cavity, colon, ovary and stomach. The incidence varies from 3-7 %. Most cutaneous metastases are firm, mobile, round, solitary or multiple and vary in size from 1-6 cm. While some are superficial, others may extend deep into the subcutaneous tissue. Skin discoloration or ulceration may be present. Skin metastases in lung cancer are commonly found in the chest, abdomen and back and rarely involve the scalp, face and extremities. Of all the lung cancers, adenocarcinoma and large cell carcinoma most commonly metastasize to the skin compared to small cell and squamous cell carcinoma. Skin metastases often herald a dismal outcome as they often are associated with widespread metastases with involvement of the liver, brain, bone and adrenal gland. Response to chemotherapy is poor. Median survival after diagnosis of skin metastases is approximately 4 months. Poor prognostic factors include non-resectability of primary tumor, small-cell lung cancer and multiple cutaneous or extracutaneous lesions.
It is important to recognize that skin metastases may be the first clinical manifestation of an occult malignancy. Biopsy specimens must be taken from all unexplained skin nodules in patients who smoke or who have a history of lung cancer. Survival after diagnosis of skin metastases associated with lung cancer is dismal. Our patient died within a week following diagnosis.
Sebastian Fernandez-Bussy, None.