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Deep Learning Technology: Sebastian Arnold, Betty van Aken, Paul Grundmann, Felix A. Gers and Alexander Löser. Learning Contextualized Document Representations for Healthcare Answer Retrieval. The Web Conference 2020 (WWW'20)
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The most conclusive test for a patient with a potential neurofibrosarcoma is a tumor biopsy (taking a sample of cells directly from the tumor itself). MRIs, X-rays, CT scans, and bone scans can aid in locating a tumor and/or possible metastasis.
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.
Tissue biopsy is the diagnostic modality of choice. Due to a high incidence of lymph node involvement, a sentinel lymph node biopsy is often performed. A common characteristic of epithelioid sarcoma (observed in 80% of all cases) is the loss of function of the SMARCB1 gene (also termed BAF47, INI1, or hSNF5). Immunohistochemical staining of INI1 is available and can be used for the diagnosis of epithelioid sarcoma. MRI is the diagnostic modality of choice for imaging prior to biopsy and pathologic diagnosis, with the primary role being the determination of anatomic boundaries.
The diagnosis of salivary gland tumors utilize both tissue sampling and radiographic studies. Tissue sampling procedures include fine needle aspiration (FNA) and core needle biopsy (bigger needle comparing to FNA). Both of these procedures can be done in an outpatient setting. Diagnostic imaging techniques for salivary gland tumors include ultrasound, computer tomography (CT) and magnetic resonance imaging (MRI).
Fine needle aspiration biopsy (FNA), operated in experienced hands, can determine whether the tumor is malignant in nature with sensitivity around 90%. FNA can also distinguish primary salivary tumor from metastatic disease.
Core needle biopsy can also be done in outpatient setting. It is more invasive but is more accurate compared to FNA with diagnostic accuracy greater than 97%. Furthermore, core needle biopsy allows more accurate histological typing of the tumor.
In terms of imaging studies, ultrasound can determine and characterize superficial parotid tumors. Certain types of salivary gland tumors have certain sonographic characteristics on ultrasound. Ultrasound is also frequently used to guide FNA or core needle biopsy.
CT allows direct, bilateral visualization of the salivary gland tumor and provides information about overall dimension and tissue invasion. CT is excellent for demonstrating bony invasion. MRI provides superior soft tissue delineation such as perineural invasion when compared to CT only.
The staging for epithelioid sarcoma takes into account size and location of the primary tumor, lymph node involvement, presence and location of metastasis, and histologic grade (a measure of disease aggressiveness)
Patient response to treatment will vary based on age, health, and the tolerance to medications and therapies.
Metastasis occurs in about 39% of patients, most commonly to the lung. Features associated with poor prognosis include a large primary tumor (over 5 cm across), high grade disease, co-existent neurofibromatosis, and the presence of metastases.
It is a rare tumor type, with a relatively poor prognosis in children.
In addition, MPNSTs are extremely threatening in NF1. In a 10-year institutional review for the treatment of chemotherapy for MPNST in NF1, which followed the cases of 1 per 2,500 in 3,300 live births, chemotherapy did not seem to reduce mortality, and its effectiveness should be questioned. Although with recent approaches with the molecular biology of MPNSTs, new therapies and prognostic factors are being examined.
The primary method for treatment is surgical, not medical. Radiation and chemotherapy are not needed for benign lesions and are not effective for malignant lesions.
Benign granular cell tumors have a recurrence rate of 2% to 8% when resection margins are deemed clear of tumor infiltration. When the resection margins of a benign granular cell tumor are positive for tumor infiltration the recurrence rate is increased to 20%. Malignant lesions are aggressive and difficult to eradicate with surgery and have a recurrence rate of 32%.
PECs typically stain for melanocytic markers (HMB-45, Melan A (Mart 1), Mitf) and myogenic markers (actin, myosin, calponin).
PECs bear significant histologic and immunohistochemical similarity to:
- angiomyolipoma,
- clear-cell sugar tumour (CCST),
- lymphangioleiomyomatosis, and,
- clear-cell myomelanocytic tumour of ligamentum teres/falciform ligament.
- abdominopelvic sarcoma of perivascular epitheloid cells
- primary extrapulmonary sugar tumour
Thus, it has been advocated that the above could be classified PEComas.
PEComas are rare and can have myriad features; therefore, they can be confused with carcinomas, smooth muscle tumours, adipocytic tumours, clear cell sarcomas, melanomas and gastrointestinal stromal tumours (GIST).
Criteria for CSF abnormalities:
- Increased opening pressure (> 200mm of H2O)
- Increased Leukocytes (>4/mm3)
- Elevated protein (>50 mg/dL)
- Decreased glucose (<60 mg/dL)
Tumor Markers:
- Carcinoembryonic antigin (CEA)
- alpha-fetoprotein
- beta-human chorionic gonadotropin
- carbohydrate antigen19-9
- creatine-kinase BB
- isoenzyme
- tissue polypeptide antigen
- beta2-microglobulin,
- beta-glucoronidase
- lactate dehydrogenase isoenzyme-5
- vascular endothelial growth factor
These markers can be good indirect indicator of NM but most are not sensitive enough to improve cytogical diagnosis.
Avoiding false-negative
- Draw CSF from symptomatic or radiographically demonstrated disease.
- Draw large amount of CSF (>10.5mL).
- Don't delay processing of specimen.
- Obtain at least 2 samples. The first sample has diagnostic sensitivity of 54% but with repeated sampling, diagnostic sensitivity is increased to 91%.
Ideal procedure for diagnosis:
Lumbar puntures --> cranial MRI --> spinal MRI --> radioisotope CSF flow --> ventricular or lateral cervical spine CSF analysis (if previous step yields no definitive answer)
The only reliable way to determine whether a soft-tissue tumour is benign or malignant is through a biopsy. There are two methods for acquisition of tumour tissue for cytopathological analysis;
- Needle Aspiration, via biopsy needle
- surgically, via an incision made into the tumour.
A pathologist examines the tissue under a microscope. If cancer is present, the pathologist can usually determine the type of cancer and its grade. Here, 'grade' refers to a scale used to represent concisely the predicted growth rate of the tumour and its tendency to spread, and this is determined by the degree to which the cancer cells appear abnormal when examined under a microscope. Low-grade sarcomas, although cancerous, are defined as those that are less likely to metastasise. High-grade sarcomas are defined as those more likely to spread to other parts of the body.
For soft-tissue sarcoma there are two histological grading systems : the National Cancer Institute (NCI) system and the French Federation of Cancer Centers Sarcoma Group (FNCLCC) system.
Soft tissue sarcomas commonly originate in the upper body, in the shoulder or upper chest. Some symptoms are uneven posture, pain in the trapezius muscle and cervical inflexibility [difficulty in turning the head].
The most common site to which soft tissue sarcoma spreads is the lungs.
There are three diagnostic criteria proposed:
1. the tumor arises along a peripheral nerve, or in a ganglioneuroma, or in a patient with neurofibromatosis type 1 (NF1), or has a metastatic character
2. the growth characteristics of the tumor is typical for a Schwann cell tumor
3. rhabdomyoblasts arise within the body of the tumor.
When a thymoma is suspected, a CT/CAT scan is generally performed to estimate the size and extent of the tumor, and the lesion is sampled with a CT-guided needle biopsy. Increased vascular enhancement on CT scans can be indicative of malignancy, as can be pleural deposits. Limited biopsies are associated with a very small risk of pneumomediastinum or mediastinitis and an even-lower risk of damaging the heart or large blood vessels. Sometimes thymoma metastasize for instance to the abdomen.
The diagnosis is made via histologic examination by a pathologist, after obtaining a tissue sample of the mass. Final tumor classification and staging is accomplished pathologically after formal surgical removal of the thymic tumor
Selected laboratory tests can be used to look for associated problems or possible tumor spread. These include: full blood count, protein electrophoresis, antibodies to the acetylcholine receptor (indicative of myasthenia), electrolytes, liver enzymes and renal function.
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.
The risk of meningioma can be reduced by maintaining a normal body weight, and by avoiding unnecessary dental x-rays.
Dermal neurofibromas are not usually surgically removed unless they are painful or disfiguring, because there are generally so many of them and they are not dangerous.
CO lasers have been used to remove dermal neurofibromas. In a paper titled "Hypertrophic Scars After Therapy with CO Laser for Treatment of Multiple Cutaneous Neurofibromas" Ostertag et al. said this about treatment by laser: “The cosmetic disfigurement is the most important issue in the decision to treat cutaneous symptoms of neurofibromatosis. Treating patients with extensive neurofibromas with [a] CO laser is still the best choice. However, it is strongly advised that a test treatment be performed to judge the effectiveness of the procedure and whether the developed scar is an acceptable trade-off.”
Surgery, with as wide a margin of removal as possible, has generally been the most effective and preferred way to attack LMS. If surgical margins are narrow or not clear of tumor, however, or in some situations where tumor cells were left behind, chemotherapy or radiation has been shown to give a clear survival benefit. While LMS tends to be resistant to radiation and chemotherapy, each case is different and results can vary widely.
LMS of uterine origin do frequently, but not always respond to hormonal treatments.
The diagnosis of NM is based on the detection of malignant cells in the CSF, the demonstration of leptomeningeal tumor cell deposits on neuroimaging, or both. CSF examination is the most useful diagnostic tool for NM. Patients with suspected NM should undergo one or two lumbar punctures, cranial magnetic resonance imaging (MRI), spinal MRI, and a radioisotope CSF flow study to rule out sites of CSF block. If the cytology remains negative and radiological studies are not definitive, consideration may be given to ventricular or lateral cervical spine CSF analysis based on the suspected site of predominant disease. Consideration of signs, symptoms, and neuroimaging can help with the placement to where CSF is drawn. Median time of diagnosis from initial primary cancer diagnosis is between 76 days and 17 months. NM diagnosis has been increasing and will continue to increase due to better primary care and longer survival time of cancer patients.
Difficulties in Diagonsis:
NM is multifocal and CSF at a particular site may show no abnormalities if the pathological site is far away. Only 50% of those suspected with NM are actually diagnosed with NM and only the presence of malignant cells in the CSF is diagnosis conclusive.
Techniques:
- MRI: Meningeal findings are described with the following characteristics: Nodular meningeal tumor, meningeal thickening >3 mm and a subjectively strong contrast enhancement. A smooth contrast enhancement of the meninges was judged to be typical for inflammatory, nonneoplastic meningitis.
- CSF cytology: is performed after drawing the CSF by lumbar puncture.
- Cytogenetic: measures chromosomal content of cells and fluorescence in situ hybridization which detects numerical and structural genetic aberrations as a sign of malignancy. This is especially useful for liquid tumors such as leukemia and lymphoma. Some of the techniques that achieve this are flow cytometry and DNA single-cell cytometry. However, cytogenetic only assist in diagnosis and is less preferred.
- Meningeal Biopsy: may be performed when all of the above criteria is inconclusive. Biopsy is only effective when performed at the region where there's enhancement on the MRI.
Ancillary testing for fibrosarcoma includes IHC, where vimentin is positive, cytokeratin and S100 are negative, and actin is variable.
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.
JCT often is described as benign, however one case of metastasis has been reported, so its malignant potential is uncertain. In most cases the tumor is encapsulated.
A blood test for protein melanoma inhibitory activity may be used to detect the presence of neurofibromas.
Clinically, hypertension, especially when severe or poorly controlled, combined with evidence of a kidney tumor via imaging or gross examination suggest a JCT. However, other kidney tumors can cause hypertension by secreting renin. JCTs have a variable appearance and have often being misdiagnosed as renal cell carcinomas; dynamic computed tomography is helpful in the differential diagnosis.
Post-operatively, the presence of renin granules in pathology specimens as well as immunohistochemical analyses could help differentiating this tumor from other primary renal tumors such as hemangiopericytoma, glomus tumor, metanephric adenoma, epithelioid angiomyolipoma, Wilms tumor, solitary fibrous tumor, and some epithelial neoplasms.
It is classified into two types, based on location in the body: peripheral PNET and CNS PNET.
Observation with close imaging follow-up may be used in select cases if a meningioma is small and asymptomatic. In a retrospective study on 43 patients, 63% of patients were found to have no growth on follow-up, and the 37% found to have growth at an average of 4 mm / year. In this study, younger patients were found to have tumors that were more likely to have grown on repeat imaging; thus are poorer candidates for observation. In another study, clinical outcomes were compared for 213 patients undergoing surgery vs. 351 patients under watchful observation. Only 6% of the conservatively treated patients developed symptoms later, while among the surgically treated patients, 5.6% developed persistent morbid condition, and 9.4% developed surgery-related morbid condition.
Observation is not recommended in tumors already causing symptoms. Furthermore, close follow-up with imaging is required with an observation strategy to rule out an enlarging tumor.