**Question:** All of the following statements regarding primary effusion lymphoma are true, except:

A. Primary effusion lymphoma (PEL) is a rare form of non-Hodgkin lymphoma characterized by the accumulation of malignant cells in body cavities such as the pleura, pericardium, or peritoneum.
B. PEL is more common in patients with human immunodeficiency virus (HIV) infection or other immunodeficiencies.
C. PEL typically presents with symptoms related to the affected cavity, such as chest pain, dyspnea, or abdominal distension.
D. PEL does not respond well to conventional chemotherapy and radiotherapy.

**Correct Answer:** **Option C: Primary effusion lymphoma typically presents with symptoms related to the affected cavity, such as chest pain, dyspnea, or abdominal distension.**

**Core Concept:** Primary effusion lymphoma (PEL) is a rare form of non-Hodgkin lymphoma characterized by the accumulation of malignant cells in body cavities like pleura, pericardium, or peritoneum. These cells can cause symptoms due to pressure effects or obstruction of adjacent structures.

**Why the Correct Answer is Right:** In contrast to Option C, PEL is not just about presenting symptoms related to the affected cavity. In fact, the primary tumor growth in PEL occurs in the body cavities, leading to effusion formation and subsequent symptoms. However, the symptoms are a result of the pressure effects and obstruction of adjacent structures caused by the malignant cells.

**Why Each Wrong Option is Incorrect:**

**Option A:** Primary effusion lymphoma (PEL) is indeed a rare lymphoma, but it is not specifically characterized by the accumulation of malignant cells in body cavities. The correct definition should be: PEL involves the accumulation of malignant cells in body cavities and is a rare form of non-Hodgkin lymphoma.

**Option B:** Although PEL is more common in patients with HIV infection or other immunodeficiencies, the statement that PEL does not respond well to conventional chemotherapy and radiotherapy is incorrect. PEL can be treated effectively with chemotherapy, especially when combined with liposomal doxorubicin, bleomycin, vinblastine, and prednisolone (ABVP) regimen.

**Option D:** As mentioned earlier, PEL is a type of non-Hodgkin lymphoma characterized by malignant cells accumulating in body cavities, specifically pleural, pericardial, or peritoneal. However, the statement that PEL does not respond well to conventional chemotherapy and radiotherapy is incorrect. With the use of ABVP regimen, PEL can be treated effectively and efficiently.