Metastasis of lung cancer to the finger: a report of two cases

Abstract

Case 1 A 73‐year‐old man complained of a 2‐month history of an asymptomatic nodule on the left thumb. The nodule had enlarged gradually and was accompanied by tenderness. The nodule on the tip of the left thumb was about 1 cm in diameter, well demarcated, fleshy, and reddish, with a granulomatous appearance (Fig. 1a). Histopathologic findings of the digital nodule revealed a dense dermal infiltration of cells with a marked nuclear atypicality, cell keratinization, and intercellular bridges (Fig. 1b). Because the diagnosis of a metastatic carcinoma of the skin was suspected, subsequent systemic examination was considered. Computed tomography revealed the presence of a primary carcinoma in the left lung, which was diagnosed as squamous cell carcinoma, T4N0M1, stage IV, and there were multiple metastases. The histopathologic finding of the digital nodule was similar to that of the lung lesions. The patient underwent radiation therapy for the digital tumor, and systemic chemotherapy which was stopped because of adverse side‐effects. The patient died 6 months after identification of the tumor.(a) Clinical appearance of Case 1. Tumor on the tip of the left thumb. (b) Histopathology of the tumor of Case 1 showing dense dermal infiltration of the cells, with marked nuclear atypicality, cell keratinization, and intercellular bridges (hematoxylin and eosin staining; original magnification, × 40)imageCase 2 A 71‐year‐old man presented with a nodule on the left ring finger 1 month after operation for cancer of the left lung. Pathologic findings of the lung revealed a moderate or highly differentiated squamous cell carcinoma with cell keratinization, pT2N1M0, stage II. The finger tumor gradually enlarged in size. Physical examination showed an approximately 2 cm in diameter, elastic, hard, relatively well‐demarcated, and hyperkeratotic tumor on the tip of the left ring finger (Fig. 2a). The lesion was accompanied by erosions in its center and a dark, erythematous swelling at the surrounding edges. A skin biopsy of the digital tumor was taken. Histologic examination revealed a dense dermal infiltration with marked nuclear atypicality and a tendency to keratinize. Squamous cell carcinoma with moderate or high cell differentiation was pathologically diagnosed (Fig. 2b), the same as recognized in the lung cancer specimen. This case was diagnosed as metastatic carcinoma to the finger, associated with primary lung cancer.(a) Clinical appearance of Case 2. Tumor on the tip of the left ring finger with an erosion at its center and an erythematous swelling at the surrounding edges. (b) Skin biopsy from the nodule of Case 2 showing the proliferation of marked atypical squamous cells in the dermis and keratinization of the cells (hematoxylin and eosin staining; original magnification, × 40)image