Renal cyst (kidneys)
Pancreatic cyst
Peritoneal inclusion cyst (lining of the abdominal cavity) - It is a cluster of fluid-filled cysts lining the abdominal cavity of reproductive age women with a history of pelvic, abdominal surgeries, or abdominal inflammation. Those affected maybe presented with an abdominal, pelvic, lower back that lasted for months. Enteric duplication cyst

Central nervous system
Choroid plexus cyst
Colloid cyst
Pineal gland cyst (in the pineal gland in the brain)
Glial cyst
Tarlov cyst (spinal canal)

Musculoskeletal system
Aneurysmal bone cyst, a benign bone tumor with a radiographic cystic appearance. Bakers cyst or popliteal cyst (behind the knee joint)
Mucoid cyst (ganglion cysts of the digits)
Stafne static bone cyst (an anatomic variant with radiographic cystic appearance in the posterior mandible)
Subchondral cyst (cysts near the bony joints)

Seen in various locations
Dermoid cyst (seen in ovaries, testes, and many other locations, from head to tailbone)
Ganglion cyst (hand and foot joints and tendons)
Mucoid cyst (ganglion cysts of the digits)

Infectious cysts
Cysticercal cyst – an infection due to the larval stage of Taenia sp. (Crains backs)
Hydatid cyst – an infection in the liver or other parts of the body due to the larval stage of Echinococcus granulosus (tapeworm)

Neoplastic cysts
Dermoid cyst
Keratocystic odontogenic tumor
Calcifying odontogenic cyst

Treatment
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.
Pathophysiology
The exact mechanism of myositis ossificans is not clear. Inappropriate response of stem cells in the bone against the injury or inflammation causes inappropriate differentiation of fibroblasts into osteogenic cells. When a skeletal muscle is injured, inflammatory cytokines (Bone morphogenetic protein 2, Bone morphogenetic protein 4, and Transforming growth factor) are released. These cytokines stimulate the endothelial cells of the blood vessels to transform into mesenchymal stem cells. These mesenchymal stem cells then differentiate into chondrocytes, and osteoblasts, resulting in bone formation in soft tissues.The process of myositis ossificans can be divided into three stages: early, intermediate, and mature. The early phase occurs in the first four weeks of injury with inflammatory phase of bone formation. This is followed by intermediate phase of bone formation (four to eight weeks following injury) where calcification started to occur and is visible on X-rays. During the maturation phase, mature bone started to form. As the maturation continues, the bone will consolidate in the coming months and subsequently bone regression occurs. Diagnosis
Sonographic diagnosis
Calcification is typically depicted 2 weeks earlier by ultrasound (US) when compared to radiographs. The lesion develops in two distinct stages with different presentations at US. In the early stage, termed immature, it  depicts a non-specific soft tissue mass that ranges from a hypoechoic area with an outer sheet-like hyperechoic peripheral rim to a highly echogenic area with variable shadowing.