**Core Concept**
The patient's presentation suggests a disorder of sex development or a condition causing early puberty, possibly due to an underlying endocrine or genetic disorder. The combination of precocious puberty, bony lesions, and hyperpigmented skin lesions points towards a specific diagnosis.

**Why the Correct Answer is Right**
The patient's symptoms are consistent with McCune-Albright syndrome, a genetic disorder characterized by polyostotic fibrous dysplasia (bony lesions), café-au-lait spots (hyperpigmented skin lesions), and precocious puberty. This condition is caused by activating mutations in the Gs alpha subunit of the G protein, leading to excessive cAMP signaling in various tissues, including the ovaries, leading to premature activation of the hypothalamic-pituitary-gonadal axis.

**Why Each Wrong Option is Incorrect**
**Option A:** This option does not match the patient's presentation. Cushing's syndrome, caused by excess cortisol, typically presents with weight gain, hypertension, and striae, not precocious puberty or bony lesions.
**Option B:** This option is incorrect because neuroblastoma, a childhood cancer, typically presents with abdominal masses, bone pain, and paraneoplastic syndromes, not precocious puberty or café-au-lait spots.
**Option C:** This option is not consistent with the patient's symptoms. Sotos syndrome, a genetic disorder, presents with macrocephaly, intellectual disability, and distinctive facial features, not precocious puberty or bony lesions.

**Clinical Pearl / High-Yield Fact**
McCune-Albright syndrome is a classic example of a genetic disorder causing precocious puberty, and its diagnosis should be considered in any child presenting with early pubertal changes, especially when accompanied by bony lesions and café-au-lait spots.

**Correct Answer:** C. McCune-Albright syndrome.