A riddle wrapped in a mystery: mucoepidermoid carcinoma (mec) found during evaluation of persistent lung collapse

SESSION TITLE: Lung Cancer Imaging Case Report Posters 2SESSION TYPE: Case Report PostersPRESENTED ON: 10/19/2022 12:45 pm - 01:45 pmINTRODUCTION: Though rare, mucoepidermoid carcinomas (MEC) are primary salivary gland tumors that can result in airway obstruction of the lung [1,2] We present one such case in a young woman found to have persistent lobar collapse of the lung.CASE PRESENTATION: An 18-year-old female presented to the Emergency Department with progressive dyspnea and hemoptysis. She was admitted six months prior for necrotizing pneumonia with collapse of the right middle lobe (RML), right lower lobe (RLL), and concurrent empyema. Despite prolonged antibiotics and a chest tube, a computed tomography (CT) of the chest revealed persistent RML and RLL collapse. Bronchoscopy demonstrated a well circumscribed, nodular endobronchial mass in the bronchus intermedius (BI). On gross appearance, papilloma was suspected. Pathology after laser resection demonstrated inflammatory changes. All cultures were negative for bacteria and virus. She denied sexual activity. Approximately 1 week later, she presented with massive hemoptysis requiring intubation, an endobronchial blocker and embolization for stabilization. Repeat CT chest demonstrated an endobronchial lesion in the BI along with diffuse bronchiectasis throughout the RLL and RML. Once stable, repeat bronchoscopy and biopsy was conclusive for low grade mucoepidermoid carcinoma. Histopathology revealed squamous and mucinous cells positive for cytokeratin and p63, while negative for TTF-1. She has since undergone resection of her RML and RLL with lymph node dissection. Gross pathology demonstrated a 3.2 cm lesion in the BI. Surgical margins were clean without metastases.DISCUSSION: MEC of the lung is a rare tumor (0.1-0.2% of primary lung cancers) but is the most common salivary gland type tumor of the lung (SGTTLs) [1] Males are slightly more affected than females (1.5:1). Most patients are in the fourth decade of life. Symptoms vary depending on location. Central tumors (trachea, bronchi) present with dyspnea, wheezing and hemoptysis while peripheral tumors tend to present with chest pain and cough [2]. MEC tends to appear as an exophytic endobronchial tumor that is well circumscribed and smooth overlying the mucosal surface [3] Complete surgical resection is the treatment of choice. Five-year survival rate for low grade MEC is 95%. Prognosis for high grade MEC is poor and varies, with about 25% developing metastasis [2]CONCLUSIONS: MEC is an uncommon primary malignancy of the lung. While papilloma was high on the differential due to the patient's age and appearance of the lesion, negative viral cultures should increase clinical suspicion for other primary lung tumors. Furthermore, bronchoscopy should be considered in the setting of persistent lung collapse after appropriate treatment has been provided for pneumonia and an empyema to evaluate for endobronchial lesions regardless of the patient's age.Reference #1: El-Sameed YA, Al Marzooqi SH. Primary mucoepidermoid carcinoma of the lung. J Bronchology Interv Pulmonol. 2012;19 (3): 203-5.Reference #2: Kalhor N, Moran CA. Pulmonary mucoepidermoid carcinoma: diagnosis and treatment. Expert Rev Respir Med. 2018 Mar;12(3):249-255.Reference #3: Liu X, Adams AL. Mucoepidermoid carcinoma of the bronchus: a review. Arch Pathol Lab Med. 2007;131:1400–1404DISCLOSURES: No relevant relationships by Chee ChanNo relevant relationships by Yaser DawodNo relevant relationships by Vinayak JainNo relevant relationships by Syed Nazeer Mahmood SESSION TITLE: Lung Cancer Imaging Case Report Posters 2 SESSION TYPE: Case Report Posters PRESENTED ON: 10/19/2022 12:45 pm - 01:45 pm INTRODUCTION: Though rare, mucoepidermoid carcinomas (MEC) are primary salivary gland tumors that can result in airway obstruction of the lung [1,2] We present one such case in a young woman found to have persistent lobar collapse of the lung. CASE PRESENTATION: An 18-year-old female presented to the Emergency Department with progressive dyspnea and hemoptysis. She was admitted six months prior for necrotizing pneumonia with collapse of the right middle lobe (RML), right lower lobe (RLL), and concurrent empyema. Despite prolonged antibiotics and a chest tube, a computed tomography (CT) of the chest revealed persistent RML and RLL collapse. Bronchoscopy demonstrated a well circumscribed, nodular endobronchial mass in the bronchus intermedius (BI). On gross appearance, papilloma was suspected. Pathology after laser resection demonstrated inflammatory changes. All cultures were negative for bacteria and virus. She denied sexual activity. Approximately 1 week later, she presented with massive hemoptysis requiring intubation, an endobronchial blocker and embolization for stabilization. Repeat CT chest demonstrated an endobronchial lesion in the BI along with diffuse bronchiectasis throughout the RLL and RML. Once stable, repeat bronchoscopy and biopsy was conclusive for low grade mucoepidermoid carcinoma. Histopathology revealed squamous and mucinous cells positive for cytokeratin and p63, while negative for TTF-1. She has since undergone resection of her RML and RLL with lymph node dissection. Gross pathology demonstrated a 3.2 cm lesion in the BI. Surgical margins were clean without metastases. DISCUSSION: MEC of the lung is a rare tumor (0.1-0.2% of primary lung cancers) but is the most common salivary gland type tumor of the lung (SGTTLs) [1] Males are slightly more affected than females (1.5:1). Most patients are in the fourth decade of life. Symptoms vary depending on location. Central tumors (trachea, bronchi) present with dyspnea, wheezing and hemoptysis while peripheral tumors tend to present with chest pain and cough [2]. MEC tends to appear as an exophytic endobronchial tumor that is well circumscribed and smooth overlying the mucosal surface [3] Complete surgical resection is the treatment of choice. Five-year survival rate for low grade MEC is 95%. Prognosis for high grade MEC is poor and varies, with about 25% developing metastasis [2] CONCLUSIONS: MEC is an uncommon primary malignancy of the lung. While papilloma was high on the differential due to the patient's age and appearance of the lesion, negative viral cultures should increase clinical suspicion for other primary lung tumors. Furthermore, bronchoscopy should be considered in the setting of persistent lung collapse after appropriate treatment has been provided for pneumonia and an empyema to evaluate for endobronchial lesions regardless of the patient's age. Reference #1: El-Sameed YA, Al Marzooqi SH. Primary mucoepidermoid carcinoma of the lung. J Bronchology Interv Pulmonol. 2012;19 (3): 203-5. Reference #2: Kalhor N, Moran CA. Pulmonary mucoepidermoid carcinoma: diagnosis and treatment. Expert Rev Respir Med. 2018 Mar;12(3):249-255. Reference #3: Liu X, Adams AL. Mucoepidermoid carcinoma of the bronchus: a review. Arch Pathol Lab Med. 2007;131:1400–1404 DISCLOSURES: No relevant relationships by Chee Chan No relevant relationships by Yaser Dawod No relevant relationships by Vinayak Jain No relevant relationships by Syed Nazeer Mahmood