Hyalinizing Clear Cell Carcinoma of the Lung With Uncommon Distant Cutaneous Metastasis and Aggressive Clinical Course.

Hyalinizing clear cell carcinoma (HCCC) is a rare tumor. Most lesions arise in the salivary gland; however, other primary sites include the nasal and oral cavities, and rarely lung. Lesions are characterized by tumor lobules with pale or clear cytoplasm, arranged in nests or cords, surrounded by a mixed hyalinized and fibrocellular stroma. EWSR1-ATF1 gene fusion is often reported in these lesions. Typically, HCCC bears a good prognosis. We report a unique case of primary lung HCCC (PLHCCC) with cutaneous metastasis and aggressive clinical course. To the best of our knowledge, cutaneous metastasis by PLHCCC has not been previously observed and may signal an aggressive clinical course with poor prognosis.