A 73-year-old male was admitted with hemoptysis for 2 months. He was diagnosed to have sputum-positive pulmonary tuberculosis 4 years back and was treated with antitubercular drugs for 6 months. Contrast-enhanced computed tomography (CT) of the thorax at that time revealed a cavitary lesion with surrounding consolidation in the right lower lobe of the lung. Contrast-enhanced CT of the chest during present admission showed a mass lesion in the lower lobe of the right lung, which was diagnosed as large cell neuroendocrine carcinoma of the lung on histopathological examination. We describe a patient who developed large cell neuroendocrine carcinoma of the lung in a posttuberculosis cavity which, to our knowledge, is the first such report.
Keywords: Large cell neuroendocrine carcinoma, lung, posttuberculosis cavity
| Introduction|| |
Pulmonary tuberculosis (PTB) and lung malignancy are common diseases in the community. The simultaneous or sequential occurrence of PTB and lung malignancy was reported previously. Chronic inflammation and pulmonary fibrosis secondary to TB can lead to genetic changes, which predispose the patient for lung malignancy. PTB can alter immune mechanisms which may also contribute to the increased incidence of lung malignancy.
| Case Report|| |
A 73-year-old male was admitted with hemoptysis for 2 months. He had streaky hemoptysis daily with a few episodes of frank hemoptysis (20 ml fresh blood). He had a loss of appetite and weight loss (10 kg in the last 2 months). He had type 2 diabetes mellitus and coronary artery disease for the past 20 years and was on regular medications. He was diagnosed to have sputum-positive PTB 4 years back and was treated with antitubercular drugs for 6 months. Contrast-enhanced computed tomography (CT) of the thorax at that time revealed a cavitary lesion with surrounding consolidation in the right lower lobe of the lung. He was a smoker for the last 40 years and had no other addictions. He denied a history of high-risk behavior and had no sick contacts. On examination, he had Grade 3 clubbing, was afebrile, and had normal blood pressure. The rest of the examination was unremarkable.
Hemoglobin was 12.7 g/dl, total leukocyte count was 8550/ml, platelet count was 290,000/μL, and erythrocyte sedimentation rate was 32 mm in 1 h. Biochemical parameters were normal. HIV, hepatitis B, and hepatitis C serology were negative. Chest X-ray showed a rounded lesion in the lower lobe of the right lung. Contrast-enhanced CT of the chest showed a mass lesion in the lower lobe of the right lung [Figure 1]a. Histopathological examination of the lesion by CT-guided biopsy showed large cell neuroendocrine carcinoma of the lung with a high proliferative index (Ki-67 – 40%) [Figure 1]b, [Figure 1]c, [Figure 1]d, [Figure 1]e, [Figure 1]f. He was transferred to the oncology department for further management. The patient had localized disease and underwent thoracoscopic radical surgery, followed by postoperative adjuvant chemotherapy (etoposide and carboplatin).
|Figure 1: Contrast-enhanced computed tomography of chest showing a mass lesion in the lower lobe of the right lung (a). Histopathological examination of the lesion showing lobular pattern, peripheral palisading, and large areas of necrosis (b) with high proliferative index (Ki-67 – 40%) (c) and positivity for CD56, synaptophysin, and chromogranin (d-f) suggestive of large cell neuroendocrine carcinoma|
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| Discussion|| |
Risk factors such as smoking, chronic obstructive pulmonary disease, and immunosuppression are common for lung cancer and PTB. PTB and lung cancer in the same patient can either occur together or back-to-back. Post-TB lung malignancy can be explained by various mechanisms. Scars following PTB cause injury to the blood vessels and lymphatics, resulting in lymphostasis and deposit carcinogens. Chronic inflammation produces reactive species by activated neutrophils and macrophages, causing genomic changes. Mutations involving the fragile histidine triad gene can predispose the patients for lung cancer following PTB. Regeneration following chronic inflammation can stimulate metaplasia and thereby cause neoplasia. The cancer risk following PTB is maximum in the first 5 years, but the risk persists even up to 20 years after PTB.
Carcinoma following PTB commonly develops in the scar tissue and involves the upper lobes usually. Studies by Vesna Cukic et al. and Cicėnas and Vencevičius showed that squamous cell carcinoma is common during PTB infection., Studies on the relationship between preexisting TB and lung cancer risk showed that only adenocarcinoma was associated with TB. It was also found that malignancy developing from scar was usually adenocarcinoma. B-cell lymphoma and small-cell carcinoma were also other histological types reported in the previous studies. Our patient had sputum-positive PTB with a cavitary lesion in the right lower lobe of the lung, which was treated following which he developed large cell neuroendocrine carcinoma of the lung in the same region after 4 years. We describe a patient who developed large cell neuroendocrine carcinoma of the lung in a post-TB cavity which, to our knowledge, is the first such report.
Declaration of patient consent
The authors certify that we have obtained the appropriate patient consent forms. In the form, the patient has given his consent for his image and other clinical information to be reported in the journal. The patient understands that his name and initials will not be published and due efforts will be made to conceal his identity, but anonymity cannot be guaranteed.
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Conflicts of interest
There are no conflicts of interest.
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Mansoor C Abdulla,
Department of General Medicine, Nizar Hospital, Valanchery - 679 338, Kerala
Source of Support: None, Conflict of Interest: None