I think there's been a mistake in the subject/topic. This question is actually about Rheumatology, not Gynaecology & Obstetrics.

**Core Concept**
The question describes a classic radiographic finding associated with gout, a form of inflammatory arthritis characterized by the deposition of monosodium urate crystals in joints and surrounding tissues. The presentation of acute onset pain and swelling of the great toe, known as podagra, is a hallmark of gout.

**Why the Correct Answer is Right**
The description of a "punched out lytic lesion" on the phalanx with sclerotic margins and overhanging bony edges is characteristic of a gouty tophus. This is due to the deposition of urate crystals in the joint, leading to inflammation and subsequent bone erosion. The sclerotic margins and overhanging bony edges are a result of the body's attempt to repair the damaged bone. The presence of monosodium urate crystals in the joint fluid, as confirmed by a polarized light microscope, would further support the diagnosis of gout.

**Why Each Wrong Option is Incorrect**
**Option B:** Rheumatoid arthritis typically presents with symmetrical polyarthritis and does not characteristically cause punched out lytic lesions on X-ray.
**Option C:** Psoriatic arthritis can cause joint damage and new bone formation, but it does not typically present with the classic radiographic findings of gout.
**Option D:** Reiter's syndrome (now known as reactive arthritis) is a type of arthritis that occurs in response to an infection, but it does not typically cause the specific radiographic findings described in the question.

**Clinical Pearl / High-Yield Fact**
Gout is often referred to as the "disease of kings" due to its historical association with a rich diet and excessive alcohol consumption. However, it is now recognized as a common and treatable condition that affects millions of people worldwide.

**✓ Correct Answer: A. Gout**