For SPB the most common presenting symptom is that of pain in the affected bone. Back pain and other consequences of the bone lesion may occur such as spinal cord compression or pathological fracture. Around 85% of extramedullary plasmacytoma presents within the upper respiratory tract mucosa, causing possible symptoms such as epistaxis, rhinorrhoea and nasal obstruction. In some tissues it may be found as a palpable mass.

Plasmacytoma is a plasma cell dyscrasia in which a plasma cell tumour grows within soft tissue or within the axial skeleton.

The International Myeloma Working Group lists three types: solitary plasmacytoma of bone (SPB); extramedullary plasmacytoma (EP), and multiple plasmacytomas that are either primary or recurrent. The most common of these is SPB, accounting for 3–5% of all plasma cell malignancies. SPBs occur as lytic lesions within the axial skeleton and extramedullary plasmacytomas most often occur in the upper respiratory tract (85%), but can occur in any soft tissue. Approximately half of all cases produce paraproteinemia. SPBs and extramedullary plasmacytomas are mostly treated with radiotherapy, but surgery is used in some cases of extramedullary plasmacytoma. The skeletal forms frequently progress to multiple myeloma over the course of 2–4 years.

Due to their cellular similarity, plasmacytomas have to be differentiated from multiple myeloma. For SPB and extramedullary plasmacytoma the distinction is the presence of only one lesion (either in bone or soft tissue), normal bone marrow (<5% plasma cells), normal skeletal survey, absent or low paraprotein and no end organ damage.

Gigantiform cementoma is a rare, autosomal dental tumor. It is benign, but without intervention it can result in severe disfigurement of the jaw. The cause of this tumor is currently unknown. This is an exceedingly rare tumor with only a handful of documented cases worldwide. The most famous case is of Novemthree Siahaan (who died on September 15, 2005), a young Indonesian boy from Batam Island who received medical care in Haulien, Taiwan through a Buddhist missionary from the Tzu Chi Foundation, which was documented on the Discovery Health Channel. Another famous case is a young Korean girl named Ayun Lee (August 26, 2003~) and her father Young-hak Lee whose case has shown that the tumor can be heritable. She is currently under treatment, which she may need to continue until her growth stops in her early 20s.

The term has been used in the past to describe florid cemento-osseous dysplasia, but it is now reserved for an autosomal dominant condition affecting the maxillae. It affects mostly Caucasian people under the age of 10. Treatment is difficult. Surgical removal of the affected bone is needed, and has to be followed by reconstruction.

An otic polyp (also called aural polyp) is a benign proliferation of chronic inflammatory cells associated with granulation tissue, in response to a longstanding inflammatory process of the middle ear.

Patients usually present with otorrhea, conductive hearing loss, and otalgia, while bleeding and a sensation of a mass are much less common.

A bone cyst or geode is a cyst that forms in bone.

Types include:

- Unicameral bone cyst

- Aneurysmal bone cyst

- Traumatic bone cyst

Cemento-osseous dysplasia (COD) is a benign condition of the jaws that may arise from the fibroblasts of the periodontal ligaments. It is most common in African-American females. The three types are periapical cemental dysplasia (common in those of African descent), focal cemento-osseous dysplasia (Caucasians), and florid cemento-osseous dysplasia (African descent). Periapical occurs most commonly in the mandibular anterior teeth while focal appears predominantly in the mandibular posterior teeth and florid in both maxilla and mandible in multiple quadrants.

Ectopic calcification is a pathologic deposition of calcium salts in tissues or bone growth in soft tissues. This can be a symptom of hyperphosphatemia. Formation of osseous tissue in soft tissues such as the lungs, eyes, arteries, or other organs is known as ectopic calcification, dystrophic calcification, or ectopic ossification.

Ectopic ossification of the heart valves is an indicator of future heart problems, hyperparathyroidism, and necrosis of tissues.

Progressive osseous heteroplasia is a cutaneous condition characterized by cutaneous or subcutaneous ossification.

According to the Progressive Osseous Heteroplasia Association:

It is associated with "GNAS".

There is no treatment necessary for any type of COD. Diagnosis is important so that the treating doctor does not confuse it for another periapical disease such as rarefying osteitis or condensing osteitis. Incorrect diagnosis could lead to unnecessary root canal treatments. It can be diagnosed by radiographic appearance. Confirming the tooth is vital, as is noting the demographic (African American females).

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.

Warty dyskeratoma must be differentiated from vulvar dysplasia, Bowenoid papulosis, squamous carcinoma, condyloma, and other viral-induced squamous lesions.

Warty dyskeratoma, also known as an Isolated dyskeratosis follicularis, is a benign epidermal proliferation with distinctive histologic findings that may mimic invasive squamous cell carcinoma and commonly manifests as an umbilicated (Having a central mark or depression resembling a navel) lesion with a keratotic plug, WD have some histopathologic similarities to viral warts but it's not caused by HPV and the majority of these lesions display overall histopathologic features consistent with a follicular adnexal neoplasm. usually limited to the head, neck, scalp or face and vulva. Lesions are generally and sporadic and may be associated with a follicular unit. Oral involvement, particularly the hard palate, and genital involvement have been reported. it can also be thought of as one of the manifestations of focal acantholytic dyskeratosis, an epidermal reaction pattern that can be seen in several disorders, including Darier's disease and Grover's disease. But the main Difference between Darier disease and Warty dyskeratoma, is that Darier disease inherited dermatosis (autosomal dominant) consisting of multiple keratotic papules on the face, trunk, and extremities, while WD occurs as an isolated, noninherited, single keratotic nodule mainly confined to the head and neck as mentioned earlier.

Because many organs can be affected by myeloma, the symptoms and signs vary greatly. A mnemonic sometimes used to remember some of the common symptoms of multiple myeloma is CRAB: C = calcium (elevated), R = renal failure, A = anemia, B = bone lesions. Myeloma has many other possible symptoms, including opportunistic infections (e.g., pneumonia) and weight loss. CRAB symptoms and proliferation of monoclonal plasma cells in the bone marrow are part of the diagnostic criteria of multiple myeloma.

This disorder is rare, and is characterised by an asymmetrical limb deformity due to localized overgrowth of cartilage, histologically resembling osteochondroma. It is believed to affect the limb bud in early fetal life. The condition occurs mostly in the ankle or knee region and it is always confined to a single limb. This usually involves only the lower extremities and on medial side of the epiphysis. It is named after researcher David Trevor.

In traumatic heterotopic ossification (traumatic myositis ossificans), the patient may complain of a warm, tender, firm swelling in a muscle and decreased range of motion in the joint served by the muscle involved. There is often a history of a blow or other trauma to the area a few weeks to a few months earlier. Patients with traumatic neurological injuries, severe neurologic disorders or severe burns who develop heterotopic ossification experience limitation of motion in the areas affected.

Terminal osseous dysplasia with pigmentary defects is a cutaneous condition characterized by hyperpigmented, atrophic facial macules.

It has been associated with "FLNA".

Bone pain affects almost 70% of patients and is the most common symptom. Myeloma bone pain usually involves the spine and ribs, and worsens with activity. Persistent localized pain may indicate a pathological bone fracture. Involvement of the vertebrae may lead to spinal cord compression or kyphosis. Myeloma bone disease is due to the overexpression of receptor activator for nuclear factor κ B ligand (RANKL) by bone marrow stroma. RANKL activates osteoclasts, which resorb bone. The resultant bone lesions are lytic (cause breakdown) in nature, and are best seen in plain radiographs, which may show "punched-out" resorptive lesions (including the "raindrop" appearance of the skull on radiography). The breakdown of bone also leads to the release of calcium into the blood, leading to hypercalcemia and its associated symptoms.

Trevor disease, also known as Fairbank's disease and Trevor's disease, is a congenital bone developmental disorder. There is 1 case per million population. The condition is three times more common in males than in females.

Heterotopic ossification (HO) is the process by which bone tissue forms outside of the skeleton.

Diagnosis is mostly based on general examination and radiographs, and it should be taken when abnormality of the teeth is suspected as most of the affected teeth have normal clinical appearance.

Differential diagnosis is very important to have a definitive diagnosis as some radiographic or histologic features of dentine dysplasia may bear a resemblance to different disorders:

- Dentinogenesis Imperfecta

- Odontodysplasia

- Calcinosis

- Osteogenesis imperfecta

- Ehlers Danlos syndrome

- Goldblatt syndrome

- Schimke immuno-osseous dysplasia

- Brachio-skeleto-genital syndrome.

Fibrous ankylosis is a fibrous connective tissue process which results in decreased range of motion. Symptoms present as bony ankylosis, in which osseous tissue fuses two bones together reducing mobility, which is why fibrous ankylosis is also known as false ankylosis.

Pathology may be the result of trauma, disease, chronic inflammation, or surgery.

Some research suggests fibrous ankylosis may precede the development of bony ankylosis

A Salter–Harris fracture is a fracture that involves the epiphyseal plate or growth plate of a bone. It is a common injury found in children, occurring in 15% of childhood long bone fractures.

Causes of paraproteinemia include the following:

- Leukemias and lymphomas of various types, but usually B-cell Non-Hodgkin lymphomas with a plasma cell component.

- Myeloma

- Plasmacytoma

- Lymphoplasmacytic lymphoma

- Idiopathic (no discernible cause): some of these will be revealed as leukemias or lymphomas over the years.

- Monoclonal gammopathy of undetermined significance

- Primary AL amyloidosis (light chains only)