Villonodular synovitis is a type of synovial swelling.

Types include:

- Pigmented villonodular synovitis (PVNS)

- Giant cell tumor of the tendon sheath (GCTS)

Though they have very different names, they have the same histology, and stain positive for CD68, HAM56, and vimentin.

They are sometimes discussed together.

Giant-cell tumor of the tendon sheath, also known as giant-cell synovioma and localized nodular tenosynovitis, is a firm lesion, measuring 1 to 3 cm in diameter, and is most commonly attached to the tendons of the fingers, hands, and wrists, with a predilection for the flexor surfaces. Giant-cell tumor of tendon sheaths most often affect the wrist and fingers of males and females from the ages of 20-50 . These tumors are typically painless and can cause cortical erosion. Surgery to remove the tumor is a common treatment, though the tumors tend to recur.

The most common symptom is mild to severe pain that is gradually progressive in the affected region and may be initially attributed to a minor injury or sports-related injury. Pain may be present for several weeks, months, or years. Other symptoms in order of most common to least commonly observed include swelling, a limp (when affected bone is in the lower extremity), joint stiffness, and a soft tissue mass.

Physical findings include localized tenderness and a decreased range of motion in the involved bone and nearby joint, muscle atrophy, a palpable mass, soft tissue swelling, and joint effusion in the affected area. Less commonly, pathological fractures can be found, especially in cases involving the foot. In cases involving the temporal bone, tinnitus, dizziness, and hearing loss have been reported.

In a publication by Turcotte et al. it was found that the average duration of symptoms for patients with chondroblastoma was about 20 months, ranging from 5 weeks to 16 years.

Typically patients present with progressive pain, often long standing and/or bony swelling and restricted range of movement in affected limb 3,12. The latter is most often the case in bones with little overlying soft tissues (e.g. short tubular bones of the hands and feet).

Most chondromyxoid fibromas are located in the metaphyseal region of long bones (60%), and may extend to the epiphyseal line and even rarely abut the articular surface 3,12. They are almost never just epiphyseal 3. The classical site is the upper 1/3rd of tibia ( which accounts for 25% of all cases) with the small tubular bones of the foot, the distal femur and pelvis being other relatively common locations 12.

Rarely occur in the skull or skull base.

Giant-cell fibroma is a type of fibroma not associated with trauma or irritation. It can occur at any age and on a mucous membrane surface. The most common oral locations are on the gingiva of the mandible, tongue, and palate. It is a localized reactive proliferation of fibrous connective tissue.

Giant-cell fibroma (GCF) is a benign non-neoplastic lesion first described by Weathers and Callihan (1974). It occurs in the first three decades of life and predominates in females (Houston, 1982; Bakos, 1992). Clinically, the GCF presents as an asymptomatic, papillary and pedunculated lesion. The most predominant location is the mandibular gingiva (Houston, 1982; Bakos, 1992). Histologically, the GCF is distinctive, consisting of fibrous connective tissue without inflammation and covered with stratified squamous hyperplastic epithelium. The most characteristic histological feature is the presence of large spindle-shaped and stellate-shaped mononuclear cells and multinucleated cells. These cells occur in a variety of lesions, such as the fibrous papule of the nose, ungual fibroma, acral fibrokeratoma, acral angiofibroma and desmoplastic fibroblastoma (Swan, 1988; Pitt et al., 1993; Karabela-Bouropoulou et al., 1999; Jang et al., 1999).

Despite many studies, the nature of the stellated multinucleate and mononuclear cell is not clear (Weathers and Campbell, 1974; Regezi et al., 1987; Odell et al., 1994; Magnusson and Rasmusson, 1995).

CGCG lesions are found more commonly in the anterior of the maxilla and the mandible in younger people (before age 20). They are characterized by large lesions that expand the cortical plate and can resorb roots and move teeth. They are composed of multi-nucleated giant cells. CGCG has a slight predilection for females.

Radiographically :

It appears as multilocular radiolucencies of bone.The margin of the lesion has scalloped appearance and is well demarcated. Resorption and divergence of roots is also seen.

There are two types of CGCG's, non-aggressive and aggressive. The former has a slow rate of growth and thus less likely to resorb roots and perforate the cortical plate. The aggressive form has rapid growth and thus is much more likely to resorb roots and perforate the cortical plate. It also has a high rate for recurrence and can be painful and cause paresthesia.

Differential diagnosis to include: odontogenic keratocyst (OKC), ameloblastoma, odontogenic myxoma, hemangioma, central odontogenic fibroma, hyperparathyroid tumor, and cherubism.

Central giant-cell granuloma (CGCG) is a benign condition of the jaws. It is twice as likely to affect women and is more likely to occur in 20- to 40-year-old people. Central giant-cell granulomas are more common in the mandible and often cross the midline.

It is more common in women than in men by a ratio of 2:1 and more common in those of Northern European descent, as well as those residing at higher (northern/southern) latitudes. The mean age of onset is >55 years, and it is rare in those younger than 55 years of age.

People present with:

- bruits

- fever

- headache

- tenderness and sensitivity on the scalp

- jaw claudication (pain in jaw when chewing)

- tongue claudication (pain in tongue when chewing) and necrosis

- reduced visual acuity (blurred vision)

- acute visual loss (sudden blindness)

- diplopia (double vision)

- acute tinnitus (ringing in the ears)

- polymyalgia rheumatica (in 50%)

The inflammation may affect blood supply to the eye; blurred vision or sudden blindness may occur. In 76% of cases involving the eye, the ophthalmic artery is involved causing arteritic anterior ischemic optic neuropathy.

Giant-cell arteritis may present with atypical or overlapping features. Early and accurate diagnosis is important to prevent ischemic vision loss. Therefore, this condition is considered a medical emergency.

Peripheral giant-cell granuloma (PGCG) is an oral pathologic condition that appears in the mouth as an overgrowth of tissue due to irritation or trauma. Because of its overwhelming incidence on the gingiva, the condition is associated with two other diseases, though not because they occur together. Instead, the three are associated with each other because they appear frequently on gingiva: pyogenic granuloma and peripheral ossifying fibroma. Because of its similar microscopic appearance to the bony lesions called central giant-cell granulomas, peripheral giant-cell granulomas are considered by some researchers to be a soft tissue equivalent.

The appearance of peripheral giant-cell granulomas is similar to pyogenic granulomas. The color ranges from red to bluish-purple, but is usually more blue in comparison to pyogenic granulomas. It can be sessile or pedunculated with the size usually being less than 2 cm.

There is a gender difference with 60% of the disease occurring in females. The prevalence of peripheral giant-cell granulomas is highest around 50 - 60 years of age. It appears only on the gingiva or on an edentulous (without teeth) alveolar ridge. It is more often found in the mandible rather than the maxilla but can be found in either anterior or posterior areas. The underlying alveolar bone can be destroyed, leaving a unique appearance referred to as "cupping resorption" or "saucerization".

Peripheral giant-cell granulomas appear microscopically as a large number of multinucleated giant cells, which can have up to dozens of nuclei. Additionally, there are mesenchymal cells that are ovoid and spindle-shaped. Near the borders of the lesion, deposits of hemosiderin and hemorrhage is often found. In 50% of cases, ulcerations are present.

The afflicted may have relatively small amounts of pain that will quickly increase in severity over a time period of 6–12 weeks. The skin temperature around the bone may increase, a bony swelling may be evident, and movement may be restricted in adjacent joints.

Spinal lesions may cause quadriplegia and patients with skull lesions may have headaches.

PCNA and Ki67 immunoreactivity happens in case of fibroma and peripheral granuloma.

The color of peripheral ossifying fibromas ranges from red to pink, and is frequently ulcerated. It can be sessile or pedunculated with the size usually being less than 2 cm. Weeks or months may pass by before it is seen and diagnosed.

There is a gender difference with 66% of the disease occurring in females. The prevalence of peripheral ossifying fibromas is highest around 10 – 19 years of age. It appears only on the gingiva, more often on the maxilla rather than the mandible, and is frequently found in the area around incisors and canines. The adjacent teeth are usually not affected.

Peripheral ossifying fibromas appear microscopically as a combination of a mineralized product and fibrous proliferation. The mineralized portion may be bone, cementum-like, or dystrophic calcifications. Additionally, highly developed bone or cementum is more likely to be present when the peripheral ossifying fibroma has existed for a longer period of time.

The majority of cases occur in the second and third decades, with approximately 75% of cases occurring before the age of 30 years 1,12-15. There is no recognised gender predilection. Examples have however been seen in patients up to the age of 75 years. In some series there is a male predilection 12 whilst in others no such distribution is found 2

Brown tumours consist of fibrous tissue, woven bone and supporting vasculature, but no matrix. The osteoclasts consume the trabecular bone that osteoblasts lay down and this front of reparative bone deposition followed by additional resorption can expand beyond the usual shape of the bone, involving the periosteum thus causing bone pain. The characteristic brown coloration results from hemosiderin deposition into the osteolytic cysts. Hemosiderin deposition is not a distinctive feature of brown tumors; it may also be seen in giant cell tumors of the bone.

Brown tumors may be rarely associated with ectopic parathyroid adenomas or end stage renal osteodystrophy.

Peripheral ossifying fibroma “a gingival nodule which is composed of a cellular fibroblastic connective tissue stroma which is associated with the formation of randomly dispersed foci of mineralised products, which consists of bone, cementum-like tissue, or a dystrophic calcification. The lesion is considered part of an ossifying fibroma, but that is usually considered to be a gnathic tumor. Because of its overwhelming incidence on the gingiva, the condition is associated with two other diseases, though not because they occur together. Instead, the three are associated with each other because they appear frequently on gingiva: pyogenic granuloma and peripheral giant cell granuloma. Some researchers believe peripheral ossifying fibromas to be related to pyogenic fibromas and, in some instances, are the result of a pyogenic granuloma which has undergone fibrosis and calcification.

The term "peripheral ossifying fibroma" has been criticized as this lesion is not related to the ossifying fibroma of bone and is not a fibroma. This term is used in America, however in Britain, this lesion would be termed a fibrous epulis containing bone.

Chondroblastoma is a rare, benign, locally aggressive bone tumor that typically affects the epiphyses or apophyses of long bones. It is thought to arise from an outgrowth of immature cartilage cells (chondroblasts) from secondary ossification centers, originating from the epiphyseal plate or some remnant of it.

Chondroblastoma is very uncommon, accounting for only 1-2% of all bone tumors. It affects mostly children and young adults with most patients being in the second decade of life, or less than 20 years of age. Chondroblastoma shows a predilection towards the male sex, with a ratio of male to female patients of 2:1. The most commonly affected site is the femur, followed by the humerus and tibia. Less commonly affected sites include the talus and calcaneus of the foot and flat bones.

Swelling is the most common presenting complaint; however, OKCs may be asymptomatic and found incidentally on dental X-rays.

Commonly affected sites are metaphyses of vertebra, flat bones, femur and tibia. Approximate percentages by sites are as shown:

- Skull and mandible (4%)

- Spine (16%)

- Clavicle and ribs (5%)

- Upper extremity (21%)

- Pelvis and sacrum (12%)

- Femur (13%)

- Lower leg (24%)

- Foot (3%)

Malignant transformation to squamous cell carcinoma may occur, but is unusual.

The lesion is usually painless. The usual appearance is of two excess tissue folds in alveolar vestibule/buccal sulcus, with the flange of the denture fitting in between the two folds. It may occur in either the maxillary or mandibular sulci, although the latter is more usual. Anterior locations are more common than posterior. Less commonly there may be a single fold, and the lesion may appear on the lingual surface of the mandibular alveolar ridge.

The swelling is firm and fibrous, with a smooth, pink surface. The surface may also show ulceration or erythema. The size of the lesion varies from less than 1 cm to involving the entire length of the sulcus.

Epulis (literally, 'on the gingiva') is a general term for any gingival or alveolar tumor (i.e. lump on the gum). This term describes only the location of a lump and has no implication on the histologic appearance of a lesion. "Epulis" is also sometimes used synonymously with epulis fissuratum, however other conditions are classified as epulides, e.g. giant cell epulis (peripheral giant cell granuloma), ossifying fibroid epulis (peripheral ossifying fibroma), and congenital epulis.

This type of epulis is neither pyogenic ("pus producing") nor a true granuloma, but it is a vascular lesion. About 75% of all pyogenic granulomas occur on the gingiva, although they may also occur elsewhere in the mouth or other parts of the body (where the term epulis is inappropriate). This common oral lesion is thought to be a reaction to irritation of the tissues and poor oral hygiene. It is more common in younger people and in females, and appears as a red-purple swelling and bleeds easily.

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.

Giant-cell arteritis (GCA), also called temporal arteritis, is an inflammatory disease of blood vessels. Symptoms may include headache, pain over the temples, flu-like symptoms, double vision, and difficulty opening the mouth. Complication can include blockage of the artery to the eye with resulting blindness, aortic dissection, and aortic aneurysm. GCA is frequently associated with polymyalgia rheumatica.

The cause is unknown. The underlying mechanism involves inflammation of the small blood vessels that occur within the walls of larger arteries. This mainly affects arteries around the head and neck, though some in the chest may also be affected. Diagnosis is suspected based on symptoms, blood tests, and medical imaging, and confirmed by biopsy of the temporal artery. However, in about 10% of people the temporal artery is normal.

Treatment is typically with high doses of steroids, such as prednisone. Once symptoms have resolved the dose is then decreased by about 15% per month. Once a low dose is reached, the taper is slowed further over the subsequent year. Other medications that may be recommended include bisphosphonates to prevent bone loss and a proton pump inhibitor to prevent stomach problems.

It affects about 1 in 15,000 people over the age of 50 a year. The condition typically only occurs in those over the age of 50 being most common among those in their 70s. Females are more often affected than males. Those of northern European descent are more commonly affected. Life expectancy is typically normal. The first description of the condition occurred in 1890.