**Core Concept**
Peau d'orange, also known as orange peel skin, is a clinical sign characterized by a dimpled or skin texture resembling an orange peel. It occurs due to lymphedema and subsequent fibrosis, leading to the obstruction of lymphatic vessels.

**Why the Correct Answer is Right**
The peau d'orange appearance is a result of lymphatic obstruction, which leads to the accumulation of fluid and proteins in the dermal interstitium. This causes the skin to become thickened and fibrotic, resulting in the characteristic peau d'orange appearance. The lymphatic obstruction can be due to various factors such as breast cancer, especially inflammatory breast cancer, or other conditions like lymphedema.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as edema is a general term that refers to the accumulation of fluid in tissues, but it does not specifically describe the peau d'orange appearance.
**Option B:** This option is incorrect as inflammation is a broader term that refers to the body's response to injury or infection, but it does not specifically describe the peau d'orange appearance.
**Option C:** This option is incorrect as fibrosis is a term that refers to the formation of excess fibrous connective tissue, but it does not specifically describe the peau d'orange appearance.

**Clinical Pearl / High-Yield Fact**
Peau d'orange is a clinical sign that requires prompt investigation, especially in the context of breast cancer, as it can be associated with a poor prognosis. A high index of suspicion and thorough clinical examination are essential in identifying this sign.

**Correct Answer: D. Lymphatic obstruction**