## Core Concept
Aneurysmal bone cysts (ABCs) are benign, expansile, and lytic bone lesions that can occur in any bone but are most commonly found in the long bones and spine. They are characterized by a fluid-filled, blood-filled, or blood-filled cavity within the bone, leading to its expansion. The exact cause of ABCs is often unclear, but they can be associated with trauma, and some are thought to be related to other bone lesions.

## Why the Correct Answer is Right
The correct understanding of aneurysmal bone cysts involves recognizing their typical presentation, histological features, and management. ABCs are known for their expansile nature, often leading to cortical thinning and sometimes pathological fractures. They are usually filled with blood or fluid and lined by a fibrous membrane. The most effective treatment often involves curettage (surgical scraping out of the lesion) and sometimes additional measures like bone grafting to fill the defect.

## Why Each Wrong Option is Incorrect
- **Option A:** Without the specific details of option A, we cannot directly address its accuracy regarding aneurysmal bone cysts. However, any statement claiming that ABCs are malignant or that they exclusively occur in a specific age group or bone without exception could be considered incorrect.
- **Option B:** Similarly, without specifics, if option B suggests that ABCs are always symptomatic or always asymptomatic, this could be misleading as ABCs can present with pain or be incidentally discovered.
- **Option C:** If option C mentions a specific characteristic that is commonly associated with ABCs, such as their lytic nature on X-rays or their potential to cause bone expansion, then it would not be the incorrect statement we're looking for.
- **Option D:** This option is marked as the correct answer but without context, we assume it presents an incorrect statement about ABCs.

## Clinical Pearl / High-Yield Fact
A key point to remember about aneurysmal bone cysts is that they have a high recurrence rate after treatment, which can range from 20% to 40%, depending on the series and the specifics of the treatment approach. This makes long-term follow-up essential.

## Correct Answer: D.