**Core Concept**
Lytic lesions in the skull are characterized by bone destruction, often resulting from pathological processes such as tumors, infections, or metabolic disorders. These lesions can be caused by various factors, including osteoclast activation, bone resorption, and decreased bone formation.

**Why the Correct Answer is Right**
Lytic lesions in the skull are commonly associated with conditions like multiple myeloma, metastatic bone disease (e.g., breast or lung cancer), and certain infections (e.g., osteomyelitis). These conditions often lead to an imbalance in bone remodeling, favoring resorption over formation. In multiple myeloma, for instance, the proliferation of malignant plasma cells can lead to the production of osteoclast-activating factors, resulting in lytic bone lesions.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because lytic lesions are not typically seen in Paget's disease, which is characterized by a mix of bone resorption and formation, leading to a "cotton wool" appearance on radiographs.
**Option B:** This option is incorrect because fibrous dysplasia can cause lytic lesions, although they are often more sclerotic and contain a "ground-glass" appearance.
**Option C:** This option is incorrect because osteoblastoma is a benign bone tumor that typically causes a well-defined, expansile lytic lesion, but it is not one of the classic causes of lytic skull lesions.
**Option D:** This option is incorrect because fibrous dysplasia can cause lytic lesions, although they are often more sclerotic and contain a "ground-glass" appearance.

**Clinical Pearl / High-Yield Fact**
When evaluating lytic lesions in the skull, it's essential to consider the patient's clinical context, including their age, sex, and medical history. A thorough radiographic and laboratory evaluation can help distinguish between various underlying causes.

**Correct Answer:** D