A 20-year-old carpenter with a wound infection on his left thumb presents with an enlarged and tender lymph node in the axilla. A lymph node biopsy shows follicular enlargement and hyperemia. The sinuses are filled with neutrophils. Which of the following is the most likely diagnosis?
**Core Concept**
Follicular enlargement and hyperemia of lymph nodes with neutrophil infiltration, particularly in the context of a localized wound infection, points towards a diagnosis of acute bacterial lymphadenitis. This condition is characterized by the inflammatory response of the lymph node to bacterial invasion, leading to follicular enlargement and sinus histiocytosis filled with neutrophils.
**Why the Correct Answer is Right**
The presence of neutrophils in the lymph node sinuses is a hallmark of acute bacterial infection. In this case, the carpenter's wound infection on his thumb is likely the source of the bacterial invasion, leading to the inflammatory response in the axillary lymph node. The lymph node's follicles become enlarged and hyperemic due to the increased cellular activity, and the sinuses fill with neutrophils as part of the acute inflammatory response.
**Why Each Wrong Option is Incorrect**
* **Option B:** This option is incorrect because it refers to a condition characterized by granulomatous inflammation, which is typically seen in chronic infections like tuberculosis or sarcoidosis. The presence of neutrophils in the lymph node sinuses is more indicative of an acute infectious process.
* **Option C:** This option is incorrect because it refers to a condition characterized by the proliferation of germinal centers, which is typically seen in lymphoid neoplasms like follicular lymphoma. The clinical context and histological findings in this case are more consistent with an acute bacterial infection.
* **Option D:** This option is incorrect because it refers to a condition characterized by the absence of lymphoid cells in the lymph node, which is typically seen in lymphoma or other immunodeficiency states. The presence of neutrophils in the lymph node sinuses is more indicative of an acute infectious process.
**Clinical Pearl / High-Yield Fact**
It's essential to remember that the presence of neutrophils in the lymph node sinuses is a key feature of acute bacterial lymphadenitis. This can be a useful clue in differentiating acute bacterial infection from other causes of lymphadenopathy, such as chronic infections or lymphoid neoplasms.
**Correct Answer:** A. Acute bacterial lymphadenitis.