They are benign lesions and malignant degeneration is rare. They are usually treated with curettage which however have a high recurrence rate of 25%. As such if an en-bloc resection is possible this is advisable

As the condition is quite rare, opinions among experts about how to treat OKCs differ.

Treatment options:

- Wide (local) surgical excision.

- Marsupialization - the surgical opening of the (OKC) cavity and a creation of a marsupial-like pouch, so that the cavity is in contact with the outside for an extended period, e.g. three months.

- Curettage (simple excision & scrape-out of cavity).

- Peripheral ostectomy after curettage and/or enucleation.

- Simple excision.

- Carnoy's solution - usually used in conjunction with excision.

- Enucleation and cryotherapy

Chondromyxoid fibroma is a type of cartilaginous tumor.

Most cases are characterised by GRM1 gene fusion or promoter swapping. It can be associated with a translocation at t(1;5)(p13;p13).

A chondromyxoid fibroma (CMF) is an extremely rare benign cartilaginous neoplasm which accounts for < 1% bone tumours.

Complete surgical excision is the treatment of choice, associated with an excellent long term clinical outcome.

One person in every 100,000 is affected. Ollier disease is not normally diagnosed until toddler years because it is not very visible.

The deformities are managed surgically to preserve the function of the limb.

Chondroblastoma has not been known to spontaneously heal and the standard treatment is surgical curettage of the lesion with bone grafting. To prevent recurrence or complications it is important to excise the entire tumor following strict oncologic criteria. However, in skeletally immature patients intraoperative fluoroscopy may be helpful to avoid destruction of the epiphyseal plate. In patients who are near the end of skeletal growth, complete curettage of the growth plate is an option. In addition to curettage, electric or chemical cauterization (via phenol) can be used as well as cryotherapy and wide or marginal resection. Depending on the size of the subsequent defect, autograft or allograft bone grafts are the preferred filling materials. Other options include substituting polymethylmethacrylate (PMMA) or fat implantation in place of the bone graft. The work of Ramappa "et al" suggests that packing with PMMA may be a more optimal choice because the heat of polymerization of the cement is thought to kill any remaining lesion.

Both radiotherapy and chemotherapy are not commonly used. Radiotherapy has been implemented in chondroblastoma cases that are at increased risk of being more aggressive and are suspected of malignant transformation. Furthermore, radiofrequency ablation has been used, but is typically most successful for small chondroblastoma lesions (approximately 1.5 cm). Treatment with radiofrequency ablation is highly dependent on size and location due to the increased risk of larger, weight-bearing lesions being at an increased risk for articular collapse and recurrence.

Overall, the success and method of treatment is highly dependent upon the location and size of the chondroblastoma.

A chondroma is a benign cartilaginous tumor, which is encapsulated with a lobular growing pattern.

Tumor cells (chondrocytes, cartilaginous cells) resemble normal cells and produce the cartilaginous matrix (amorphous, basophilic material).

Characteristic features of this tumor include the vascular axes within the tumor, which make the distinction with normal hyaline cartilage.

Based upon location, a chondroma can be described as an enchondroma or ecchondroma.

- enchondroma - tumor grows within the bone and expands it.

- ecchondroma - grows outward from the bone and this is rare.

Treatment

- best left alone

- if it causes fractures (enchondroma) or is unsightly it should be removed by curettage and the defect filled with bone graft.

The tumor is rare, affecting adults in the 4th decade most commonly. Patients are usually younger than those who present with a lipoma. There is a slight male predominance. Hibernoma are most commonly identified in the subcutaneous and muscle tissue of the head and neck region (shoulders, neck, scapular), followed by thigh, back, chest, abdomen, and arms. In rare cases hibernoma may arise in bone tissue, however it is an incidental finding.

Based on a survey of >800, surgical removal of the entire involved kidney plus the peri-renal fat appeared curative for the majority of all types of mesoblastic nephroma; the patient overall survival rate was 94%. Of the 4% of non-survivors, half were due to surgical or chemotherapeutic treatments. Another 4% of these patients suffered relapses, primarily in the local area of surgery rare cases of relapse due to lung or bone metastasis.. About 60% of these recurrent cases had a complete remission following further treatment. Recurrent disease was treated with a second surgery, radiation, and/or chemotherapy that often vincristine and actinomycin treatment. Removal of the entire afflicted kidney plus the peri-renal fat appears critical to avoiding local recurrences. In general, patients who were older than 3 months of age at diagnosis or had the cellular form of the disease, stage III disease, or involvement of renal lymph nodes had a higher recurrence rate. Among patients with these risk factors, only those with lymph node involvement are recommended for further therapy.

It has been suggested that mesoblastic nephroma patients with lymph node involvement or recurrent disease might benefit by adding the ALK inhibitor, crizotinib, or a tyrosine kinase inhibitor, either larotrectinib or entrectinib, to surgical, radiation, and/or chemotherapy treatment regimens. These drugs inhibit NTRK3's tyrosine kinase activity. Crizotinib has proven useful in treating certain cases of acute lymphoblastic leukemia that are associated with the "ETV6-NTRK3" fusion gene while larotrectinib and entrectinib have been useful in treating various cancers (e.g. a metastatic sarcoma, papillary thyroid cancer, non-small-cell lung carcinoma, gastrointestinal stromal tumor, mammary analog secretory carcinoma, and colorectal cancer) that are driven by mutated, overly active tyrosine kinases. Relevant to this issue, a 16-month-old girl with infantile fibrosarcoma harboring the "ETV6–NTRK3" fusion gene was successfully trated with larotrectinib. The success of these drugs, howwever, will likely depend on the relative malignancy-promoting roles of ETV6-NTRK3 protein's tyrosine kinase activity, the lose of ETV6-related transcription activity accompanying formation of ETV6-NTRK3 protein, and the various trisomy chromosomes that populate mesoblastic nephroma.

An odontogenic tumor is a neoplasm of the cells or tissues that initiate odontogenic processes.

Examples include:

- Adenomatoid odontogenic tumor

- Ameloblastoma, a type of odontogenic tumor involving ameloblasts

- Calcifying epithelial odontogenic tumor

- Keratocystic odontogenic tumor

- Odontogenic myxoma

- Odontoma

Trichilemmoma (also known as "tricholemmoma") is a benign cutaneous neoplasm that shows differentiation toward cells of the outer root sheath. The lesion is often seen in the face and neck region. Multifocal occurrence is associated with Cowden syndrome, in which hamartomatous intestinal polyposis is seen in conjunction with multiple tricholemmoma lesions.

Age and gender have an effect on the incidence of these lesions; they are more prevalent in women than men (though still common in both genders), and they appear more frequently with age. Due to the standard of medical care and screening in developed countries, it is increasingly rare for primary hyperparathyroidism to present with accompanying bone disease. This is not the case in less developed nations, however, and the two conditions are more often seen together.

Osteochondromas are benign lesions and do not affect life expectancy. Complete excision of osteochondroma is curative and the reoccurrences take place when the removal of tumor is incomplete. Multiple reoccurrences in a well-excised lesion indicate that it may be malignant. The risk of malignant transformation takes place in 1–5% of individuals. If any symptoms of cancerous tumor takes place, then the patient should be evaluated by a bone specialist. No treatment is necessary for Solitary osteochondromas that are asymptomatic. Treatments for solitary osteochondroma are careful observation over time and taking regular x-rays to monitor any changes in the tumor. If the lesion is causing pain with activity, nerve or vessel impingement, or if the bone growth has fully matured and the presence of a large cartilage cap is prominent, then it is advised that the tumor be surgically removed.

Osteochondromas have a low rate of malignancy (<1%) and resection of the tumor is suggested if symptoms such as pain, limitation of movement, or impingement on nerves or vessels occur. Resection of the tumor also takes place when the tumor increases in size and progresses towards malignancy. During surgical resection, the entire lesion along with the cartilaginous cap should be removed to minimize any chances of reoccurrences. Surgical treatment becomes the sole treatment of choice if common complications such as fractures, symptoms of peripheral nerves such as paresthesia, paraplegia, peroneal neuropathy, and upper limb neuropathy take place. A prophylactic resection is suggested if the lesion lies next to a vessel.

Depending on the size and location of the tumor, the time it takes to return to normal daily activities varies between individuals. Limitation on some activities is advised if pain or discomfort persists after surgical excision.

Overall, the mainstay of the treatment for salivary gland tumor is surgical resection. Needle biopsy is highly recommended prior to surgery to confirm the diagnosis. More detailed surgical technique and the support for additional adjuvant radiotherapy depends on whether the tumor is malignant or benign.

Surgical treatment of parotid gland tumors is sometimes difficult, partly because of the anatomical relationship of the facial nerve and the parotid lodge, but also through the increased potential for postoperative relapse. Thus, detection of early stages of a tumor of the parotid gland is extremely important in terms of prognosis after surgery.

Generally, benign tumors of the parotid gland are treated with superficial(Patey's operation) or total parotidectomy with the latter being the more commonly practiced due to high incidence of recurrence. The facial nerve should be preserved whenever possible. The benign tumors of the submandibular gland is treated by simple excision with preservation of mandibular branch of the trigeminal nerve, the hypoglossal nerve, and the lingual nerve. Other benign tumors of minor salivary glands are treated similarly.

Malignant salivary tumors usually require wide local resection of the primary tumor. However, if complete resection cannot be achieved, adjuvant radiotherapy should be added to improve local control. This surgical treatment has many sequellae such as cranial nerve damage, Frey's syndrome, cosmetic problems, etc.

Usually about 44% of the patients have a complete histologic removal of the tumor and this refers to the most significant survival rate.

A myxoid liposarcoma is a malignant adipose tissue neoplasm of myxoid appearance histologically.

Myxoid liposarcomas are the second most common type of liposarcoma, representing 30–40% of all liposarcomas in the limbs; occurring most commonly in the legs, particularly the thigh, followed by the buttocks, retroperitoneum, trunk, ankle, proximal limb girdle, head and neck, and wrist. They occur in the intermuscular fascial planes or deep-seated areas. They present as a large, slow-growing, painless mass.

They are associated with a fusion between DDIT3 or "CHOP" (at 12q13.1-q13.2) and FUS or "TLS" (at 16p11.2) or EWS (at 22q12.2).

The specific translocation of FUS-DDIT3 is t(12;16)(q13;p11).

An odontogenic keratocyst is a rare and benign but locally aggressive developmental cyst. It most often affects the posterior mandible. It most commonly presents in the third decade of life.

In the WHO/IARC classification of head and neck pathology, this clinical entity had been known for years as the odontogenic keratocyst; it was reclassified as keratocystic odontogenic tumour (KCOT) from 2005 to 2017. In 2017 it reverted to the earlier name, as the new WHO/IARC classification reclassified OKC back into the cystic category. The WHO/IARC classification no longer considers it a neoplasm, because the evidence supporting that hypothesis (for example, clonality) is considered insufficient. However, this is an area of hot debate within the head and neck pathology community, and some pathologists still regard OKC as a neoplasm despite the reclassification.

Although not specific to one mode of management, lesion size, patient sex, or follow-up, the recurrence rate for chondroblastoma is relatively high, and has been shown in select studies to be dependent upon the anatomical location, method of treatment, and biological aggressiveness of the initial lesion. The rate of recurrence is highly variable, ranging between 5% and 40%, as study results are generally inconclusive. However, local recurrence for long bone lesions is around 10%, with chondroblastoma in flat bones having higher recurrence and more complications. Recurrences are more common in cases involving an open epiphyseal plate where they can be attributed to inadequate curettage to avoid damage. Lesions of the proximal femur are particularly problematic because of difficulties accessing the femoral head for complete excision. Chondroblastoma may recur in the soft tissue surrounding the initial lesion, especially in the case of incomplete curettage. Recurrences have been shown to occur between 5 months and 7 years after initial treatment and are generally treated with repeat curettage and excision of affected soft-tissue. No histological differences have been seen between recurrent and non-recurrent chondroblastomas.

Rarely, more aggressive chondroblastomas can metastasize. The most common location for metastases is the lung, with some cases also involving secondary bone sites, soft tissue, skin, or the liver. The prevalence of metastatic chondroblastoma, however, is quite low and is believed to be less than 1%. There is no relationship established between metastasis and previous surgery, non-surgical treatment, anatomical location, or patient age. Survival of patients with metastatic lesions is better when the metastases are surgically resectable, as chemotherapy has been shown to have little to no benefit. Prognosis is bleak for patients with malignant chondroblastomas that are resistant to surgery, radiation, and chemotherapy. However, patients with resectable metastases have survived for several years following diagnosis.

While recurrence is the most common complication of chondroblastoma other issues include post-surgery infection, degenerative joint disease, pathological fractures, failure of bone grafts, pre-mature epiphyseal closure, functional impairment, and malignant transformation. Complications are less common in patients presenting with chondroblastoma in accessible areas. Overall, patients with more classical chondroblastoma (appearing in long bones, typical presentation) have better prognoses than patients with atypical chondroblastoma (flat bones, skull, etc.).

Surgical excision of the lesion is done, and depending upon the clinical circumstances, this may or may not involve removal of the involved tooth. With incomplete removal, recurrence is common; some surgeons advocate curettage after extraction of teeth to decrease the overall rate of recurrence.

According to a Dutch source juvenile pilocytic astrocytoma occurs at a rate of 2 in 100,000 people. Most affected are children ages 5–14 years. According to the National Cancer Institute more than 80% of astrocytomas located in the cerebellum are low grade (pilocytic grade I) and often cystic; most of the remainder are diffuse grade II astrocytomas.

Tumors of the optic pathway account for 3.6-6% of pediatric brain tumors, 60% of which are juvenile pilocytic astrocytomas. Astrocytomas account for 50% of pediatric primary central nervous system tumors. About 80-85% of cerebellar astrocytomas are juvenile pilocytic astrocytomas.

Recent genetic studies of pilocytic astrocytomas show that some sporadic cases have gain in chromosome 7q34 involving the BRAF locus.

Trichoepithelioma is a neoplasm of the adnexa of the skin. Its appearance is similar to basal cell carcinoma.

One form has been mapped to chromosome 9p21.

Carcinoma "in situ" is, by definition, a localized phenomenon, with no potential for metastasis unless it progresses into cancer. Therefore, its removal eliminates the risk of subsequent progression into a life-threatening condition.

Some forms of CIS (e.g., colon polyps and polypoid tumours of the bladder) can be removed using an endoscope, without conventional surgical resection. Dysplasia of the uterine cervix is removed by excision (cutting it out) or by burning with a laser. Bowen's disease of the skin is removed by excision. Other forms require major surgery, the best known being intraductal carcinoma of the breast (also treated with radiotherapy). One of the most dangerous forms of CIS is the "pneumonic form" of BAC of the lung, which can require extensive surgical removal of large parts of the lung. When too large, it often cannot be completely removed, with eventual disease progression and death of the patient.

Children with cerebellar pilocytic astrocytoma may experience side effects related to the tumor itself depending on the location and related to the treatment. Strabismus.

- Symptoms related to increased pressure in the brain often disappear after surgical removal of the tumor.

- Effects on coordination and balance improved and might progressively (to completely) disappear as recovery progresses.

- Steroid-treatment is often used to control tissue swelling that may occur pre- and post-operatively.

- Children Diagnosed can also suffer long term side effects due to the type of treatment they may receive.

Pleomorphic adenoma is a common benign salivary gland neoplasm characterised by neoplastic proliferation of parenchymatous glandular cells along with myoepithelial components, having a malignant potentiality. It is the most common type of salivary gland tumor and the most common tumor of the parotid gland. It derives its name from the architectural Pleomorphism (variable appearance) seen by light microscopy. It is also known as "Mixed tumor, salivary gland type", which describes its pleomorphic appearance as opposed to its dual origin from epithelial and myoepithelial elements.

The brown tumor is a bone lesion that arises in settings of excess osteoclast activity, such as hyperparathyroidism. It is not a true neoplasm, as the term "tumor" suggests; however, it may mimic a true neoplasm. It most commonly affects the maxilla and mandible, though any bone may be affected. Brown tumours are radiolucent on x-ray.