Magnetic resonance imaging is the modality of choice for diagnosis of meniscal cysts. In their most subtle form, meniscal cysts present as focal areas of high signal intensity within a swollen meniscus. It is not uncommon for radiologists to miss this type of meniscal cyst because the signal intensity is not quite as great as fluid on T2 weighted sequences.2 When this fluid is extruded into the adjacent soft tissues, the swollen meniscus subsequently assumes a more normal shape, and the extruded fluid demonstrates a higher T2 signal typical of parameniscal cysts.

Medial meniscus horizontal tear extending into a meniscal cyst.

Sagittal T2 images of a medial meniscus horizontal tear extending into a meniscal cyst.

Large medial meniscus cyst.

Treatment of meniscal cysts consists of a combination of cyst decompression (intraarticular decompression versus open cystectomy) and arthroscopic repair of any meniscal abnormalities. Success rates are significantly higher when both the cyst and meniscal tear are treated compared to treating only one disease process.

Diagnosis is by examination. A Baker's cyst is easier to see from behind with the patient standing with knees fully extended. It is most easily palpated (felt) with the knee partially flexed. Diagnosis is confirmed by ultrasonography, although if needed and there is no suspicion of a popliteal artery aneurysm then aspiration of synovial fluid from the cyst may be undertaken with care. An MRI image can reveal presence of a Baker's cyst.

An infrequent but potentially life-threatening complication, which may need to be excluded by blood tests and ultrasonography, is a deep vein thrombosis (DVT). Quick assessment of the possibility of DVT may be required where a Baker's cyst has compressed vascular structures, causing leg edema, as this sets up conditions for a DVT to develop.

A burst cyst commonly causes calf pain, swelling and redness that may mimic thrombophlebitis.

Ganglion cysts are diagnosed easily, as they are visible and pliable to touch.

Radiographs in AP and lateral views should be obtained to exclude any more serious underlying pathology. Ultrasonography (US) may be used to increase diagnostic confidence in clinically suspected lesions or to depict cysts, because intratendinous ganglia are readily distinguished from extratendinous ganglia during dynamic ultrasonography, as microscopically, ganglionic cysts are thin-walled cysts containing clear, mucinous fluid.

A pilonidal cyst can resemble a dermoid cyst, a kind of teratoma (germ cell tumor). In particular, a pilonidal cyst in the gluteal cleft can resemble a sacrococcygeal teratoma. Correct diagnosis is important because all teratomas require complete surgical excision, if possible without any spillage, and consultation with an oncologist.

Besides the frequent choice to leave the cyst in place, surgical treatments remain the primary elective option for treatment of ganglion cysts. The progression of ganglion surgery worldwide is to use an arthroscopic or mini-opening method. Alternatively, a hypodermic needle may be used to drain the fluid from the cyst (via aspiration) and a corticosteroid may be injected after the cyst is empty; however, if the fluid has thickened, owing to the passage of time, this treatment is not always effective.

There is a recurrence rate of approximately 50% following needle drainage (via aspiration) of ganglion cysts.

One common and traditional method of treatment for a ganglion cyst was to strike the lump with a large and heavy book, causing the cyst to rupture and drain into the surrounding tissues. Historically, a Bible was the largest or only book in any given household, and was often employed for this treatment. This led to the former nickname of "Bible bumps" or "Gideon's disease" for these cysts. This treatment risks injuring the patient.

a nuclear imaging method to evaluate any degenerative and/or arthritic changes in the joints; to detect bone diseases and tumors; to determine the cause of bone pain or inflammation. This test is to rule out other cysts (which are quite unusual)

CT scans use x-rays and computer technology to produce accurate axial, coronal, and sagittal images. CT scans are more detailed than x-rays because they can create images that show fat, muscles, organs, and bones.

The diagnostic process typically begins with a medical history workup followed by a medical examination by a physician. Imaging tests, such as CT scans and MRIs, help provide a clearer picture. The physician typically looks for fluid (or other bodily substance) filled sacs to appear in the scans, as is shown in the CT scan of a colloid cyst. A primary health care provider will refer an individual to a neurologist or neurosurgeon for further examination. Other diagnostic methods include radiological examinations and macroscopic examinations. After a diagnosis has been made, immunohistochemistry may be used to differentiate between epithelial cysts and arachnoid cysts. These examinations are useful to get a general idea of possible treatment options, but can be unsatisfactory to diagnose CNS cysts. Professionals still do not fully understand how cysts form; however, analyzing the walls of different cyst types, using electron microscopes and light microscopes, has proven to be the best diagnostic tool. This has led to more accurate cyst classification and correct course of action for treatments that are cyst specific. In the past, before imaging scans or tests were available, medical professionals could only diagnose cysts via exploratory surgery.

Baker's cysts usually require no treatment unless they are symptomatic. It is very rare that the symptoms are actually coming from the cyst. In most cases, there is another disorder in the knee (arthritis, meniscal (cartilage) tear, etc.) that is causing the problem. Initial treatment should be directed at correcting the source of the increased fluid production. Often rest and leg elevation are all that is needed. If necessary, the cyst can be aspirated to reduce its size, then injected with a corticosteroid to reduce inflammation. Surgical excision is reserved for cysts that cause a great amount of discomfort to the patient. A ruptured cyst is treated with rest, leg elevation, and injection of a corticosteroid into the knee.

Baker's cysts in children, unlike in older people, nearly always disappear with time, and rarely require excision.

Ice pack therapy may sometimes be an effective way of controlling the pain related to Baker's cyst. Heat is also commonly used. A knee brace can offer support giving the feel of stability in the joint.

Rest and specific exercise

Many activities can put strain on the knee, and cause pain in the case of Baker's cyst. Avoiding activities such as squatting, kneeling, heavy lifting, climbing, and even running can help prevent pain. Despite this, some exercises can help relieve pain, and a physiotherapist may instruct on stretching and strengthening the quadriceps and/or the patellar ligament.

Clinical features can be found in the subhyoid portion of the tract and 75% present as midline swellings. The remainder can be found as far lateral as the lateral tip of the hyoid bone.

Typically, the cyst will move upwards on protrusion of the tongue, given its attachment to the embryonic duct, as well as on swallowing, due to attachment of the tract to the foramen caecum.

Diagnosis is principally by MRI. Frequently, arachnoid cysts are incidental findings on MRI scans performed for other clinical reasons. In practice, diagnosis of symptomatic arachnoid cysts requires symptoms to be present, and many with the disorder never develop symptoms.

Additional clinical assessment tools that can be useful in evaluating a patient with arachnoid cysts include the mini-mental state examination (MMSE), a brief questionnaire-based test used to assess cognition.

Diagnosis of a thyroglossal duct cyst requires a medical professional, and is usually done by a physical examination. It is important to identify whether or not the thyroglossal cyst contains any thyroid tissue, as it can define the degree of cyst that is being dealt with.

Diagnostic procedures for a thyroglossal cyst include:

Treatment may include antibiotic therapy, hot compresses and application of depilatory creams. In more severe cases, the cyst may need to be lanced or treated surgically. Lancing is performed using a local anesthesia, with healing time generally under one week. The most conservative surgical treatment, Bascom's Pit Picking procedure, is a relatively simple outpatient option that can be performed in a physician's office, involves minimal pain and requires only a few days healing. Although this procedure is much less invasive than the alternatives, it is not regularly practiced in the US. The Pit Picking procedure provides good results, fast recovery, and in instances where it is unsuccessful, other options for more invasive surgery can still be performed.

The more common course for surgical treatment is for the cyst to be surgically excised (along with pilonidal sinus tracts). Post-surgical wound packing may be necessary, and packing typically must be replaced once daily for 4 to 8 weeks. In some cases, two years may be required for complete granulation to occur. Sometimes the cyst is resolved via surgical marsupialization.

Surgeons can also excise the sinus and repair with a reconstructive flap technique, such as a "cleft lift" procedure or Z-plasty, usually done under general anesthetic. This approach is especially useful for complicated or recurring pilonidal disease, leaves little scar tissue and flattens the region between the buttocks, reducing the risk of recurrence. This approach typically results in a more rapid recovery than the traditional surgery, however there are fewer surgeons trained in the cleft lift procedure and thus, it may not be as accessible to patients, depending on their geographic location. Meta analysis shows recurrence rates were lower in open healing than with primary closure (RR 0.60, 95% CI 0.42 to 0.87) at the expense of time to healing. Pilonidal cysts recur and do so more frequently if the surgical wound is sutured in the midline, as opposed to away from the midline, which obliterates the natal cleft and removes the focus of shearing stress. An incision lateral to the intergluteal cleft is therefore preferred, especially given the poor healing of midline incisions in this region.

An attractive minimally invasive technique is to treat pilonidal sinus with fibrin glue. This technique is less painful than traditional excisional techniques and flaps, can be performed under local or general anaesthesia, does not require dressings or packing and allows return to normal activities within 1 to 2 days. Long term outcome and recurrence rates are not dissimilar to more invasive techniques in 5 year follow up in a small randomised controlled trial.

Fibrin glue has also been shown to be better than more invasive alternatives in the treatment of pilonidal sinus disease in children, where a quick return to normal activities and minimal postoperative pain are especially important.

A minimally invasive surgical technique, was developed in Israel by Moshe Gips et al.,2008. and is similar to the pit picking technique first described by Bascom in 1980 In this procedure, trephines or biopsy punches which only "core out" and remove the diseased tissue and cyst are used, leaving only small holes to heal. Work or school activities will be resumed in one or two days, without or with minimal postoperative pain. The two procedures have been successfully combined by L. Basso in Rome (Italy).

While the recovery rate is positive for most, some suffer long term effects. Recorded instances include patients with continued postoperative pain for years following the surgical procedure. Primary complaints included pain when sitting for long period of times or following abrasive contact with the lower back and buttocks.

Colloid cysts can be diagnosed by symptoms presented. Additional testing will be required and the colloid cyst symptoms can resemble those of other diseases. MRI and CT scans are often used to confirm diagnosis.

The clinical management of a cyst of Montgomery depends upon the symptoms of the patient.

If there are no signs of infection, a cyst of Montgomery can be observed, because more than 80% resolve spontaneously, over only a few months. However, in some cases, spontaneous resolution may take up two years. In such cases, a repeat ultrasonography may become necessary. If, however, the patient has signs of an infection, for example reddening (erythema), warmth, pain and tenderness, a treatment for mastitis can be initiated, which may include antibiotics and non-steroidal anti-inflammatory drugs (NSAIDs). With treatment, inflammatory changes usually disappear quickly. In rare cases, drainage may become necessary. A surgical treatment of a cyst of Montgomery, i.e. a resection, may become necessary only if a cyst of Montgomery persists, or the diagnosis is questioned clinically.

The prognosis seems to be excellent. In one series, all adolescent patients with a cyst of Montgomery had a favourable outcome.

A cyst of Montgomery may be asymptomatic. Yet, a cyst of Montgomery usually is diagnosed when a female patient, 10–20 years of age, complains to a healthcare professional of breast pain (mastalgia), inflammation or a palpable nodule in the breast. The diagnosis is made clinically, when a palpable nodule is felt in the retroareolar area.

The diagnosis can be confirmed with ultrasonography, frequently showing a simple cyst in the retroareolar area. In some patients, multiple cysts or bilateral cysts may exist. Cysts of Montgomery may have liquid content with an echogenic or calcific sediment.

Epidermoid cysts are usually diagnosed when a person notices a bump on their skin and seeks medical attention. The definitive diagnosis is made after excision by a pathologist based on microscopic appearance of a cystic lesion lined by cornified epithelium containing lamellated keratin without calcifications. They can also be seen as isointense lesions on MRI or hyperintensities on FLAIR.

Most cysts are discovered as a chance finding on routine dental radiography. On an x-ray, cysts appear as radiolucent (dark) areas with radiopaque (white) borders. Cysts are usually unilocular, but may also be multilocular. Sometimes aspiration is used to aid diagnosis of a cystic lesion, e.g. fluid aspirate from a radicular cyst may appear straw colored and display shimmering due to cholesterol content. Almost always, the cyst lining is sent to a pathologist for histopathologic examination after it has been surgically removed. This means that the exact diagnosis of the type of cyst is often made in retrospect.

Segond and reverse Segond fractures are characterized by a small avulsion, or "chip", fragment of characteristic size that is best seen on plain radiography in the anterior-posterior plane. The chip of bone may be very difficult to see on the plain x-ray exam, and may be better seen on computed tomography. MRI may be useful for visualization of the associated bone marrow edema of the underlying tibial plateau on fat- saturated T2W and STIR images, as well as the associated findings of ligamentous and/or meniscal injury.

Other conditions that may present similarly include hidradenoma papilliferum, lipomas, epidermoid cysts and Skene's duct cysts among others. In those who are more than 40 years of age a biopsy may be recommended to ensure cancer is not present.

Nasopalatine duct cysts usually present as asymptomatic palatal swellings, but they may rarely be accompanied by pain and/or purulent discharge. The cysts are generally treated by .

Most arachnoid cysts are asymptomatic, and do not require treatment. Where complications are present, leaving arachnoid cysts untreated, may cause permanent severe neurological damage due to the progressive expansion of the cyst(s) or hemorrhage (bleeding). However, with treatment most individuals with symptomatic arachnoid cysts do well.

More specific prognoses are listed below:

- Patients with impaired preoperative cognition had postoperative improvement after surgical decompression of the cyst.

- Surgery can resolve psychiatric manifestations in selected cases.

A non-vital tooth is necessary for the diagnosis of a periapical cyst, meaning the nerve has been removed by root canal therapy. Oral examination of the surrounding intraoral anatomical structures should be palpated to identify the presence of bone expansion or displacement of tooth roots as well as crepitus noises during examination, indicating extensive bone damage. Bulging of the buccal or lingual cortical plates may be present. Age of occurrence in the patient, the location of the cyst, the edges of cystic contours, and the impact that the cyst has on adjacent structures must all be considered for proper diagnosis.

Several lesions can appear similarly in radiographic appearance. Intraoral X-rays or a 3-D cone beam scan of the affected area can be used to obtain radiological images and confirm diagnosis of cysts in the periapical area. Circular or ovoid radiolucency surrounding the root tip of approximately 1-1.5 cm in diameter is indicative of the presence of a periapical cyst. The border of the cyst is seen as a narrow opaque margin contiguous with the lamina dura. In cysts that are actively enlarging, peripheral areas of the margin may not be present. Periapical cysts have a characteristic unilocular shape on radiographs. There is also a severe border of cortication between the cyst and surrounding bone. Pseudocysts, on the other hand, have a fluid filled cavity but are not lined by epithelium, therefore they have a less severe and more blurred border between the fluid and bony surroundings.

Resorption of the roots of affected teeth may also be observed as the absence of portions of normal root structures.

Infected cysts will produce a positive percussion test on the affected tooth as well as a negative response to the pulp test. There may also be visible swelling in the overlying soft tissues. The affected tooth may also exhibit discoloration.

A neurosurgeon may open a portion of the body and insert a shunt into cerebral spinal fluid (CSF) filled cysts to allow drainage into CSF pathways. The fluid from the cyst is then drained into the abdomen, the body reabsorbs the fluid (reabsorption of fluid does not cause any harm). This type of surgical treatment is often performed to relieve pressure on the brain from a cyst within the cerebral cortex.