Asymptomatic Pulmonary Melanoma. An Incidental Finding While Evaluating New Onset Cough
Introduction Malignant melanoma in the respiratory tract is very seldom primary, accounting for 0.01% of the lung malignancies. It often presents as a solitary mass provoking mass effect and/or obstructive symptoms. It is most commonly seen in patients older than 50 years old, with no gender predilection. Complete surgical excision is the treatment of choice. Additionally, chemotherapy or radiation might be necessary, depending on tumor location and/or metastasis status. Case Presentation A 76 year old non-smoker male with history of Obstructive Sleep Apnea presented for elective a Left Knee Total Arthroplasty. After a successful intervention the patient develoved a non-productive continuous cough. A Chest X-Ray (CXR) was obtained and showed a nodular, irregular opacity in the right lung. Computerized Tomography (CT) of the Chest followed and demonstrated a 3.2x2x4.3 cm mass in the superior segment of the right lower lobe as well as a 1.6 cm subcarinal lymph node. A Positron Emission Tomography (PET) Scan revealed activity in the right lower lobe on both, early and delayed imaging. Biopsy revealed an invasive, poorly differentiated, malignant melanoma. He was instructed to follow with pulmonary medicine after discharge. Two months later, he underwent elective bronchoscopic wedge resection of the right lower lobe with lymph node dissection. No chemotherapy or radiation was indicated. Serial Repeat CXR and CT Scans have shown stable postoperative changes but no signs of recurrence. To date, the patient continues to follow with his pulmonologist every 6 months for surveillance visits. Discussion Malignant melanoma is an extremely rare and aggressive non epithelial neoplasm of melanocytes. If detected and treated in early stages (1 and 2) survival rates range from 70-95% at 5 years; whereas stages 3 and 4 range from 15-35% only. There are no identified risk factors The novelty of this case is threefold. First , the incidence of Primary Pulmonary Melanoma (PPM) in non-smokers is exceptionally rare. To date, there are only two cases described in the literature. Secondly, at the time of diagnosis, this malignancy was determined to be stage 3, meaning more than 70% probability of death within one year nevertheless our patient has survived for almost 4 years. Finally, PPM has either airway obstructive or systemic malignancy related symptoms at the time of diagnosis (even those diagnosed at stage 1), our patient belongs to a very rare group of patients in which there are no symptoms at all when this cancer is detected.
Figueroa Rodriguez F, Uddin A, Nasr J. Asymptomatic pulmonary melanoma. An incidental finding while evaluating new onset cough. American Journal of Respiratory and Critical Care Medicine 2019;199:A7007