Primary myoepithelioma of the lungs: a case report

Background: Primary myoepithelioma of the lungs is a very rare tumor, accounting only for 0.1-0.2% of all lung tumors.  These tumors usually arise from the salivary and submucosal glands of the respiratory tracheobronchial epithelium. Generally, they are described morphologically as well-circumscribed lesions exhibiting epithelial and or myoepithelial elements in different proportions within a hyalinized to chondromyxoid stroma. Tissue sampling for histological and immunohistochemical evaluations is the gold standard for a definitive diagnosis.  It was first described by Higashiyama et al. in 1998 and in 2015, only eight actual cases were reported. To date, there are approximately 15 cases published worldwide. There is no local documented case of myoepithelioma yet, hence, this will be the first case to be recorded in the Philippines.

We report a case of primary myoepithelioma of the lung in a 67-year-old Filipino male, who is a 23.5 pack-year smoker, who presented to our institution with an 11-month history of recurrent cough and shortness of breath. Chest imaging showed a convex density 5.7 cm. in diameter at the right hilar region, not suitable for a transthoracic needle biopsy. A bronchoscopic examination with tumor resection and cryobiopsy were then performed for diagnostic evaluation. The histopathologic and differentiating immunostaining technique (consisting of pancytokeratin, TTF-1, p63, SMA, S100, synaptophysin, chromogranin, and Ki67), demonstrated a bronchial mass consistent with primary myoepithelioma.Given the rare existence of this tumor, suitable recommendations for treatment are still challenging to frame. Be that as it may, the patient is advised tumor resection.