A small dermoid cyst on the coccyx can be difficult to distinguish from a pilonidal cyst. This is partly because both can be full of hair. A pilonidal cyst is a pilonidal sinus that is obstructed. Any teratoma near the body surface may develop a sinus or a fistula, or even a cluster of these. Such is the case of Canadian Football League linebacker Tyrone Jones, whose teratoma was discovered when he blew a tooth out of his nose.

Treatment for dermoid cyst is complete surgical removal, preferably in one piece and without any spillage of cyst contents. Marsupialization, a surgical technique often used to treat pilonidal cyst, is inappropriate for dermoid cyst due to the risk of malignancy.

The association of dermoid cysts with pregnancy has been increasingly reported. They usually present the dilemma of weighing the risks of surgery and anesthesia versus the risks of untreated adnexal mass. Most references state that it is more feasible to treat bilateral dermoid cysts of the ovaries discovered during pregnancy if they grow beyond 6 cm in diameter.

Cases of lymphangioma are diagnosed by histopathologic inspection. In prenatal cases, cystic lymphangioma is diagnosed using an ultrasound; when confirmed amniocentesis may be recommended to check for associated genetic disorders.

Lymphatic malformations may be detected in the human fetus by ultrasound if they are of sufficient size. Detection of a cystic malformation may prompt further investigation, such as amniocentesis, in order to evaluate for genetic abnormalities in the fetus. Lymphatic malformations may be discovered postnatally or in older children/adults, and most commonly present as a mass or as an incidental finding during medical imaging.

Verification of the diagnosis may require more testing, as there are multiple cystic masses that arise in children. Imaging, such as ultrasound or MRI, may provide more information as to the size and extent of the lesion.

Treatment ranges from simple enucleation of the cyst to curettage to resection. There are cysts—e.g., buccal bifurcation cyst—that resolve on their own, in which just close observation may be employed, unless it is infected and symptomatic.

Cysts from 1–5 mm on CT or ultrasound are typically too small to characterize and considered benign. No further imaging follow-up is recommended for these lesions. Cysts from 6–9 mm require a single follow-up in 2–3 years, preferably with MRCP to better evaluate the pancreatic duct. If stable at follow-up, no further imaging follow-up is recommended. For cysts from 1–1.9 cm follow-up is suggested with MRCP or multiphasic CT in 1–2 years. If stable at follow-up, the interval of imaging follow-up is increased to 2–3 years. Cysts from 2–2.9 cm have more malignant potential, and a baseline endoscopic ultrasound is suggested, followed by MRCP or multiphasic CT in 6–12 months. If patients are young, surgery may be considered to avoid the need for prolonged surveillance. If these cysts are stable at follow-up, interval imaging follow-up can be done in 1–2 years.

The prognosis for lymphangioma circumscriptum and cavernous lymphangioma is generally excellent. This condition is associated with minor bleeding, recurrent cellulitis, and lymph fluid leakage. Two cases of lymphangiosarcoma arising from lymphangioma circumscriptum have been reported; however, in both of the patients, the preexisting lesion was exposed to extensive radiation therapy.

In cystic hygroma, large cysts can cause dysphagia, respiratory problems, and serious infection if they involve the neck. Patients with cystic hygroma should receive cytogenetic analysis to determine if they have chromosomal abnormalities, and parents should receive genetic counseling because this condition can recur in subsequent pregnancies.

Complications after surgical removal of cystic hygroma include damage to the structures in the neck, infection, and return of the cystic hygroma.

The aneurysmal bone cyst is a neoplastic cyst, more specifically, an aggressive lesion with radiographic cystic appearance.

Management of most fetal SCTs involves watchful waiting prior to any treatment. An often used decision tree is as follows:

- Perform detailed ultrasound exam including fetal echocardiogram and Doppler flow analysis

- If fetal high output failure, placentomegaly, or hydrops

- If fetus not mature, perform pregnancy termination or fetal intervention

- Else fetus mature, perform emergency Cesarean section

- Else no emergent problems, perform serial non-stress tests and ultrasound biophysical profiles and plan delivery, as follows

- If emergent problems develop, return to top of decision tree

- Else if SCT over 5–10 cm or polyhydramnios, perform early (37 weeks gestation) elective Cesarean section

- Else SCT small and no complications, permit term spontaneous vaginal delivery

Emergent problems include maternal mirror syndrome, polyhydramnios, and preterm labor. Poor management decisions, including interventions that are either premature or delayed, can have dire consequences. A very small retrospective study of 9 babies with SCTs greater than 10 cm diameter reported slightly higher survivorship in babies remaining in utero slightly longer.

In many cases, a fetus with a small SCT (under 5 or 10 cm) may be delivered vaginally. Prior to the advent of prenatal detection and hence scheduled C-section, 90% of babies diagnosed with SCT were born full term.

SCTs are very rare in adults, and as a rule these tumors are benign and have extremely low potential for malignancy. This estimation of potential is based on the idea that because the tumor existed for decades prior to diagnosis, without becoming malignant, it has little or no potential to ever become malignant. For this reason, and because coccygectomy in adults has greater risks than in babies, some surgeons prefer not to remove the coccyx of adult survivors of SCT. There are case reports of good outcomes.

Treatment ranges from simple enucleation of the cyst to curettage to resection. For example, small radicular cyst may resolved after successful endodontic ("root-canal") treatment. Because of high recurrence potential and aggressive behaviour, curettage is recommended for keratocyst. However, the conservative enucleation is the treatment of choice for most odontogenic cysts. The removed cyst must be evaluated by pathologist to confirm the diagnosis, and to rule out other neoplastic lesions with similar clinical or radiographic features (e.g., cystic or solid ameloblastoma, central mucoepidermoid carcinoma). There are cysts, e.g. buccal bifurcation cyst with self-resolation nature, in which close observation can be employed unless the cyst is infected and symptomatic.

Although often described as benign, a teratoma does have malignant potential. In a UK study of 351 infants and children diagnosed with "benign" teratoma reported 227 with MT, 124 with IT. Five years after surgery, event-free survival was 92.2% and 85.9%, respectively, and overall survival was 99% and 95.1%. A similar study in Italy reported on 183 infants and children diagnosed with teratoma. At 10 years after surgery, event free and overall survival were 90.4% and 98%, respectively.

Depending on which tissue(s) it contains, a teratoma may secrete a variety of chemicals with systemic effects. Some teratomas secrete the "pregnancy hormone" human chorionic gonadotropin (βhCG), which can be used in clinical practice to monitor the successful treatment or relapse in patients with a known HCG-secreting teratoma. This hormone is not recommended as a diagnostic marker, because most teratomas do not secrete it. Some teratomas secrete thyroxine, in some cases to such a degree that it can lead to clinical hyperthyroidism in the patient. Of special concern is the secretion of alpha-fetoprotein (AFP); under some circumstances AFP can be used as a diagnostic marker specific for the presence of yolk sac cells within the teratoma. These cells can develop into a frankly malignant tumor known as yolk sac tumor or endodermal sinus tumor.

Adequate follow-up requires close observation, involving repeated physical examination, scanning (ultrasound, MRI, or CT), and measurement of AFP and/or βhCG.

A baby with a prenatally diagnosed cystic hygroma should be delivered in a major medical center equipped to deal with neonatal complications, such as a neonatal intensive care unit. An obstetrician usually decides the method of delivery. If the cystic hygroma is large, a cesarean section may be performed. After birth, infants with a persistent cystic hygroma must be monitored for airway obstruction. A thin needle may be used to reduce the volume of the cystic hygroma to prevent facial deformities and airway obstruction. Close observation of the baby by a neonatologist after birth is recommended. If resolution of the cystic hygroma does not occur before birth, a pediatric surgeon should be consulted.

Cystic hygromas that develop in the third trimester, after thirty weeks gestation, or in the postnatal period are usually not associated with chromosome abnormalities. There is a chance of recurrence after surgical removal of the cystic hygroma. The chance of recurrence depends on the extent of the cystic hygroma and whether its wall was able to be completely removed.

Treatments for removal of cystic hygroma are surgery or sclerosing agents which include:

- Bleomycin

- Doxycycline

- Ethanol (pure)

- Picibanil (OK-432)

- Sodium tetradecyl sulfate

Extraspinal ependymoma, usually considered to be a glioma (a type of non-germ cell tumor), may be an unusual form of mature teratoma.

Diagnosis is usually made by ultrasonography showing a solid ovarian lesion, or, on some occasions, mixed tumors with solid and cystic components. Computed tomography and magnetic resonance imaging can also be used to diagnose fibromas.

In a series of 16 patients, 5 (28%) showed elevated levels of CA-125.

The standard treatment of COC is enucleation and curettage (E&C). Recurrence following E&C is rare.

Serous cystic neoplasms can come to clinical attention in a variety of ways. The most common symptoms are very non-specific and include abdominal pain, nausea and vomiting. In contrast to many of the other tumors of the pancreas, patients rarely develop jaundice (a yellowing of the skin and eyes caused by obstruction of the bile duct), or weight loss. These signs and symptoms are not specific for a serous cystic neoplasm, making it more difficult to establish a diagnosis. Doctors will therefore often order additional tests.

Once a doctor has reason to believe that a patient may have serous cystic neoplasm, he or she can confirm that suspicion using one of a number of imaging techniques. These include computerized tomography (CT), endoscopic ultrasound (EUS), and magnetic resonance cholangiopancreatography (MRCP). These tests will reveal a cystic mass within the pancreas. The cysts do not communicate with the larger pancreatic ducts. In some cases a fine needle aspiration (FNA) biopsy can be obtained to confirm the diagnosis. Fine needle aspiration biopsy can be performed through an endoscope at the time of endoscopic ultrasound, or it can be performed through the skin using a needle guided by ultrasound or CT scanning.

A growing number of patients are now being diagnosed before they develop symptoms (asymptomatic patients). In these cases, the lesion in the pancreas is discovered accidentally (by chance) when the patient is being scanned (x-rayed) for another reason.

Cystic nephromas are diagnosed by biopsy or excision. It is important to correctly diagnose them as, radiologically, they may mimic the appearance of a renal cell carcinoma that is cystic.

Usually the lesion is surgically removed. Primarily, there is concern that the lesion identified in a patient could be cancerous, but there is also the risk of torsion, and possibly the development of symptoms. A stable lesion, however, could be clinically followed.

Benign fibromas may, but need not be, removed. Removal is usually a brief outpatient procedure.

Unilocular radiolucency may be seen and mutilocular also, and mixed too .irregular calcifications may be seen in some cases.

Mucinous cystadenomas make up 15-20% of all ovarian tumors. They often become very large and can extend up into the abdomen.

These tumors are usually evaluated using ultrasound, CT scan, or MRI. Findings on imaging studies are nonspecific. These ovarian tumors are usually multi-septated, cystic masses with thin walls. They also contain varying amounts of solid tissue which consists of proliferating stromal tissue, papillae, or malignant tumor cells.

Benign mucinous cystadenomas compose 80% of mucinous ovarian tumors and 20-25% of benign ovarian tumors overall. The peak incidence occurs between 30-50 years of age. Benign tumors are bilateral in 5-10% of cases.

Odontogenic cyst are a group of jaw cysts that are formed from tissues involved in odontogenesis (tooth development). Odontogenic cysts are closed sacs, and have a distinct membrane derived from rests of odontogenic epithelium. It may contain air, fluids, or semi-solid material. Intra-bony cysts are most common in the jaws, because the mandible and maxilla are the only bones with epithelial components. That odontogenic epithelium is critical in normal tooth development. However, epithelial rests may be the origin for the cyst lining later.

Not all oral cysts are odontogenic cyst. For example, mucous cyst of the oral mucosa and nasolabial duct cyst are not of odontogenic origin.

In addition, there are several conditions with so-called (radiographic) 'pseudocystic appearance' in jaws; ranging from anatomic variants such as Stafne static bone cyst, to the aggressive aneurysmal bone cyst.

For surface epithelial-stromal tumors, the most common sites of metastasis are the pleural cavity (33%), the liver (26%), and the lungs (3%).

A pancreatic cyst is a fluid filled sac within the pancreas.

Causes range from benign to malignant. Pancreatic pseudocysts can occur in the setting of pancreatitis, though they are only reliably diagnosed 6 weeks after the episode of acute pancreatitis.

Benign tumors such as serous cystadenomas can occur. Main branch intraductal papillary mucinous neoplasms (IPMNs) are associated with dilatation of the main pancreatic duct, while side branch IPMNs are typically benign, and not associated with dilatation. MRCP can help distinguish the position of the cysts relative to the pancreatic duct, and direct appropriate treatment and follow-up. The most common malignancy that can present as a pancreatic cyst is a mucinous cystic neoplasm.