‘Row of tombstones’ appearance is seen in :
**Core Concept**
The 'row of tombstones' appearance is a characteristic histopathological finding associated with a specific condition. It refers to a particular arrangement of nuclei or cells that resembles a row of tombstones, typically seen in certain types of cellular pathology.
**Why the Correct Answer is Right**
The 'row of tombstones' appearance is classically seen in **Histiocytic necrotizing lymphadenitis**, also known as **Kikuchi disease**. This condition is characterized by a lymph node biopsy showing a distinctive pattern of histiocytic infiltration and necrosis, with a row of necrotic histiocytes resembling tombstones. The pathogenesis of Kikuchi disease is not fully understood, but it is thought to involve an abnormal immune response, leading to the accumulation of histiocytes and necrosis in the lymph nodes.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because the 'row of tombstones' appearance is not typically associated with **Sarcoidosis**, which is a granulomatous disease characterized by the presence of non-caseating granulomas.
* **Option B:** This option is incorrect because **Castleman disease** is a lymphoproliferative disorder that can present with a variety of histopathological features, but the 'row of tombstones' appearance is not a characteristic finding.
* **Option C:** This option is incorrect because **Kaposi's sarcoma** is a type of malignant neoplasm that can present with a variety of histopathological features, but the 'row of tombstones' appearance is not a characteristic finding.
**Clinical Pearl / High-Yield Fact**
The 'row of tombstones' appearance is a distinctive histopathological feature that can help diagnose Kikuchi disease. It is essential to recognize this finding in a lymph node biopsy to avoid misdiagnosing the condition as another type of lymphadenitis or lymphoma.
**Correct Answer: D. Kikuchi disease**