Cutaneous Metastasis as the First Symptom: An Uncommon Presentation of Squamous Cell Lung Cancer

Correspondence To the Editor: Cutaneous metastasis of the internal malignancy is unusual. A previous study has revealed that the incidence of cutaneous metastasis is only about 1%. Lung cancer is considered to be one of the most frequent sources of skin metastasis, especially in males. Here, we reported a case with cutaneous metastases from squamous cell lung cancer. An 80‑year‑old male, a chronic smoker for 60 years with a past medical history of chronic obstructive pulmonary disease, was admitted to Beijing Chaoyang Hospital on July 21, 2015, for the symptom of fast‑growing multiple cutaneous nodules, which had developed over the past 2 weeks. The patient had occasional hemoptysis, but no dyspnea, fever, weight loss, and night sweats. The physical examination was normal except for multiple cutaneous lesions on the skin (one lesion each on the face, left index finger tip, right back, and left thumb fingertip and four on both lower limbs). The cutaneous lesions were of varying sizes (range: 0.5–3.0 cm) and were tender, firm, and growing from the subcutaneous tissue [Figure 1a and 1b]. The laboratory tests were unremarkable apart from the mildly elevated carbohydrate antigen 199 (32.6 U/ml; normal range: 0–30.9 U/ml). The chest computed tomography (CT) showed right lower lobe mass with an irregular cavity, bronchial stenosis, mediastinal and right hilar lymphadenopathy [Figure 1c]. The whole body 18 F‑fluorodeoxyglucose positron emission tomography/CT imaging showed hypermetabolic activities in the lower lobe of the right lung, mediastinal and right hilar lymph nodes, bilateral pleura, liver, spleen, bones, and multiple subcutaneous skin nodules [Figure 1d]. As the patient rejected bronchoscopy, the biopsies of skin lesions on the face and left index fingertip were performed first. Pathological and immunohistological examination of the specimens showed a cutaneous involvement of squamous cell carcinoma [Figure 1e and 1f]. The moderately well‑differentiated squamous cell carcinoma was confirmed by percutaneous lung biopsy afterward. Biopsy materials were immunohistologically negative for Napsin A and thyroid transcription factor‑1, and positive for cytokeratin 5/6, p40, and p63. This patient was diagnosed as squamous cell lung cancer with multiple distant organ metastases eventually. Unfortunately, he had given up further treatment and died one month later. Lung cancer is the most common cause of death by malignancy in China. Although the distant metastasis of lung cancer is usual, skin involvement is infrequent. The incidence of cutaneous metastasis in lung cancer is approximately 0.2–3.1%. [2] For different histologic types of lung cancer, …