Chondromyxoid fibromas can share characteristics with chondroblastomas with regards to histologic and radiographic findings. However they more commonly originate from the metaphysis, lack calcification and have a different histologic organization pattern. Other differential diagnoses for chondroblastoma consist of giant cell tumors, bone cysts, eosinophilic granulomas, clear cell chondrosarcomas, and enchondromas (this list is not exhaustive).

Recurrence rate of solid form of tumour is lower than classic form.

Chondroid differentiation is a common feature of chondroblastoma. A typical histological appearance consists of a combination of oval mononuclear and multi-nucleated osteoclast-type giant cells. However this is not a prerequisite for diagnosis, as cells with epithelioid characteristics have been observed in lesions of the skull and facial bones. A "chicken-wire" appearance is characteristic of chondroblastoma cells and is the result of dystrophic calcification that may surround individual cells. Although, calcification may not be present and is not a prerequisite for diagnosis. Mitotic figures can be observed in chondroblastoma tissue but are not considered atypical in nature, and therefore, should not be viewed as a sign of a more serious pathology. There is no correlation between mitotic activity and location of the lesion. Furthermore, the presence of atypical cells is rare and is not associated with malignant chondroblastoma. There are no discernible histological differences observed when comparing the aggressive form of chondroblastoma that can cause recurrence or metastases with its less aggressive, benign, counterpart.

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

Family physicians and orthopedists rarely see a malignant bone tumor (most bone tumors are benign). The route to osteosarcoma diagnosis usually begins with an X-ray, continues with a combination of scans (CT scan, PET scan, bone scan, MRI) and ends with a surgical biopsy. A characteristic often seen in an X-ray is Codman's triangle, which is basically a subperiosteal lesion formed when the periosteum is raised due to the tumor. Films are suggestive, but bone biopsy is the only definitive method to determine whether a tumor is malignant or benign.

Most times, the early signs of osteosarcoma are caught on X-rays taken during routine dental check-ups. Osteosarcoma frequently develops in the mandible (lower jaw); accordingly, Dentist are trained to look for signs that may suggest osteosarcoma. Even though radiographic findings for this cancer vary greatly, one usually sees a symmetrical widening of the periodontal ligament space. If the dentist has reason to suspects osteosarcoma or another underlying disorder, he or she would refer the patient to an Oral & Maxillofacial surgeon for biopsy. A biopsy of suspected osteosarcoma outside of the facial region should be performed by a qualified orthopedic oncologist. The American Cancer Society states: "Probably in no other cancer is it as important to perform this procedure properly. An improperly performed biopsy may make it difficult to save the affected limb from amputation." It may also metastasise to the lungs, mainly appearing on the chest X-ray as solitary or multiple round nodules most common at the lower regions.

Following conditions are excluded before diagnosis can be confirmed:

- Unicameral bone cyst

- Giant cell tumor

- Telangiectatic osteosarcoma

- Secondary aneurysmal bone cyst

Plain film

often seen as a lobulated, eccentric radiolucent lesion

long axis parallel to long axis of long bone

no periosteal reaction (unless a complicating fracture present)

geographic bone destruction: almost 100%

well defined sclerotic margin: 86%

there can be presence of septations (pseudotrabeculation): 57% 2

there can be presence of matrix calcification in a small proportion of cases: 12.5%1

MRI

MR features are often not particularly specific. Signal characteristics include

T1 - low signal

T1 C+ (Gd) -

the majority (~70%) tend to show peripheral nodular enhancement

~ 30% diffuse contrast enhancement and this can be either homogeneous or heterogeneous 19

T2 - high signal

Bone scan

A scintigraphic "doughnut sign" has been described in this tumour type 11. However, this is very non-specific and can be found in a plethora of other bone lesions.

The initial evaluation involves radiographs (X-rays) of the affected site, but the only way to confirm the diagnosis is by sampling the tissue via biopsy or needle aspiration.

Most countries have standard newborn exams that include a hip joint exam screening for early detection of hip dysplasia.

Sometimes during an exam a "click" or more precisely "clunk" in the hip may be detected (although not all clicks indicate hip dysplasia). When a hip click (also known as "clicky hips" in the UK) is detected, the child's hips are tracked with additional screenings to determine if developmental dysplasia of the hip is caused.

Two maneuvers commonly employed for diagnosis in neonatal exams are the Ortolani maneuver and the Barlow maneuver.

In order to do the Ortolani maneuver it is recommended that the examiner put the newborn baby in a position in which the contralateral hip is held still while the thigh of the hip being tested is abducted and gently pulled anteriorly. If a "clunk" is heard (the sound of the femoral head moving over the acetabulum), the joint is normal, but absence of the "clunk" sound indicates that the acetabulum is not fully developed. The next method that can be used is called the Barlow maneuver. It is done by adducting the hip while pushing the thigh posteriorly. If the hip goes out of the socket it means it is dislocated, and the newborn has a congenital hip dislocation. The baby is laid on its back for examination by separation of its legs. If a clicking sound can be heard, it indicates that the baby may have a dislocated hip. It is highly recommended that these maneuvers be done when the baby is not fussing, because the baby may inhibit hip movement.

The condition can be confirmed by ultrasound and X-ray. Ultrasound imaging yields better results defining the anatomy until the cartilage is ossified. When the infant is around 3 months old a clear roentgenographic image can be achieved. Unfortunately the time the joint gives a good x-ray image is also the point at which nonsurgical treatment methods cease to give good results. In x-ray imaging dislocation may be indicated if the Shenton's line (an arc drawn from the medial aspect of the femoral neck through the superior margin of the obturator foramen) does not result in a smooth arc. However, in infants this line can be unreliable as it depends on the rotation of the hip when the image is taken ()

Asymmetrical gluteal folds and an apparent limb-length inequality can further indicate unilateral hip dysplasia. Most vexingly, many newborn hips show a certain ligamentous laxity, on the other hand severely malformed joints can appear stable. That is one reason why follow-up exams and developmental monitoring are important. Frequency and methods of routine screenings in children is still in debate however physical examination of newborns followed by appropriate use of hip ultrasound is widely accepted.

The Harris hip score (developed by William H. Harris MD, an orthopedist from Massachusetts) is one way to evaluate hip function following surgery. Other scoring methods are based on patients' evaluation like e.g. the Oxford hip score, HOOS and WOMAC score. Children's Hospital Oakland Hip Evaluation Scale (CHOHES) is a modification of the Harris hip score that is currently being evaluated.

Hip dysplasia can develop in older age. Adolescents and adults with hip dysplasia may present with hip pain and in some cases hip labral tears. X-rays are used to confirm a diagnosis of hip dysplasia. CT scans and MRI scans are occasionally used too.

Usually—depending on the interview of the patient and after a clinical exam which includes a neurological exam, and an ophthalmological exam—a CT scan and or MRI scan will be performed. A special dye may be injected into a vein before these scans to provide contrast and make tumors easier to identify. The neoplasm will be clearly visible.

If a tumor is found, it will be necessary for a neurosurgeon to perform a biopsy of it. This simply involves the removal of a small amount of tumorous tissue, which is then sent to a (neuro)pathologist for examination and staging. The biopsy may take place before surgical removal of the tumor or the sample may be taken during surgery.

Depending on the pet's unique condition, there are several treatment options, including surgery, chemotherapy and radiation therapy. Treating the pain adequately is also of crucial importance to improve the pet's quality of life, especially if amputation is not performed.

In 1979 Dr. John F. Crowe et al. proposed a classification to define the degree of malformation and dislocation. Grouped from least severe Crowe I dysplasia to most severe Crowe IV. This classification is very useful for studying treatment results.

Rather than using the Wiberg angle because it makes it difficult to quantify the degree of dislocation they used 3 key elements to determine the degree of subluxation: A reference line at the lower rim of the "teardrop", junction between the femoral head and neck of the respective joint and the height of the pelvis (vertical measurement). They studied anteroposterior pelvic x-rays and drew horizontal lines through the lower rim of a feature called "teardrop". The distance between this line and the middle lines of the junction between femur head and neck gave them a measure of the degree of femur head subluxation. They further established that a "normal" diameter of the femur head measures 20% of the height of the pelvis. If the middle line of the neck-head junction was more than 10% of the pelvis height above the reference line they considered the joint to be more than 50% dislocated.

The following types resulted:

The diagnosis is a combination of clinical suspicion plus radiological investigation. Children with a SCFE experience a decrease in their range of motion, and are often unable to complete hip flexion or fully rotate the hip inward. 20-50% of SCFE are missed or misdiagnosed on their first presentation to a medical facility. SCFEs may be initially overlooked, because the first symptom is knee pain, referred from the hip. The knee is investigated and found to be normal.

The diagnosis requires x-rays of the pelvis, with anteriorposterior (AP) and frog-leg lateral views. The appearance of the head of the femur in relation to the shaft likens that of a "melting ice cream cone", visible with Klein's line. The severity of the disease can be measured using the Southwick angle.

A complete radical, surgical, "en bloc" resection of the cancer, is the treatment of choice in osteosarcoma. Although about 90% of patients are able to have limb-salvage surgery, complications, particularly infection, prosthetic loosening and non-union, or local tumor recurrence may cause the need for further surgery or amputation.

Mifamurtide is used after a patient has had surgery to remove the tumor and together with chemotherapy to kill remaining cancer cells to reduce the risk of cancer recurrence. Also, the option to have rotationplasty after the tumor is taken out exists.

Patients with osteosarcoma are best managed by a medical oncologist and an orthopedic oncologist experienced in managing sarcomas. Current standard treatment is to use neoadjuvant chemotherapy (chemotherapy given before surgery) followed by surgical resection. The percentage of tumor cell necrosis (cell death) seen in the tumor after surgery gives an idea of the prognosis and also lets the oncologist know if the chemotherapy regimen should be altered after surgery.

Standard therapy is a combination of limb-salvage orthopedic surgery when possible (or amputation in some cases) and a combination of high-dose methotrexate with leucovorin rescue, intra-arterial cisplatin, adriamycin, ifosfamide with mesna, BCD (bleomycin, cyclophosphamide, dactinomycin), etoposide, and muramyl tripeptide. Rotationplasty may be used. Ifosfamide can be used as an adjuvant treatment if the necrosis rate is low.

Despite the success of chemotherapy for osteosarcoma, it has one of the lowest survival rates for pediatric cancer. The best reported 10-year survival rate is 92%; the protocol used is an aggressive intra-arterial regimen that individualizes therapy based on arteriographic response. Three-year event-free survival ranges from 50% to 75%, and five-year survival ranges from 60% to 85+% in some studies. Overall, 65–70% patients treated five years ago will be alive today. These survival rates are overall averages and vary greatly depending on the individual necrosis rate.

Filgrastim or pegfilgrastim help with white blood cell counts and neutrophil counts. Blood transfusions and epoetin alfa help with anemia. Computational analysis on a panel of Osteosarcoma cell lines identified new shared and specific therapeutic targets (proteomic and genetic) in Osteosarcoma, while phenotypes showed an increased role of tumor microenvironments.

Typically, radiographs are taken of the hip from the front (AP view), and side (lateral view). Frog leg views are to be avoided, as they may cause severe pain and further displace the fracture. In situations where a hip fracture is suspected but not obvious on x-ray, an MRI is the next test of choice. If an MRI is not available or the patient can not be placed into the scanner a CT may be used as a substitute. MRI sensitivity for radiographically occult fracture is greater than CT. Bone scan is another useful alternative however substantial drawbacks include decreased sensitivity, early false negative results, and decreased conspicuity of findings due to age related metabolic changes in the elderly.

As the patients most often require an operation, full pre-operative general investigation is required. This would normally include blood tests, ECG and chest x-ray.

X-rays of the hip may suggest and/or verify the diagnosis. X-rays usually demonstrate a flattened, and later fragmented, femoral head. A bone scan or MRI may be useful in making the diagnosis in those cases where X-rays are inconclusive. Usually, plain radiographic changes are delayed 6 weeks or more from clinical onset, so bone scintigraphy and MRI are done for early diagnosis. MRI results are more accurate, i.e. 97 to 99% against 88 to 93% in plain radiography. If MRI or bone scans are necessary, a positive diagnosis relies upon patchy areas of vascularity to the capital femoral epiphysis (the developing femoral head).

Bone lesions in multiple myeloma patients may be treated with low-dose radiation therapy in order to reduce pain and other symptoms. Used in combination with immunochemotherapy, radiation therapy can be used to treat certain cancers when aimed at areas of bone lesion and softened bone.

Biophosphonates are drugs that are used to prevent bone mass loss and are often used to treat osteolytic lesions. Zoledronic acid (Reclast) is a specific drug given to cancer patients to prevent the worsening of bone lesions and has been reported to have anti-tumor effects as well. Zoledronic acid has been clinically tested in conjunction with calcium and vitamin D to encourage bone health. Denosumab, a monoclonal antibody treatment RANKl inhibitor that targets the osteocyte apoptosis regualtory RANKL gene, is also prescribed to prevent bone metastases and bone lesions. Most biophosphonates are co-prescribed with disease-specific treatments, such as chemotherapy or radiation for cancer patients.

Microscopically, an astrocytoma is a mass that looks well-circumscribed and has a large cyst. The neoplasm may also be solid.

Under the microscope, the tumor is seen to be composed of bipolar cells with long "hairlike" GFAP-positive processes, giving the designation "pilocytic" (that is, made up of cells that look like fibers when viewed under a microscope). Some pilocytic astrocytomas may be more fibrillary and dense in composition. There is often presence of Rosenthal fibers, eosinophilic granular bodies and microcysts. Myxoid foci and oligodendroglioma-like cells may also be present, though non-specific. Long-standing lesions may show hemosiderin-laden macrophages and calcifications.

X-rays of the affected hip usually make the diagnosis obvious; AP (anteroposterior) and lateral views should be obtained.

Trochanteric fractures are subdivided into either intertrochanteric (between the greater and lesser trochanter) or pertrochanteric (through the trochanters) by the Müller AO Classification of fractures. Practically, the difference between these types is minor. The terms are often used synonymously. An "isolated trochanteric fracture" involves one of the trochanters without going through the anatomical axis of the femur, and may occur in young individuals due to forceful muscle contraction. Yet, an "isolated trochanteric fracture" may not be regarded as a true hip fracture because it is not cross-sectional.

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.

On CT scans, bone cysts that have a radiodensity of 20 Hounsfield units (HU) or less, and are osteolytic, tend to be aneurysmal bone cysts.

In contrast, intraosseous lipomas have a lower radiodensity of -40 to -60 HU.

Simple (Unicameral) Bone Cyst

Some unicameral bone cysts may spontaneously resolve without medical intervention. Specific treatments are determined based on size of the cyst, strength of the bone, medical history, extent of the disease, activity level, symptoms an individual is experiencing, and tolerance for specific medications, procedures, or therapies. The types of methods used to treat this type of cyst are curettage and bone grafting, aspiration, steroid injections, and bone marrow injections. Watchful waiting and activity modifications are the most common nonsurgical treatments that will help resolve and help prevent unicameral bone cysts from occurring and reoccurring.

Aneurysmal Bone Cyst

The aneurysmal bone cyst can be treated with a variety of different methods. These methods include open curettage and bone grafting with or without adjuvant therapy, cryotheraphy, sclerotherapy, ethibloc injections, radionuclide ablation, and selective arterial embolization. En-block resection and reconstruction with strut grafting are the most common treatments and procedures that prevent recurrences of this type of cyst.

Traumatic Bone Cyst

The traumatic bone cyst treatment consists of surgical exploration, curettage of the osseous socket and bony walls, subsequent filling with blood, and intralesional steroid injections. Young athletes can reduce their risk of traumatic bone cyst by wearing protective mouth wear or protective head gear.

In the early stages, bone scintigraphy and MRI are the preferred diagnostic tools.

X-ray images of avascular necrosis in the early stages usually appear normal. In later stages it appears relatively more radio-opaque due to the nearby living bone becoming resorbed secondary to reactive hyperemia. The necrotic bone itself does not show increased radiographic opacity, as dead bone cannot undergo bone resorption which is carried out by living osteoclasts. Late radiographic signs also include a radiolucency area following the collapse of subchondral bone (crescent sign) and ringed regions of radiodensity resulting from saponification and calcification of marrow fat following medullary infarcts.

A variety of methods may be used to treat the most common being the total hip replacement (THR). However, THRs have a number of downsides including long recovery times and short life spans (of the hip joints). THRs are an effective means of treatment in the older population; however, in younger people they may wear out before the end of a person's life.

Other technicques such as metal on metal resurfacing may not be suitable in all cases of avascular necrosis; its suitability depends on how much damage has occurred to the femoral head. Bisphosphonates which reduces the rate of bone breakdown may prevent collapse (specifically of the hip) due to AVN.