**Question:** Lacunar cells are seen in which type of lymphoma:(1991)

**Core Concept:** Lacunar cells are a characteristic feature of a specific type of lymphoma, specifically diffuse large B-cell lymphoma (DLBCL). In DLBCL, large malignant B-cells form diffuse sheets and sheets of cells with irregular nuclei, resulting in the term "diffuse." These cells are called lacunar cells due to their arrangement within the lymphoid follicles, resembling the lacunae or cavities within them.

**Why the Correct Answer is Right:** Diffuse large B-cell lymphoma (DLBCL) is a subtype of non-Hodgkin lymphoma (NHL), where malignant B-cells grow and proliferate rapidly, leading to a high grade of malignancy. The presence of lacunar cells in DLBCL helps in distinguishing it from other types of NHL, as the arrangement of cells is unique to this specific lymphoma.

**Why Each Wrong Option is Incorrect:**

A. Non-Hodgkin lymphoma (NHL) is a group of lymphoid malignancies characterized by abnormal B-cell or T-cell proliferation. However, this option does not specify the correct subtype with lacunar cells, which is DLBCL.

B. Hodgkin lymphoma (HL) is another type of lymphoma, but it is characterized by the presence of Reed-Sternberg cells, not lacunar cells.

C. Follicular lymphoma is another type of lymphoma but it is characterized by the presence of follicular center cell proliferation, not lacunar cells.

D. T-cell lymphomas are another group of lymphomas, but they are typically characterized by the presence of T-cell proliferation, not lacunar cells.

**Clinical Pearl:**

Lymphoma is a group of malignant disorders affecting the lymphatic system, characterized by the proliferation of lymphoid cells. Understanding the specific features of different lymphoma subtypes helps in accurate diagnosis and treatment planning. In the case of DLBCL, the presence of lacunar cells is a crucial diagnostic feature that distinguishes it from other types of lymphoma, such as Hodgkin lymphoma or follicular lymphoma. This knowledge is essential for medical professionals to correctly identify and manage patients with lymphoma.