**Question:** Bulging fissures in lungs is seen in –

A. Pulmonary edema
B. Pneumonia
C. Pleural effusion
D. Lung cancer

**Core Concept:** The fissures in the lungs are the visible lines that demarcate the lobes and segments of the lungs. These fissures are formed by the interlobar and intralobar pulmonary ligaments. When there is an abnormal accumulation of fluid (edema) or air (pneumonia) or excessively increased pressure (pleural effusion, lung tumors), the fissures may become visible, causing bulging.

**Why the Correct Answer is Right:**

Correct Answer: **D. Lung cancer**

In lung cancer, the affected lung tissue expands due to the abnormal growth of cells, leading to the distortion of the normal lung architecture. As a result, the fissures may become visible, causing bulging. This is not the case for options A, B, and C, as they typically cause either fluid accumulation (edema) or air accumulation (pneumonia), which would compress the fissures, making them less likely to bulge. Pleural effusions cause fluid accumulation between the pleural surfaces, reducing the visibility of fissures. Lung tumors cause compression of the affected lung and pleural surfaces, reducing the visibility of fissures.

**Why Each Wrong Option is Incorrect:**

A. Pulmonary edema is a condition where excess fluid accumulates in the alveoli, leading to reduced gas exchange and hypoxia. It does not result in visible bulging of the fissures due to the compression of the affected lung and pleural surfaces.

B. Pneumonia is an infection-induced inflammation of lung tissue, which causes infiltration of the affected area, not bulging of fissures.

C. Pleural effusions are collections of fluid between the pleural surfaces, causing compression of the affected lung and pleural surfaces. Bulging of fissures is less likely in pleural effusions.

**Clinical Pearl:**

In clinical practice, recognizing the presence of bulging fissures can be a helpful clue for diagnosing certain conditions, particularly in imaging studies like X-rays and CT scans. It is essential to have a good understanding of lung anatomy and the different pathological conditions that can lead to visible fissures. Remember, the fissures are not visible in conditions like pneumonia or pleural effusions, and their presence should raise suspicion for lung tumors or pulmonary edema.