Lung squamous carcinoma with two paraneoplastic syndromes: dermatomyositis and Lambert–Eaton myasthenic syndrome

Background and Aim Paraneoplastic syndrome is a disease or symptom that is the consequence of cancer in the body but, unlike mass effect, is not due to the local presence of cancer cells. An overlap of two paraneoplastic syndromes secondary to lung cancer in a patient is very rare. In order to improve the diagnosis of two paraneoplastic syndromes secondary to lung cancer, we reported an overlap of two paraneoplastic syndromes secondary to lung squamous carcinoma in a patient. Methods We reported a case of a 60-year-old male smoker who presented multiple erythematous lesions for 6 months with progressive proximal muscular weakness, and developed to dysphonia in 2 months. His chest computed tomography showed a spiculate pulmonary nodule near the hilar in the right upper lobe and mediastinal lymph nodes enlargement. Lung biopsy showed squamous cell carcinoma. The patient's blood test revealed elevated creatine kinase levels. Electromyography results were consistent with moderate myopathy accompanied with a pattern suggestive of Lambert–Eaton myasthenic syndrome. Results So we made the diagnosis of an overlap of two paraneoplastic syndromes (dermatomyositis and Lambert–Eaton myasthenic syndrome) secondary to lung squamous carcinoma. Conclusion Recognition of paraneoplastic syndrome is crucial for early diagnosis of lung cancer because up to 80% of patients may present paraneoplastic syndromes before any other direct indication of malignancy. Early diagnosis and treatment of paraneoplastic syndrome is also important because delayed diagnosis may result in rapid disease progression and irreversible neurological damage.