The diagnosis of renal medullary carcinoma is typically made after individuals with sickle cell trait present with the typical signs and symptoms outlined above, in combination with radiographic imaging (usually abdominal/pelvic CT scan) studies and ultimately surgical biopsy and pathological examination of the tumor. Findings on radiographic examination are non-specific and can reveal a mass deep within the kidney. Histopathology studies show a distinctive pattern that can be distinguished from other renal tumors.

Blood chemistry tests are conducted if renal cell carcinoma is suspected as cancer has the potential to elevate levels of particular chemicals in blood. For example, liver enzymes such as aspartate aminotransferase [AST] and alanine aminotransferase [ALT] are found to be at abnormally high levels. The staging of the cancer can also be determined by abnormal elevated levels of calcium, which suggests that the cancer may have metastasised to the bones. In this case, a doctor should be prompted for a CT scan. Blood chemistry tests also assess the overall function of the kidneys and can allow the doctor to decide upon further radiological tests.

Ultrasonographic examination can be useful in evaluating questionable asymptomatic kidney tumours and cystic renal lesions if Computed Tomography imaging is inconclusive. This safe and non-invasive radiologic procedure uses high frequency sound waves to generate an interior image of the body on a computer monitor. The image generated by the ultrasound can help diagnose renal cell carcinoma based on the differences of sound reflections on the surface of organs and the abnormal tissue masses. Essentially, ultrasound tests can determine whether the composition of the kidney mass is mainly solid or filled with fluid.

A Percutaneous biopsy can be performed by a radiologist using ultrasound or computed tomography to guide sampling of the tumour for the purpose of diagnosis by pathology. However this is not routinely performed because when the typical imaging features of renal cell carcinoma are present, the possibility of an incorrectly negative result together with the risk of a medical complication to the patient may make it unfavourable from a risk-benefit perspective. However, biopsy tests for molecular analysis to distinguish benign from malignant renal tumours is of investigative interest.

A CT scan is the first choice modality for workup of solid masses in the kidneys. Nevertheless, hemorrhagic cysts can resemble renal cell carcinomas on CT, but they are easily distinguished with Doppler ultrasonography (Doppler US). In renal cell carcinomas, Doppler US often shows vessels with high velocities caused by neovascularization and arteriovenous shunting. Some renal cell carcinomas are hypovascular and not distinguishable with Doppler US. Therefore, renal tumors without a Doppler signal, which are not obvious simple cysts on US and CT, should be further investigated with contrast-enhanced ultrasound, as this is more sensitive than both Doppler US and CT for the detection of hypovascular tumors.

Renal medullary carcinoma is extremely rare and it is not currently possible to predict those individuals with sickle cell trait who will eventually develop this cancer. It is hoped that early detection could result in better outcomes but screening is not feasible.

The RENAL Nephrometry Scoring System is used to measure the complexity of kidney tumors for surgical excision, and is estimated by CT scan as follows:

A higher score indicates a higher difficulty in removing the tumor surgically, potentially making nephrectomy necessary.

Regardless of location, all rhabdoid tumours are highly aggressive, have a poor prognosis, and tend to occur in children less than two years of age.

2004 research showed that CCSK patients exhibit an improved relapse-free survival from a longer course of therapy when using vincristine, doxorubicin, and dactinomycin, but their long-term survival is unchanged compared with patients receiving 6 months of therapy.

In 2011, Howard proposed a refinement of the standard Cairo-Bishop definition of TLS accounting for 2 limitations:

- Two or more electrolyte laboratory abnormalities must be present simultaneously to be considered related to TLS. In fact, some patients may present with one abnormality, but later another one may develop that is unrelated to the TLS (e.g., hypocalcemia associated with sepsis).

- A 25% change from baseline should not be considered a criterion since such increases are rarely clinically important unless the value is already outside the normal range.

Moreover, any symptomatic hypocalcemia should constitute clinical TLS.

The first sign is normally a painless abdominal tumor that can be easily felt by the doctor. An ultrasound scan, computed tomography scan, or MRI scan is done first. A tumor biopsy is not typically performed due to the risk of creating fragments of cancer tissue and seeding the abdomen with malignant cells.

Staging is a standard way to describe the extent of spread of Wilms tumors, and to determine prognosis and treatments. Staging is based on anatomical findings and tumor cells pathology.

The histologic diagnosis of malignant rhabdoid tumour depends on identification of characteristic rhabdoid cells—large cells with eccentrically located nuclei and abundant, eosinophilic cytoplasm. However, the histology can be heterogeneous and the diagnosis of MRT can often be difficult. Misclassifications can occur.

In MRTs, the INI1 gene (SMARCB1)on chromosome 22q functions as a classic tumour suppressor gene. Inactivation of INI1 can occur via deletion, mutation, or acquired UPD.

In a recent study, SNP array karyotyping identified deletions or LOH of 22q in 49/51 rhabdoid tumours. Of these, 14 were copy neutral LOH (or acquired UPD), which is detectable by SNP array karyotyping, but not by FISH, cytogenetics, or arrayCGH. MLPA detected a single exon homozygous deletion in one sample that was below the resolution of the SNP array. SNP array karyotyping can be used to distinguish, for example, a medulloblastoma with an isochromosome 17q from a primary rhabdoid tumour with loss of 22q11.2. When indicated, molecular analysis of INI1 using MLPA and direct sequencing may then be employed. Once the tumour-associated changes are found, an analysis of germline DNA from the patient and the parents can be done to rule out an inherited or de novo germline mutation or deletion of INI1, so that appropriate recurrence risk assessments can be made.

"FLCN" mutations are detected by sequencing in 88% of probands with Birt–Hogg–Dubé syndrome. This means that some people with the clinical diagnosis have mutations that are not detectable by current technology, or that mutations in another currently unknown gene could be responsible for a minority of cases. In addition, amplifications and deletions in exonic regions are also tested. Genetic testing can be useful to confirm the clinical diagnosis of and to provide a means of determining other at-risk individuals in a family even if they have not yet developed BHD symptoms.

Birt–Hogg–Dubé can be difficult to diagnose from symptoms alone, because hereditary renal cancers, pneumothorax, and cutaneous tumors occur with other syndromes. Hereditary bilateral, multifocal kidney tumors similar to those seen in BHDcan occur with von Hippel–Lindau disease (clear cell renal cell carcinoma), hereditary papillary renal cancer (papillary renal cell carcinoma), and hereditary leiomyomatosis and renal cell cancer syndrome. They are differentiated with examination of the tumors' histology.

Hereditary recurrent pneumothorax or pulmonary cysts are associated with Marfan syndrome, Ehlers–Danlos syndrome, Tuberous Sclerosis Complex (TSC), alpha1-antitrypsin deficiency, and cystic fibrosis. Non-hereditary recurrent pneumothorax and/or pulmonary cysts can occur with Langerhans cell histiocytosis and lymphangioleiomyomatosis. These conditions are differentiated from Birt–Hogg–Dubé through examining the patient history and performing a physical examination. In women suspected to have the disease, ruling out pulmonary or thoracic endometriosis may be necessary.

Though fibrofolliculomas are unique to Birt–Hogg–Dubé, they may present with an ambiguous appearance and must be confirmed histologically. Other diseases can mimic the dermatologic manifestations of BHD, including tuberous sclerosis complex, Cowden syndrome, familial trichoepitheliomas, and multiple endocrine neoplasia type 1. Tuberous sclerosis must be distinguished because both disorders can present with angiofibromas on the face, though they are more common in tuberous sclerosis.

People about to receive chemotherapy for a cancer with a high cell turnover rate, especially lymphomas and leukemias, should receive prophylactic oral or IV allopurinol (a xanthine oxidase inhibitor, which inhibits uric acid production) as well as adequate IV hydration to maintain high urine output (> 2.5 L/day). Allopurinol mechanically blocks rasburicase's operation to solubilize.

Rasburicase is an alternative to allopurinol and is reserved for people who are high-risk in developing TLS. It is a synthetic urate oxidase enzyme and acts by degrading uric acid. However, it's not clear if it results in any important benefits as of 2014.

Alkalization of the urine with acetazolamide or sodium bicarbonate is controversial. Routine alkalization of urine above pH of 7.0 is not recommended. Alkalization is also not required if uricase is used.

Diagnosis of mesoblastic nephroma and its particular type (i.e. classic, mixed, or cellular) is made by histological examination of tissues obtained at surgery. Besides its histological appearance, various features of this disease aid in making a differential diagnosis that distinguish it from the following childhood neoplasms:

- Wilm's tumor is the most common childhood kidney neoplasm, representing some 85% of cases. Unlike mesoblastic nephroma, 3 years of age. Bilateral kidney tumors, concurrent birth defects, and/or metastatic disease at presentation favor a diagnosis of Wilm's tumor.

- congenital infantile sarcoma is a rare aggressive sarcoma typically presenting in the lower extremities, head, or neck of infants during their first year of life. The histology, association with the "ETV6-NRTK3" fusion gene along with certain chromosome trisomies, and the distribution of markers for cell type (i.e. cyclin D1 and Beta-catenin) within this tumor are the same as those found in cellular mesoblastic nephroma. Mesoblastic nephroma and congenital infantile sarcoma appear to be the same diseases with mesoblastic lymphoma originating in the kidney and congenital infantile sarcoma originating in non-renal tissues.

- Rhabdoid tumor, which accounts for 5-510% of childhood kidney neoplasms, occurs predominantly in children from 1 to 2 years of age. Unlike mesoblastic nephroma, rhabdoid tumors may present with tumors in other tissues including in ~13% of cases, the brain. Rhabdoid tumors have a distinctive histology and abnormalities (i.e. loss of heterozygosity, single nucleotide polymorphism, and deletions) in chromosome 22.

- Clear cell sarcoma of the kidney, which is responsible for 5-10% of childhood pediatric tumors, occurs predominantly in children from 2 to 3 years of age. Unlike meoblastic nephorma, clear cell sarcoma of the kidney presents with metastasis, particularly to bone, in 5-6% of cases; it histology is diverse and has been mistaken for mesoblastic nephroma. One chromosomal translocations t,(10;17)(q22;p13), has been repeatedly reported to be associated with clear cell sarcoma of the kidney.

- Infantile myofibromatosis is a fibrous tumor of infancy and childhood most commonly presenting during the first 2 years of life as a single subcutaneous nodule of the head and neck region or less commonly as multiple lesions of skin, muscle, bone, and in ~33% of these latter cases, visceral organs. All of these lesions have an excellent prognosis and can regress spontaneously except for those in which there is visceral involvement where the prognosis is poor. While infantile myofibromatosis and classic mesoblastic nephroma have been suggested to be the same diseases because of their very similar histology, studies on the distribution of cell-type markers (i.e. cyclin D1 and Beta-catenin) indicate that they have different cellular origins.

The United States' NIH estimates for 2013 around 64,770 new cases of kidney cancer and 13,570 deaths from the disease.

The incidence of kidney cancer is also increasing in the United States. This is thought to be a real increase, not only due to changes in the way the disease is diagnosed.

Based on a survey of >800, surgical removal of the entire involved kidney plus the peri-renal fat appeared curative for the majority of all types of mesoblastic nephroma; the patient overall survival rate was 94%. Of the 4% of non-survivors, half were due to surgical or chemotherapeutic treatments. Another 4% of these patients suffered relapses, primarily in the local area of surgery rare cases of relapse due to lung or bone metastasis.. About 60% of these recurrent cases had a complete remission following further treatment. Recurrent disease was treated with a second surgery, radiation, and/or chemotherapy that often vincristine and actinomycin treatment. Removal of the entire afflicted kidney plus the peri-renal fat appears critical to avoiding local recurrences. In general, patients who were older than 3 months of age at diagnosis or had the cellular form of the disease, stage III disease, or involvement of renal lymph nodes had a higher recurrence rate. Among patients with these risk factors, only those with lymph node involvement are recommended for further therapy.

It has been suggested that mesoblastic nephroma patients with lymph node involvement or recurrent disease might benefit by adding the ALK inhibitor, crizotinib, or a tyrosine kinase inhibitor, either larotrectinib or entrectinib, to surgical, radiation, and/or chemotherapy treatment regimens. These drugs inhibit NTRK3's tyrosine kinase activity. Crizotinib has proven useful in treating certain cases of acute lymphoblastic leukemia that are associated with the "ETV6-NTRK3" fusion gene while larotrectinib and entrectinib have been useful in treating various cancers (e.g. a metastatic sarcoma, papillary thyroid cancer, non-small-cell lung carcinoma, gastrointestinal stromal tumor, mammary analog secretory carcinoma, and colorectal cancer) that are driven by mutated, overly active tyrosine kinases. Relevant to this issue, a 16-month-old girl with infantile fibrosarcoma harboring the "ETV6–NTRK3" fusion gene was successfully trated with larotrectinib. The success of these drugs, howwever, will likely depend on the relative malignancy-promoting roles of ETV6-NTRK3 protein's tyrosine kinase activity, the lose of ETV6-related transcription activity accompanying formation of ETV6-NTRK3 protein, and the various trisomy chromosomes that populate mesoblastic nephroma.

Research in 2005 showed that CCSK can arise within a renal mesenchymal cell that shows a wide variety of neural markers. Typical presentation is between 1 and 4 years of age, and a 2:1 male-to-female ratio is observed.

The most recent estimates of incidence of kidney cancer suggest that there are 63,300 new cases annually in the EU25. In Europe, kidney cancer accounts for nearly 3% of all cancer cases.

The standard work-up for AT/RT includes:

- Magnetic resonance imaging (MRI) of the brain and spine

- Lumbar puncture to look for M1 disease

- Computed tomography (CT) of chest and abdomen to check for a tumor

- Bone marrow aspiration to check for bone tumors. Sometimes the physician will perform a stem cell transplant

- Bone marrow biopsy

- Bone scan

The initial diagnosis of a tumor is made with a radiographic study (MRI or CT-). If CT was performed first, an MRI is usually performed as the images are often more detailed and may reveal previously undetected metastatic tumors in other locations of the brain. In addition, an MRI of the spine is usually performed. The AT/RT tumor often spreads to the spine. AT/RT is difficult to diagnose only from radiographic study; usually, a pathologist must perform a cytological or genetic analysis.

Examination of the cerebrospinal fluid is important (CSF), as one-third of patients will have intracranial dissemination with involvement of the CSF. Large tumor cells, eccentricity of the nuclei, and prominent nucleoli are consistent findings. Usually only a minority of AT/RT biopsies have rhabdoid cells, making diagnosis more difficult. Increasingly it is recommended that a genetic analysis be performed on the brain tumor, especially to find if a deletion in the INI1/hSNF5 gene is involved (appears to account for over 80% of the cases). The correct diagnosis of the tumor is critical to any protocol. Studies have shown that 8% to over 50% of AT/RT tumors are diagnosed incorrectly.

The complex cyst can be further evaluated with doppler ultrasonography, and for Bosniak classification and follow-up of complex cysts, either contrast-enhanced ultrasound (CEUS) or contrast CT is used.

DSRCT is frequently misdiagnosed. Adult patients should always be referred to a sarcoma specialist. This is an aggressive, rare, fast spreading tumor and both pediatric and adult patients should be treated at a sarcoma center.

There is no standard protocol for the disease; however, recent journals and studies have reported that some patients respond to high-dose (P6 Protocol) chemotherapy, maintenance chemotherapy, debulking operation, cytoreductive surgery, and radiation therapy. Other treatment options include: hematopoietic stem cell transplantation, intensity-modulated radiation Therapy, radiofrequency ablation, stereotactic body radiation therapy, intraperitoneal hyperthermic chemoperfusion, and clinical trials.

This system is more directly focused on the most appropriate management. These alternatives are broadly to ignore the cyst, schedule follow-up or perform a surgical excision of it. When a cyst shows discrepancy in severity across categories, it is the most worrisome feature that is used in deciding about management. There is no established rule regarding the follow-up frequency, but one possibility is after 6 months, which can later be doubled if unchanged.

Because this is a rare tumor, not many family physicians or oncologists are familiar with this disease. DSRCT in young patients can be mistaken for other abdominal tumors including rhabdomyosarcoma, neuroblastoma, and mesenteric carcinoid. In older patients DSRCT can resemble lymphoma, peritoneal mesothelioma, and peritoneal carcinomatosis. In males DSRCT may be mistaken for germ cell or testicular cancer while in females DSRCT can be mistaken for Ovarian cancer. DSRCT shares characteristics with other small-round blue cell cancers including Ewing's sarcoma, acute leukemia, small cell mesothelioma, neuroblastoma, primitive neuroectodermal tumor, rhabdomyosarcoma, and Wilms' tumor.