Glomus tumour arises from: September 2004
**Core Concept**
Glomus tumours are a rare type of neoplasm that arises from the glomus body, a specialized structure in the dermis responsible for thermoregulation and blood pressure regulation. They are often associated with the skin, particularly on the fingers or toes, but can also occur in the gastrointestinal tract or other locations.
**Why the Correct Answer is Right**
Glomus tumours originate from the modified smooth muscle cells of the glomus body, which is composed of specialized cells called glomus cells. These cells are surrounded by a network of capillaries and are involved in the regulation of blood flow and pressure. The growth of glomus tumours is characterized by an overproduction of these specialized cells, leading to a benign or malignant neoplasm.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as glomus tumours do not arise from the sweat glands, which are a different type of skin appendage.
**Option B:** This option is incorrect as glomus tumours do not arise from the hair follicles, which are also a different type of skin appendage.
**Option C:** This option is incorrect as glomus tumours do not arise from the nerve sheaths, which are associated with the peripheral nervous system.
**Clinical Pearl / High-Yield Fact**
Glomus tumours are known for their characteristic symptoms, including pain and tenderness localized to the affected area, often accompanied by a bluish discoloration due to the presence of dilated capillaries.
**Correct Answer: C. Glomus tumours arise from the modified smooth muscle cells of the glomus body.**