X ray of skull showing multiple lesions. The diagnosis is?
**Core Concept**
The question is testing the student's ability to identify a radiological sign of a specific disease process affecting the skull. The underlying concept is the presence of multiple lesions on a skull X-ray, which can be indicative of a variety of conditions, including infections, neoplasms, or metabolic disorders.
**Why the Correct Answer is Right**
The correct answer is based on the presence of multiple lytic lesions on the skull X-ray, which is characteristic of **Multiple Myeloma**. This is a type of plasma cell dyscrasia that results in the proliferation of malignant plasma cells in the bone marrow, leading to the destruction of bone tissue and the formation of lytic lesions. The lesions are typically well-defined, punched-out, and multiple, and can be seen on X-ray as a result of the destruction of cortical bone.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it does not specify a disease process that is commonly associated with multiple lytic lesions on the skull X-ray. While certain infections, such as osteomyelitis, can cause lytic lesions, they are typically solitary and not multiple.
* **Option B:** This option is incorrect because it is not a specific disease process that is commonly associated with multiple lytic lesions on the skull X-ray. While certain metabolic disorders, such as hyperparathyroidism, can cause bone resorption and lytic lesions, they are typically not as well-defined or multiple as those seen in multiple myeloma.
* **Option C:** This option is incorrect because it is not a specific disease process that is commonly associated with multiple lytic lesions on the skull X-ray. While certain neoplasms, such as metastatic disease, can cause lytic lesions, they are typically not as well-defined or multiple as those seen in multiple myeloma.
**Clinical Pearl / High-Yield Fact**
Remember that the presence of multiple lytic lesions on a skull X-ray is highly suggestive of multiple myeloma, and a bone marrow biopsy or serum protein electrophoresis should be performed to confirm the diagnosis. Additionally, the presence of lytic lesions in multiple bones is a red flag for multiple myeloma, and further evaluation is warranted.
**Correct Answer:** C.