Mau-Ern Poh

Mycobacterium Brisbanense Species Nova Isolated From a Patient With Chronic Cavitary Lung Infection

We describe the first case, to our knowledge, of Mycobacterium brisbanense species nova with the type strain W6743T (=ATCC 49938T=DSM 44680T) isolated from the lungs of a man with a 6-month history of productive cough and intermittent fever presenting with acute hypoglycemia. A CT scan of the thorax revealed multiple small nodules and consolidation over both lungs with cavitation. Sputum culture repeatedly grew M brisbanense species nova, a novel species never before isolated in Malaysia. The case met the American Thoracic Society criteria for the diagnosis of nontuberculous mycobacterial infection. There was dramatic clinical and radiologic response to treatment with an empirical combination of rifampicin, ethambutol, and levofloxacin and subsequently clarithromycin and levofloxacin once sensitivity was known. This report is the first, to our knowledge, of the pathogen isolated in a patient with chronic cavitary lung infection since it was first identified from an antral sinus in Brisbane, Queensland, Australia, and the first time it is isolated from a human subject in Malaysia.

Endobronchial metastasis from resected renal cell carcinoma causing total lung collapse

We report a man presenting with dyspnea, cough, and hemoptysis due to left lung collapse from an endobronchial tumor obstructing the left main bronchus. Endobronchial biopsy of the tumor showed renal cell carcinoma, identical to a previous specimen of renal cell carcinoma removed by a radical left nephrectomy five years ago. The endobronchial tumor was removed by snare diathermy through a flexible bronchoscope, following which his symptoms resolved and the left lung re‐expanded. Endobronchial metastasis from renal cell carcinoma is rare and can mimic obstruction from other endobronchial etiologies, such as bronchogenic carcinoma. Total lung collapse as a result is even more uncommon, although atelectasis is well described. Endobronchial techniques, such as snare diathermy, can relieve obstruction, providing symptom palliation even in advanced disease.

Advanced right lung adenocarcinoma with ipsilateral breast metastasis

Breast metastases from non‐small cell lung carcinoma are rarely reported. We report a case of a female patient with primary adenocarcinoma of the lower lobe of her right lung presenting with a massive right‐sided malignant pleural effusion. The tumor harbored an epidermal growth factor receptor insertion mutation in exon 20 but was anaplastic lymphoma kinase translocation negative. She did not respond to treatment with erlotinib. First‐ and second‐line cytotoxic chemotherapy resulted in stable disease as the best responses. She developed right breast metastasis 20 months after her initial presentation. The rarity of the condition and the likely mechanism of the breast metastasis are discussed.

Epithelial-to-mesenchymal transition (EMT) causing acquired resistance to afatinib in a patient with epidermal growth factor receptor ( EGFR )-mutant lung adenocarcinoma

We report the first case of epithelial-to-mesenchymal transition (EMT) as the cause of acquired resistance to the second-generation EGFR-tyrosine kinase inhibitor (TKI), afatinib in a patient with advanced non-small cell lung cancer (NSCLC) harboring a sensitizing EGFR mutation. Patients with EGFR-mutant NSCLC inevitably develop acquired resistance while on EGFR-TKI treatment. EMT which renders cancer cells more invasive and migratory is one of the mechanisms of acquired resistance to EGFR-TKIs and correlates with a poor prognosis. Possible therapeutic strategies in patients with EMT include blocking M2 muscarinic receptor signalling, targeting EMT with histone deacetylase inhibitors such as entinostat and MEK-inhibitors such as selumetinib, inhibition of microRNAs, immunotherapy and inhibiting fibroblast growth factor receptor-1.

Bilateral pulmonary sequestrations mimicking advanced lung malignancy

Bilateral pulmonary sequestrations are extremely rare and uncommonly diagnosed during adulthood. It can present with severe symptoms such as hemoptysis. It can also be misdiagnosed as a primary lung malignancy.