**Core Concept**
Peutz Jeghers syndrome (PJS) is a rare genetic disorder characterized by the development of benign hamartomatous polyps in the gastrointestinal tract and an increased risk of various cancers. The syndrome is caused by mutations in the STK11 gene, which encodes a tumor suppressor protein involved in cell cycle regulation.

**Why the Correct Answer is Right**
Radiotherapy is not the treatment of choice for Peutz Jeghers syndrome. The primary treatment for PJS involves surgical removal of polyps to prevent complications such as intestinal obstruction or bleeding. In some cases, prophylactic surgery may be considered to remove the small intestine, but radiotherapy is not a standard treatment approach.

**Why Each Wrong Option is Incorrect**
**Option A:** Pigmentation of lips & oral mucosa is a hallmark of Peutz Jeghers syndrome, characterized by the presence of melanin deposits in the skin and mucous membranes, particularly around the mouth, lips, and digits. This is a true feature of PJS.
**Option B:** Polyposis of the jejunum is a common manifestation of Peutz Jeghers syndrome, with polyps often found in the small intestine, including the jejunum. This is a true feature of PJS.
**Option D:** May turn malignant is a true statement, as individuals with Peutz Jeghers syndrome have an increased risk of developing various cancers, including gastrointestinal cancers and breast cancer, due to the loss of tumor suppressor function.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that Peutz Jeghers syndrome is a hereditary disorder, and genetic testing can be used to identify mutations in the STK11 gene. This can help with early diagnosis and management of the condition.

**✓ Correct Answer: C. Radiotherapy is the treatment of choice**