**Question:** True about dermoid cyst of ovary:

A. It is a benign tumor
B. It is a malignant tumor
C. It contains hair and sebaceous glands
D. It is a cystic structure

**Core Concept:**
A dermoid cyst, also known as a teratoma, is a benign (non-cancerous) tumor composed of different types of tissues that develop during embryonic life. These tissues can include structures like hair, teeth, skin, and even bones and cartilage. Dermoid cysts are classified into mature (non-dangerous) and immature (potentially dangerous) types, based on the presence of potentially cancerous cells.

**Why the Correct Answer is Right:**
A dermoid cyst is indeed a benign tumor, which means it is non-cancerous and does not have the potential to spread to other parts of the body. This is because it develops from cells that normally form the outer layer of an embryo, known as the ectoderm, endoderm, and mesoderm.

**Why Each Wrong Option is Incorrect:**
B. A dermoid cyst is not classified as a malignant tumor, as it is non-cancerous and has a low potential for spreading to other parts of the body.
C. Although dermoid cysts may contain hair and sebaceous glands, they are not solely composed of these structures. Instead, they are composed of different tissues from all three embryonic layers (ectoderm, endoderm, and mesoderm).
D. A dermoid cyst is indeed a cystic structure, but it is not a malignant tumor.

**Clinical Pearl:**
Dermoid cysts are relatively rare, accounting for around 10% of ovarian tumors. They may present as a painless mass in the abdomen or pelvis, often detected during routine gynecological examination or imaging studies. Treatment typically involves surgical removal, as they can rupture and cause severe infections (empyema) due to the presence of bacteria, viruses, or other foreign substances. Ruptured dermoid cysts can lead to pyosalpinx (infection of the fallopian tube) or meningitis (infection of the cerebrospinal fluid-filled spaces within the brain).

**Why Each Wrong Option is Incorrect:**
A. While dermoid cysts can rupture and cause infections, they are not malignant tumors, so option A is incorrect.
B. Dermoid cysts are not considered malignant tumors, making option B irrelevant in this context.
C. Although dermoid cysts can rupture and cause infections, they are not solely composed of hair and sebaceous glands, making option C incorrect.
D. Dermoid cysts are not malignant tumors, making option D irrelevant in this context.

**Why the Correct Answer is Right:**
A dermoid cyst is a benign (non-cancerous) neoplasm derived from all three embryonic layers (ectoderm, endoderm, and mesoderm). They are also known as teratomas because they contain multiple tissues of varying types, including hair, teeth, nails,