The most common ovarian tumor in young, reproductive-age women is the cystic teratoma, or dermoid, which originates from a germ cell and contains elements from all three germ cell layers. These tumors may be benign or malignant (1% to 2% malignant, usually in women older than 40 years). They account for 20% to 25% of all ovarian tumors and one-third of all benign tumors. A dermoid cyst may be microscopic in size or may reach proportions up to 40 cm. Bilateral involvement occurs in 25% of cases. The tumors are usually round or oval, doughy and rather heavy, with a smooth, opaque, gray-white, or yellow surface. Their lardaceous contents tend to harden when chilled. The open specimen reveals fatty, sebaceous material, strands of long hair and an intracystic plug, covered by scalp-like skin. The tufts of hair originate mostly in this skin-lined area. The color of the hair bears no relation to that of the host. The remainder of the cyst lining appears smooth and glistening or rough and granular. Cartilage, bone, and teeth are found in two-thirds of the cases.
Histologically, almost any well-differentiated tissue of ectodermal, mesodermal, or endodermal origin may be found. The skin and its appendages predominate. Section through the dermoid plug, which corresponds to the embryonic area, may reveal the presence of strati- ﬁed squamous epithelium, sebaceous glands, sweat glands, and hair follicles. Mesodermal elements, occasionally found, include plaques of cartilage, tracheal, thyroid, and adipose tissue. Development of speciﬁc tissues may give rise to a struma ovarii (functional thyroid tissue), pseudomucinous cyst, ﬁbroma, chondroﬁbroma, or osteoﬁbroma. Portions of the cyst wall, other than the dermoid plug, may be lined by ﬂattened or cuboidal epithelium, or granulation tissue containing phagocytic, pseudoxanthoma cells and foreign-body giant cells.
Clinically, dermoid cysts may be asymptomatic or associated with lower abdominal pain, abdominal enlargement, or pressure symptoms. A position anterior to the uterus is common. Palpation of a doughy, cystic, heavy ovarian tumor is suggestive. X-ray demonstration of teeth is pathognomonic. Because dermoids are almost always pedunculated, torsion is common. Leakage or rupture gives rise to an irritative, chemical peritonitis and dense adhesions; adhesions around dermoids are common. Therapy includes cystectomy or oophorectomy. Because of the frequent bilateral involvement, the opposite ovary should be carefully inspected. It must be kept in mind that dermoids may be multiple in a single ovary.
The solid or embryonal teratomas are malignant tumors composed of poorly differentiated, highly proliferative elements derived from all three germ layers. They are, fortunately, rare, constituting less than 1% of all dermoid growths. The neoplasms are usually unilateral, round or oval, smooth or lobulated. Most often they are small or moderate in size but may reach large proportions. Though generally solid and ﬁrm, necrosis and cystic degeneration may impart a softer consis- tency. The capsule may be intact or perforated by the highly malignant, proliferating tissue, with adherence to surrounding structures. On section, a variegated consistency and coloration are apparent, depending upon the predominance of different tissues and the degree of degeneration, hemorrhage, and cavitation. Microscopically, well-differentiated areas may exist side by side with young embryonal, undifferentiated portions as well as unidentiﬁable sarcomatous or carcinomatous tissues. Mesodermal structures are frequently more abundant and include connective tissue, cartilage, bone, lymphoid tissue, and smooth or striated muscle. Ectoderm may be represented by nervous system tissue. Skin and appendages are rare.
The diagnosis is usually not made until laparotomy or laparoscopy is performed. The presence of a solid, heavy, rapidly growing neoplasm in a young individual is suggestive. Perforation of the capsule, local extension, dissemination throughout the abdomen, retroperitoneal lymph node involvement, and distant metastases may occur. Metastatic extension may involve only a sarcomatous or adenocarcinomatous portion of the neoplasm. The prognosis is poor.