LARGE CELL NEUROENDOCRINE CARCINOMA OF THE LUNG: A CLINICAL CARE CONUNDRUM

SESSION TITLE: Lung Cancer Case Report Posters 16 SESSION TYPE: Case Report Posters PRESENTED ON: 10/09/2023 02:10 pm - 02:55 pm INTRODUCTION: Pulmonary large cell neuroendocrine carcinoma (LCNEC) is a rare and aggressive tumor with an overall prevalence of 0.3%-3% of all primary lung cancers. It is a highly aggressive cancer and shares similarities with both small-cell and non-small-cell lung cancer. Due to its rarity, there is no standardized treatment. Most of the patients present as locally advanced or advanced disease. We hereby present a case of early stage pulmonary LCNEC who was managed with surgery and adjuvant chemotherapy. CASE PRESENTATION: A 54-year-old female with a 22-pack year smoking history presented to the ED after a syncopal episode. CT Chest with PE protocol revealed an incidental 2.7cm solitary irregular solid noncalcified right lower lobe pulmonary nodule with no mediastinal or hilar lymphadenopathy. Patient was diagnosed with vasovagal syncope secondary to dehydration and treated with IV fluids. Outpatient PET/CT scan revealed hypermetabolic 30mm mass in the superior segment of the right lower lobe likely representing primary lung carcinoma and no evidence of metastasis. Bronchoscopy with EBUS lung biopsy showed large tumor cells with features consistent with poorly differentiated neuroendocrine carcinoma with large cell morphology and positive TTF-1, CD56, synaptophysin and AE1/AE3 keratin. Patient underwent right lower lobectomy and mediastinal lymph node dissection. Final pathology showed stage IA3 (T1cN0M0) pulmonary LCNEC. Adjuvant chemotherapy with cisplatin and etoposide was planned. DISCUSSION: Pulmonary LCNEC was first described by Travis et al., is a rare and highly aggressive cancer. 25% of patients present as early stage (I-IIIA), 20% as locally advanced (Stage IIIB-C) and 40-50% as metastatic disease. It has poor prognosis with an overall 5-year survival rate of less than 20%. LCNEC is minimally symptomatic and predominantly seen in elderly men with extensive smoking history. The diagnosis requires a combination of histopathological and immunohistochemical examination. It is characterized by the presence of large cells with neuroendocrine differentiation as described in our patient's histology report. Immunohistochemistry is positive for CD56 and synaptophysin indicative of neuroendocrine origin, Pan-Cytokeratin antibody AE1 and AE3 indicative of epithelial origin consistent with NSCLC, and positive for TTF-1 confirming tumor's primary lung origin. Based on retrospective data, surgery for early stage LCNEC improves survival and adjuvant chemotherapy +/- radiation further improves prognosis. Advanced stages have overall poorer prognosis compared to early stage and treatment is chemotherapy with platinum-based regimen, similar to small cell lung cancer (1-3). CONCLUSIONS: Pulmonary LCNEC is a rare and aggressive subtype of lung cancer with a poor prognosis. Early diagnosis and prompt treatment with surgery and adjuvant multimodality treatment with chemotherapy +/- radiation may improve survival in selected patients. However, given the high rate of recurrence and overall poor prognosis than other types of lung cancer, the development of new treatment strategies is warranted. REFERENCE #1: Iyoda, A., Hiroshima, K., Toyozaki, T., Haga, Y., Fujisawa, T., & Ohwada, H. (2001). Clinical characterization of pulmonary large cell neuroendocrine carcinoma and large cell carcinoma with neuroendocrine morphology. Cancer, 91(11), 1992–2000. https://doi.org/10.1002/1097-0142(20010601)91:11<_x0031_992:_x003a_aid-cncr1224>3.0.co;2-5 REFERENCE #2: Travis, W. D., Linnoila, R. I., Tsokos, M. G., Hitchcock, C. L., Cutler, G. B., Jr, Nieman, L., Chrousos, G., Pass, H., & Doppman, J. (1991). Neuroendocrine tumors of the lung with proposed criteria for large-cell neuroendocrine carcinoma. An ultrastructural, immunohistochemical, and flow cytometric study of 35 cases. The American journal of surgical pathology, 15(6), 529–553. https://doi.org/10.1097/00000478-199106000-00003 REFERENCE #3: Yang, L., Fan, Y., & Lu, H. (2022). Pulmonary Large Cell Neuroendocrine Carcinoma. Pathology oncology research : POR, 28, 1610730. https://doi.org/10.3389/pore.2022.1610730 DISCLOSURES: No relevant relationships by Haytham Adada No relevant relationships by Camelia Chirculescu No relevant relationships by Ibrahim Nakhoul No relevant relationships by Ayan Novruzov No relevant relationships by Deepali Pandey No relevant relationships by Thomas Soike No relevant relationships by MRIDULA TALARI