**Core Concept**
Neuroblastoma is a type of pediatric cancer that arises from the sympathetic nervous system, primarily affecting children under the age of 5. It can present with a wide range of clinical manifestations, including abdominal masses, bone metastases, and paraneoplastic syndromes.

**Why the Correct Answer is Right**
Splenomegaly is not a typical presentation of neuroblastoma. Neuroblastomas often present as abdominal masses, and in cases where they do involve the spleen, it's usually due to metastatic spread or contiguous spread from an adjacent tumor site. However, significant splenomegaly is not a characteristic feature of neuroblastoma, unlike other paraneoplastic syndromes such as diarrhea, which can be seen due to vasoactive intestinal peptide (VIP) production.

**Why Each Wrong Option is Incorrect**
**Option A:** Diarrhea can be seen in neuroblastoma due to the production of vasoactive intestinal peptide (VIP), leading to a VIPoma-like syndrome.
**Option B:** Proptosis can occur in neuroblastoma due to orbital metastases, which can cause exophthalmos.
**Option D:** Bone involvement is a common feature of neuroblastoma, with metastases often seen in the skull, ribs, and long bones.

**Clinical Pearl / High-Yield Fact**
Neuroblastoma is the most common extracranial solid tumor in children, and its presentation can be highly variable, making it essential to consider this diagnosis in any child presenting with an abdominal mass or symptoms suggestive of neuroblastoma.

**✓ Correct Answer: C. Splenomegaly**