**Question:** A 48-year-old woman is admitted with a history of weakness for two months. On examination, cervical lymph nodes are enlarged, and the spleen is palpable 2 cm below the costal margin. Her hemoglobin is 10.5 g/dL, platelet count is 2.7 x 10^9/L, and total leukocyte count is 40 x 10^9/L, which includes 80% mature lymphoid cells with coarse clumped chromatin. Bone marrow revealed nodular lymphoid infiltrate. The peripheral blood lymphoid cells were positive for CD19, CD5, CD20, CD23, and were negative for CD79B and FMC-7. The histopathological examination of the lymph node in this patient will most likely exhibit effacement of lymph node architecture by:

A. Lymphoid hyperplasia
B. Lymphoid malignancy
C. Lymphoid fibrosis
D. Lymphoid hyperplasia and fibrosis

**Correct Answer:**

**Core Concept:**

In this scenario, the patient presents with clinical and laboratory findings suggestive of a lymphoproliferative disorder, characterized by the presence of mature lymphoid cells with coarse clumped chromatin and positive staining for CD19, CD5, CD20, CD23, and negative staining for CD79B and FMC-7. The findings suggest a B-cell lymphoproliferative disorder, likely B-cell non-Hodgkin lymphoma (NHL).

**Reasoning:**

The histopathology examination of the lymph node in this patient will most likely exhibit effacement of lymph node architecture due to the infiltration of the affected lymph node by malignant B-cells. In this context, lymphoid hyperplasia refers to the excessive proliferation of lymphocytes, while fibrosis refers to the excessive deposition of collagen fibres in the lymph node, leading to tissue remodeling and distortion of architecture.

Given the clinical presentation and laboratory findings, the correct answer is:

**Correct Answer:** B. Lymphoid malignancy

**Explanation:**

The correct answer is B, "lymphoid malignancy," due to the clinical presentation and laboratory findings that indicate the presence of a lymphoproliferative disorder. The patient's symptoms, lymphadenopathy, and abnormal lymphoid cells with coarse clumped chromatin and positive staining for CD19, CD5, CD20, CD23, and negative staining for CD79B and FMC-7, suggest a B-cell non-Hodgkin lymphoma (B-cell NHL).

**Clinical Pearls:**

1. In B-cell NHL, the lymph nodes are typically involved in the early stages, leading to lymphadenopathy (enlarged lymph nodes).
2. The distinctive immunohistochemical findings of CD19, CD5, CD20, CD23, and negative staining for CD79B and FMC-7 are indicative of B-cell lymphoma.
3. The correct answer is B as the histopathology examination is expected to show effacement of lymph node architecture due to the infiltration