A Rare Lung Malignancy in a Case of Systemic Sclerosis

Systemic sclerosis (SSc) is one of the chronic autoimmune diseases characterized by the infiltration of excess collagen in various organs, especially the skin. It is found to be associated with a higher prevalence of internal malignancies, particularly lung carcinoma. Herein, we report a case of adenosquamous carcinoma confining within the lung in a patient who had long-standing SSc. She was a 55-year-old female patient presenting with progressive dry cough and breathlessness for six months. She had been a known case of diffuse cutaneous SSc for over a decade, based on 2013 American College of Rheumatology (ACR) criteria. The diagnosis is made based on her findings of bilateral thickening of the fingers on both hands, extending up to the metacarpophalangeal joints. Furthermore, she had telangiectasia at the upper chest wall and neck, multiple pitting scars at the toes, Raynaud's esophageal dilatation, and interstitial lung disease (ILD). She had been treated on Mycophenolate Mofetil 500 mg twice daily and low-dose prednisolone 5 mg once daily for 10 years. The patient's high-resolution computed tomography (HRCT) of the chest revealed a subpleural nodule in the posterior basal segment of the left lower lobe with areas of reticular opacities and interlobular septal thickening on bilateral lung fields six months earlier. The current computed tomography of the lung revealed a new 2.6 x 2.5 cm ill-defined lesion with irregular margins at the left lower lobe. A CT-guided biopsy was done for the lesion, which revealed adenosquamous carcinoma. Immunohistochemistry was consistent with a diagnosis of primary pulmonary adenosquamous carcinoma. The patient did not accept any further investigations and/or treatment. Herein, we present a rare lung malignancy, adenosquamous carcinoma of the lung with an underlying long-term diffuse cutaneous SSc in a nonsmoking female, which highlights the importance of lung cancer screening in individuals with SSc complicated with ILD and supports the fact that there is an increased prevalence of lung cancer among SSc-ILD patients than that of the regular population.