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A4005 - Primary Pulmonary Melanoma
Author Block: S. Ossowski1, M. Thinn2, J. Moyers3; 1Internal Medicine, LLUMC- Internal Medicine, Loma Linda, CA, United States, 2Internal Medicine, Loma Linda VA Healthcare, Loma Linda, CA, United States, 3Hematology and Oncology, LLUMC, Loma Linda, CA, United States.
Introduction: Melanoma arises from melanocytes with >90% of cases arising from the skin, but has been known to also be found on mucosal surfaces. There are 41,000 deaths related to melanoma per year, and 160,000 new cases of melanoma per year. 1 Primary pulmonary malignant melanoma is melanoma of the lung without evidence of extra-pulmonary disease. It is a nonepithelial neoplasm representing 0.01% of primary lung tumors. 1 It is thought to arise from melanoblasts in the respiratory tract.2 Primary malignant melanoma of the lung most commonly metastasizes to the brain and liver, not unlike other primary pulmonary malignancies.3
Case: A 71 year old male with COPD (FEV1/FVC = 56%) presented with initially suspected pneumonia unresponsive to two courses antibiotic therapy. CT showed 7.5X5.3cm right lower lobe mass. Biopsy showed a necrotic mass with immunohistochemical stains strongly positive for S100, melan A, and HMB-45 (melanocytic markers) diagnostic of melanoma. He was also found to be BRAF V600E mutation negative. PET-CT showed right lower lobe pleural based mass, hilar, mediastinal, supraclavicular and cervical lymphadenopathy without a primary skin lesion. Patient began to have hemoptysis and was transferred to the ICU. Because he was not a surgical candidate due to his high risk pulmonary disease, embolization was attempted but failed due to difficultly advancing the microcatheter due to an anatomical variance. He then underwent palliative radiation with 8 Grey in a single fraction directed at the tumor site. He responded well to the radiation, and his hemoglobin stabilized and hemoptysis subsided. He underwent thorough skin examinations by dermatology and funduscopic examinations by ophthalmology, but no primary melanoma could be found. He has subsequently been started on immunotherapy with involumab and ipilimumab.
Discussion: Melanoma presenting as a lung mass is rare. There are only 40 cases reported to date of in the English literature. Because of the rarity of this malignancy, there is a paucity of data to guide treatment, although most studies revealed survival benefit from surgical resection, largely before the advent of immunotherapy.3 This case demonstrates the use of embolization and radiation for patients with hemoptysis and primary malignant melanoma of the lung, which is not well studied in this population. Radiation, as well as immunotherapy, are alternative therapies for patients, who are poor surgical candidates or have lesions anatomically incompatible with surgery, and can improve overall survival.4,5