PRIMARY PULMONARY COLLISION TUMOR WITH ADENOCARCINOMA AND SCLC

Abstract

SESSION TITLE: Lung Cancer 3 SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: 10/09/2018 01:15 PM - 02:15 PM INTRODUCTION: A collision tumor is defined as two histologically independent malignant neoplasms within the same organ. Our case presents a 78 year-old man with heavy smoking history that presented with 1 week long history of productive cough and shortness of breath. Imaging revealed a large pleural effusion; a spiculated left lung mass, fluid analysis positive for mixed adenocarcinoma and small lung cell carcinoma and pleural histology showed small lung cell carcinoma. CASE PRESENTATION: A 78-year-old man was brought to the emergency department with 1 week history of productive cough and shortness of breath. He reported unintentional 60 lbs weight loss over the 2 months, and reported heavy smoking history since he was 7 years-old. Physical exam and imaging were consistent with large left pleural effusion and consolidation of the left upper and left lower lobes. Pleural fluid chemistry suggested exudative effusion, and cytology revealed metastatic mixed adenocarcinoma and small cell carcinoma consistent with lung primary tumor. He underwent pleural biopsy, talc pleurodesis and partial decortication. Pleural histology was positive for small lung cell carcinoma. DISCUSSION: Collision tumors are rare entities, defined as two or more histologically distinct malignant neoplasms developing in the same organ [1]. There are 3 main tumorigenesis theories that explain the pathophysiology. The first one considers the accidental meeting of coexisting malignancies developing in the same organ, the second one considers a single carcinogen that precipitates two distinct neoplasms that collide, and the third theory is the tumor-to-tumor carcinogenesis, in which one neoplasm induces the second primary [2]. Clinical data has suggested that some of these collision tumors are developing from a single cell that eventually differentiates into distinct types and on the other hand our patient does have a strong smoking history and would likely be the carcinogenic stimulus [2, 3]. The relative risk of lung cancer in smokers of 20 or more cigarettes a day is 20 to 30 times higher than in nonsmokers [3]. Small Cell Lung Carcinoma is the histopathological subtype most commonly associated with smoking and adenocarcinoma most commonly seen in nonsmokers [3].Prognosis is dependent on the cytological grading of each neoplasm, and staging, which is highly undifferentiated and advanced in our patient [3]. When brain metastases are present, without treatment, the median survival is about 1-2 months. Whole brain radiotherapy (WBRT) is the mainstay of treatment with median survival between 3-6 months. CONCLUSIONS: Collision tumor of the lung with multiple primary lung neoplasms is a rare occurrence. It is mostly diagnosed port operatively after histological diagnosis and classification. Due to its very low incidence, this case is meant to bring awareness of cancer behavior, tumorigenesis, differentiation, and adhesion. Reference #1: Suzuki, Shigeki, T. Ohtsuka, T. Hato, et al., “Primary pulmonary collision tumor with three components in the underlying interstitial lung disease,” Thoracic Cancer, vol. 5, no. 5, pp 460-462, 2015. Reference #2: Michalinos, Adamantios, A. Constantinidou, M. Kontos, “Gastric collision tumors: An insight into their origin and clinical significance,” Gastroenterology Research and Practice, vol. 2015, Article ID 314158, 8 pages, 2015. https://doi.org/10.1155/2015/314158 Reference #3: Nakata, Shoji, Y. Nagata, M. Sugaya, et al., “Primary pulmonary collision cancer consisting of large cell carcinoma and adenocarcinoma,” Annals of Thoracic Surgery, vo. 2008, no. 80, pp 340-2. DISCLOSURES: No relevant relationships by Sandra Donahue, source=Web Response No relevant relationships by Anoopa Gollapudi, source=Web Response