Imaging studies such as X-rays, computed tomography scans, or MRI may be required to diagnose clear-cell sarcoma together with a physical exam. Normally a biopsy is also necessary. Furthermore, a chest CT, a bone scan and positron emission tomography (PET) may be part of the tests in order to evaluate areas where metastases occur.

Giant-cell lung cancers have long been considered to be exceptionally aggressive malignancies that grow very rapidly and have a very poor prognosis.

Many small series have suggested that the prognosis of lung tumors with giant cells is worse than that of most other forms of non-small-cell lung cancer (NSCLC), including squamous cell carcinoma, and spindle cell carcinoma.

The overall five-year survival rate in GCCL varies between studies but is generally considered to be very low. The (US) Armed Forces Institute of Pathology has reported a figure of 10%, and in a study examining over 150,000 lung cancer cases, a figure of 11.8% was given. However, in the latter report the 11.8% figure was based on data that included spindle cell carcinoma, a variant which is generally considered to have a less dismal prognosis than GCCL. Therefore, the likely survival of "pure" GCCL is probably lower than the stated figure.

In the large 1995 database review by Travis and colleagues, giant-cell carcinoma has the third-worst prognosis among 18 histological forms of lung cancer. (Only small-cell carcinoma and large-cell carcinoma had shorter average survival.)

Most GCCL have already grown and invaded locally and/or regionally, and/or have already metastasized distantly, and are inoperable, at the time of diagnosis.

Because of its rarity, there have been no randomized clinical trials of treatment of GCCL, and all information available derives from small retrospective institutional series or multicenter metadata.

On X-ray, giant-cell tumors (GCTs) are lytic/lucent lesions that have an epiphyseal location and grow to the articular surface of the involved bone. Radiologically the tumors may show characteristic 'soap bubble' appearance. They are distinguishable from other bony tumors in that GCTs usually have a nonsclerotic and sharply defined border. About 5% of giant-cell tumors metastasize, usually to a lung, which may be benign metastasis, when the diagnosis of giant-cell tumor is suspected, a chest X-ray or computed tomography may be needed. MRI can be used to assess intramedullary and soft tissue extension.

The diagnosis of giant-cell tumors is based on biopsy findings. The key histomorphologic feature is, as the name of the entity suggests, (multinucleated) giant cells with up to a hundred nuclei that have prominent nucleoli. Surrounding mononuclear and small multinucleated cells have nuclei similar to those in the giant cells; this distinguishes the lesion from other osteogenic lesions which commonly have (benign) osteoclast-type giant cells. Soap-bubble appearance is a characteristic feature.

While cancer is generally considered a disease of old age, children can also develop cancer. In contrast to adults, carcinomas are exceptionally rare in children..

The two biggest risk factors for ovarian carcinoma are age and family history.

Staging of carcinoma refers to the process of combining physical/clinical examination, pathological review of cells and tissues, surgical techniques, laboratory tests, and imaging studies in a logical fashion to obtain information about the size of the neoplasm and the extent of its invasion and metastasis.

Carcinomas are usually staged with Roman numerals. In most classifications, Stage I and Stage II carcinomas are confirmed when the tumor has been found to be small and/or to have spread to local structures only. Stage III carcinomas typically have been found to have spread to regional lymph nodes, tissues, and/or organ structures, while Stage IV tumors have already metastasized through the blood to distant sites, tissues, or organs.

In some types of carcinomas, Stage 0 carcinoma has been used to describe carcinoma "in situ", and occult carcinomas detectable only via examination of sputum for malignant cells (in lung carcinomas).

In more recent staging systems, substages (a, b, c) are becoming more commonly used to better define groups of patients with similar prognosis or treatment options.

Carcinoma stage is the variable that has been most consistently and tightly linked to the prognosis of the malignancy.

The criteria for staging can differ dramatically based upon the organ system in which the tumor arises. For example, the colon and bladder cancer staging system relies on depth of invasion, staging of breast carcinoma is more dependent on the size of the tumor, and in renal carcinoma, staging is based on both the size of the tumor and the depth of the tumor invasion into the renal sinus. Carcinoma of the lung has a more complicated staging system, taking into account a number of size and anatomic variables.

The UICC/AJCC TNM systems are most often used. For some common tumors, however, classical staging methods (such as the Dukes classification for colon cancer) are still used.

Radiologically

- Odontogenic Myxoma

- Ameloblastoma

- Central Giant Cell Granuloma

- Adenomatoid odontogenic tumor

Histologically

- Orthokeratocyst

- Radicular cyst (particularly if the OKC is very inflamed)

- Unicystic ameloblastoma

Treatment depends upon the site and the extent of the disease. Clear cell sarcoma is usually treated with surgery in the first place in order to remove the tumor. The surgical procedure is then followed by radiation and sometimes chemotherapy. Few cases of clear cell sarcoma respond to chemotherapy. Several types of targeted therapy that may be of benefit to clear cell sarcoma patients are currently under investigation.

Fibrosarcoma occurs most frequently in the mouth in dogs . The tumor is locally invasive, and often recurs following surgery . Radiation therapy and chemotherapy are also used in treatment. Fibrosarcoma is also a rare bone tumor in dogs.

In cats, fibrosarcoma occurs on the skin. It is also the most common vaccine-associated sarcoma. In 2014, Merial launched Oncept IL-2 in Europe for the management of such feline fibrosarcomas.

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).

The definitive diagnosis is by histologic analysis, i.e. and examination under the microscope.

Under the microscope, OKCs vaguely resemble keratinized squamous epithelium; however, they lack rete ridges and often have an artifactual separation from their basement membrane.

On a CT scan, The radiodensity of a keratocystic odontogenic tumour is about 30 Hounsfield units, which is about the same as ameloblastomas. Yet, ameloblastomas show more bone expansion and seldom show high density areas.

Ancillary testing for fibrosarcoma includes IHC, where vimentin is positive, cytokeratin and S100 are negative, and actin is variable.

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.

Keratoacanthoma presents as a fleshy, elevated and nodular lesion with an irregular crater shape and a characteristic central hyperkeratotic core. Usually the patient will notice a rapidly growing dome-shaped tumor on sun-exposed skin.

If the entire lesion is removed, the pathologist will probably be able to differentiate between keratoacanthoma and squamous cell carcinoma. If only part of the lesion is removed, confident diagnosis may be impossible.

Diagnosis is made by imaging with a contrast-enhanced MRI or CT scan of the brain.

It is recommended that children with TSC be screened for SEGA with neuroimaging every 1–3 years.

The treatment for CGCG is thorough curettage. A referral is made to an oral surgeon. Recurrence ranges from 15%–20%. In aggressive tumors, three alternatives to surgery are undergoing investigation:

- corticosteroids;

- calcitonin (salmon calcitonin);

- interferon α-2a.

These therapeutic approaches provide positive possible alternatives for large lesions. The long term prognosis of giant-cell granulomas is good and metastases do not develop.

The majority of patients with neurocutaneous melanosis are asymptomatic and therefore have a good prognosis with few complications. Most are not diagnosed, so definitive data in not available. For symptomatic patients, the prognosis is far worse. In patients without the presence of melanoma, more than 50% die within 3 years of displaying symptoms. While those with malignancy have a mortality rate of 77% with most patients displaying symptoms before the age of 2.

The presence of a Dandy-Walker malformation along with neurocutaneous melanosis, as occurs in 10% of symptomatic patients, further deteriorates prognosis. The median survival time for these patients is 6.5 months after becoming symptomatic.

If a patient displays congenital melanocytic nevi or giant congenital melanocytic nevi, the criteria for diagnosis of neurocutaneous melanosis is as follows:

- Melanocytic deposits exist within the central nervous system that are either malignant or benign

- The cutaneous lesions, giant or otherwise, are not malignant

This criteria is typically validated through biopsy of the cutaneous lesions and imaging of the central nervous system. It is important to establish that the cutaneous lesions are benign. If not, then the melanocytic deposits in the central nervous system may be the result of metastasis of cutaneous melanoma and not neurocutaneous melanosis.

Imaging has been shown to be the only reliable detection method for the presence of neurocutaneous melanosis that can be performed in living patients. Currently, the preferred imaging modality for diagnosis of neurocutaneous melanosis is Magnetic Resonance Imaging, although ultrasound is another viable option. The signal due melanin deposits in the leptomeninges typical of neurocutaneous melanosis can be easily detected in MRI scans of patients under four months old. In patients above this age, there is some suggestion that normal brain myelination may partially obscure these signals.

As most patients with neurocutaneous melanosis are asymptomatic, those who are diagnosed through MR imaging are not guarantied to develop symptoms. Those diagnosed who did not develop symptoms ranged from 10% to 68%. This wide range is most likely due to the large number of asymptomatic, undiagnosed patients with neurocutaneous melanosis.

In most series, LCLC's comprise between 5% and 10% of all lung cancers.

According to the Nurses' Health Study, the risk of large cell lung carcinoma increases with a previous history of tobacco smoking, with a previous smoking duration of 30 to 40 years giving a relative risk of approximately 2.3 compared to never-smokers, and a duration of more than 40 years giving a relative risk of approximately 3.6.

Another study concluded that cigarette smoking is the predominant cause of large cell lung cancer. It estimated that the odds ratio associated with smoking two or more packs/day for current smokers is 37.0 in men and 72.9 in women.

Excision of the entire lesion, with adequate margin, will remove the lesion, allow full tissue diagnosis, and leave a planned surgical wound which can usually be repaired with a good cosmetic result. However, removing the entire lesion (especially on the face) may present difficult problems of plastic reconstruction. (On the nose and face, Mohs surgery may allow for good margin control with minimal tissue removal, but many insurance companies require the definitive diagnosis of a malignancy "before" they are prepared to pay the extra costs of Mohs surgery.) Especially in more cosmetically-sensitive areas, and where the clinical diagnosis is reasonably certain, alternatives to surgery may include no treatment (awaiting spontaneous resolution).

On the trunk, arms, and legs, electrodesiccation and curettage often suffice to control keratoacanthomas until they regress. Other modalities of treatment include cryosurgery and radiotherapy; intralesional injection of methotrexate or of 5-fluorouracil have also been used.

Recurrence after electrodesiccation and curettage can occur; it can usually be identified and treated promptly with either further curettage or surgical excision.

Histological variants of lung cancer classified as sarcomatoid carcinoma include pleomorphic carcinoma, giant cell carcinoma, spindle cell carcinoma, carcinosarcoma, and pulmonary blastoma.

Sarcomatoid carcinoma is a relatively uncommon form of cancer whose malignant cells have histological, cytological, or molecular properties of both epithelial tumors ("carcinoma") and mesenchymal tumors ("sarcoma").

LCC is, in effect, a "diagnosis of exclusion", in that the tumor cells lack light microscopic characteristics that would classify the neoplasm as a small-cell carcinoma, squamous-cell carcinoma, adenocarcinoma, or other more specific histologic type of lung cancer.

LCC is differentiated from small-cell lung carcinoma (SCLC) primarily by the larger size of the anaplastic cells, a higher cytoplasmic-to-nuclear size ratio, and a lack of "salt-and-pepper" chromatin.