INTRODUCTION: Mucoepidermoid carcinomas are rare, and account for about 0.1-0.2%lung tumors.Lesions may result in bronchial obstruction and atelectasis, and patients typically present with cough, chest pain, hemoptysis, wheezing, or a post-obstructive PNA.We present an 18-year-old female who was seen in our pediatric pulmonology clinic and found to have a low grade mucoepidermoid carcinoma of the left mainstem bronchus.PRESENTATION: An 18-year-old non-smoking female was referred for expiratory wheezing of 7 months duration, without cough.Symptoms were not progressive, and the patient's only other complaint was occasional mild SOA that would quickly resolve with rest.She denied illness or other systemic symptoms, and there was no prior personal history of lung disease.Prior to our assessment, she had a normal CXR, had completed two rounds of systemic steroids and one round of antibiotics, and tried albuterol without improvement.PFTs revealed severe obstruction.A chest CT was performed and showed a 10x8x10 mm enhancing endobronchial lesion along the left mainstem bronchus with significant airway luminal compromise.She underwent combined rigid and flexible bronchoscopies and had complete resection of a friable mass, which was ultimately diagnosed as a low grade mucoepidermoid carcinoma.Wheezing resolved after resection, and both whole body PET scan and combined surveillance bronchoscopies after resection failed to show residual or metastatic disease.DISCUSSION: Mucoepidermoid carcinomas are common lesions originating in the parotid or submandibular salivary glands, but an uncommon pulmonary finding, accounting for less than 0.3% of lung tumors.It is thought that about 20% of cases present before 20 years of age, but data is exceptionally limited in pediatrics.When originating in the lung, they are believed to develop from the minor salivary glands in the tracheobronchial tree, and more commonly are found in the central airways and proximal bronchi.With categorizations of low or high grade, high grade lesions have a similar prognosis as non-small cell lung cancer.However, low-grade lesions have an excellent five-year prognosis in adults with 95% survival rate after surgical resection.They can be confused with carcinoid tumor on bronchoscopy, and clinical and radiographic findings are non-specific, making diagnosis dependent on biopsy and pathology.There is also an association with MAML2 gene rearrangement and mucoepidermoid carcinoma, of which our patient was positive for on genetic testing.CONCLUSION: This case adds to the sparse existing literature of primary pulmonary mucoepidermoid carcinomas in pediatric patients.

Rationale: Knowledge and awareness of dietary guidelines has been linked to having a healthier diet and better diet quality.1-4 The aim of this study is to investigate Saudi Mothers knowledge of current dietary guidelines regarding food groups and portion sizes and to investigate its relation to the sociodemographic factors.