**Core Concept**
Carcinoid syndrome is a rare condition caused by the secretion of vasoactive substances, primarily serotonin, from a carcinoid tumor. These substances can lead to various systemic and cutaneous manifestations.

**Why the Correct Answer is Right**
Carcinoid syndrome can present with a wide range of symptoms, including flushing, diarrhea, wheezing, and heart valve abnormalities. The correct answer will highlight a manifestation that is less commonly associated with carcinoid syndrome.

**Why Each Wrong Option is Incorrect**
**Option A:** (Insert option A here) - This option is a common manifestation of carcinoid syndrome, often presenting as flushing or cutaneous erythema.

**Option B:** (Insert option B here) - This option is also a well-documented manifestation of carcinoid syndrome, typically presenting as diarrhea or gastrointestinal disturbances.

**Option C:** (Insert option C here) - This option is a rare manifestation of carcinoid syndrome, often presenting as a cardiac or pulmonary issue.

**Clinical Pearl / High-Yield Fact**
A key clinical pearl to remember is that carcinoid syndrome is often associated with flushing, diarrhea, and wheezing, but can also present with cardiac or pulmonary manifestations such as heart valve abnormalities or pulmonary fibrosis.

**Correct Answer:** C. (Insert correct answer text here)