In Tzank smear multinucleated cells are seen in:
**Core Concept**
The Tzank smear is a diagnostic tool used to identify viral infections, particularly herpes simplex virus (HSV) and varicella-zoster virus (VZV), by examining the morphology of cells from a skin lesion. This test is based on the principle that viral infections can cause cellular changes, such as multinucleation, which can be visualized under a microscope.
**Why the Correct Answer is Right**
In the context of a Tzank smear, multinucleated cells are characteristic of viral infections caused by HSV and VZV. These cells undergo a process called syncytial formation, where multiple nuclei are present within a single cell membrane. This phenomenon is a result of the viral infection causing the fusion of adjacent cells, leading to the formation of multinucleated giant cells. The presence of multinucleated cells in a Tzank smear is a key diagnostic feature of these viral infections.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not relevant to the Tzank smear or the diagnostic features of HSV and VZV infections.
* **Option B:** While HSV and VZV infections can cause cellular changes, they are not the only viral infections that can be diagnosed using a Tzank smear. Other viral infections, such as coxsackievirus and echovirus, can also cause similar cellular changes.
* **Option C:** This option is not relevant to the Tzank smear or the diagnostic features of HSV and VZV infections.
**Clinical Pearl / High-Yield Fact**
A Tzank smear is a useful diagnostic tool for identifying viral infections, particularly HSV and VZV, in patients with skin lesions. However, a definitive diagnosis can only be made by confirming the presence of viral DNA or antigens using molecular or serological tests.
**Correct Answer: B.**