**Core Concept**
The patient's presentation of progressive proptosis that worsens with bending forward, coupled with a compressible and non-tender mass without bruit or thrill, suggests a diagnosis related to the orbit and its contents. The USG finding of a "hyperintense" mass with shadowing is indicative of a specific orbital pathology.

**Why the Correct Answer is Right**
The patient's symptoms and USG findings are consistent with a diagnosis of a dermoid cyst. Dermoid cysts are congenital lesions that contain skin and subcutaneous tissue elements, which can cause proptosis and are compressible. The "hyperintense" appearance on USG is due to the presence of sebaceous material within the cyst. The absence of bruit or thrill suggests that the lesion is not highly vascularized, which is consistent with a dermoid cyst.

**Why Each Wrong Option is Incorrect**
**Option A:**
A cavernous hemangioma would typically present with a bruit on auscultation due to its high vascularity, which is not the case here.

**Option B:**
A thyroid ophthalmopathy would typically present with bilateral proptosis, lid retraction, and other systemic symptoms of thyroid disease, which are not mentioned in the scenario.

**Option C:**
A lacrimal gland tumor would typically present with a firm, non-compressible mass and may be associated with epiphora, which is not the case here.

**Clinical Pearl / High-Yield Fact**
Dermoid cysts are benign, congenital lesions that can present in various locations, including the orbit, and are often diagnosed incidentally on imaging studies.

**Correct Answer:** D. Dermoid cyst.