P3C249: Foreign Body Aspiration or Mass? Initial Diagnosis of a Low-grade Pulmonary Mucoepidermoid Carcinoma in an Adolescent with Recurrent Pneumonia

Introduction: Recurrent pneumonia in children frequently triggers referral to Pediatric Pulmonology. We present the case of a 17-year-old male referred to Pediatric Pulmonology for recurrent pneumonia. A mass found during bronchoscopy was thought to be a retained foreign body, but was instead a primary pulmonary low-grade mucoepidermoid carcinoma (MEC). Below, we report this case and discuss the rarity of and challenges with diagnosing these Primary Tracheobronchial Tumors (PTT).

Case Description: A 17-year-old male with no past medical history presented to his pediatrician with cough, congestion, and fever. Chest radiograph showed a left upper lobe (LUL) pneumonia (Figure 1). He was treated successfully with oral antibiotics. Days later, the cough returned. Over the next four months, he had two further episodes of LUL pneumonia. He was evaluated with a computed tomography (CT) scan, and two further radiographs. He was treated with another three courses of IV and oral antibiotics. He was then referred to Pediatric Pulmonology.

During Pulmonology consultation, he recounted aspirating a sunflower seed shortly before symptom onset. Examination at the visit was unremarkable. Spirometry showed a bronchodilator responsive obstructive pattern in his small airways. The patient was scheduled for flexible bronchoscopy.

During bronchoscopy, a small mass was seen obstructing the lingual bronchus (Figure 2). Thought to be granulomatous tissue around the aspirated sunflower seed, it was removed and sent for pathology.

Pathology revealed a low-grade MEC. At a follow up visit with pulmonology, his spirometry showed marked improvement in airflow and lung function. Repeat CT scan showed the patient had developed bronchiectasis at the site. The patient was referred to oncology and is awaiting definitive management.

Discussion: Our case highlights the challenges in diagnosing uncommon malignancies in children. MEC commonly involves the salivary glands, but is rarely seen in the bronchopulmonary tree. Primary pulmonary malignancies are rare in children, with MEC being the 2nd most common type.

Pulmonary MEC often presents with non-specific signs and symptoms including cough, pneumonia, fever, atelectasis, and dyspnea. The frequency of these vague symptoms in children makes diagnosis difficult. Multiple case reports describe how patients with MEC initially receive other diagnoses, have multiple radiographic tests, and experience an average of six months of symptoms before diagnosis. Yet, patients with low grade tumors still have excellent prognoses with surgical resection.

Conclusion: MEC is a rare and diagnostically challenging PTT seen in children and adolescents. As seen in the index case, diagnosis of this type of tumor can be challenging and requires direct tissue sampling. This case also highlights the importance of sending tissue samples for pathology. Pediatricians and pediatric medical providers should consider MEC and other PTTs on their differential when a patient presents with recurrent pneumonia (especially in the same location), cough, and fever.