Castleman disease is diagnosed when a lymph node biopsy reveals regression of germinal centers, abnormal vascularity, and a range of hyaline vascular changes and/or polytypic plasma cell proliferation. These features can also be seen in other disorders involving excessive cytokine release, so they must be excluded before a Castleman disease diagnosis should be made.

It is essential for the biopsy sample to be tested for HHV-8 with latent associated nuclear antigen (LANA) by immunohistochemistry or PCR for HHV-8 in the blood.

In the unicentric form of the disease, surgical resection is often curative, and the prognosis is excellent.

Gastric MALT lymphoma is frequently associated (72–98%) with chronic inflammation as a result of the presence of "Helicobacter pylori", potentially involving chronic inflammation, or the action of "H. pylori" virulence factors such as CagA.

The initial diagnosis is made by biopsy of suspicious lesions on esophagogastroduodenoscopy (EGD, upper endoscopy). Simultaneous tests for "H. pylori" are also done to detect the presence of this microbe.

In other sites, chronic immune stimulation is also suspected in the pathogenesis (e.g. association between chronic autoimmune diseases such as Sjögren's syndrome and Hashimoto's thyroiditis, and MALT lymphoma of the salivary gland and the thyroid).

Of all cancers involving the same class of blood cell, 8% of cases are MALT lymphomas.

PTGC is treated by excisional biopsy and follow-up. It may occasionally recur and in a small proportion of patients has been reported to subsequently develop Hodgkin lymphoma (usually nodular lymphocyte predominant Hodgkin lymphoma).

The two types of lymphoma research are clinical or translational research and basic research. Clinical/translational research focuses on studying the disease in a defined and generally immediately patient-applicable way, such as testing a new drug in patients. Studies may focus on effective means of treatment, better ways of treating the disease, improving the quality of life for patients, or appropriate care in remission or after cures. Hundreds of clinical trials are being planned or conducted at any given time.

Basic science research studies the disease process at a distance, such as seeing whether a suspected carcinogen can cause healthy cells to turn into lymphoma cells in the laboratory or how the DNA changes inside lymphoma cells as the disease progresses. The results from basic research studies are generally less immediately useful to patients with the disease, but can improve scientists' understanding of lymphoma and form the foundation for future, more effective treatments.

Prognoses and treatments are different for HL and between all the different forms of NHL, and also depend on the grade of tumour, referring to how quickly a cancer replicates. Paradoxically, high-grade lymphomas are more readily treated and have better prognoses: Burkitt lymphoma, for example, is a high-grade tumour known to double within days, and is highly responsive to treatment. Lymphomas may be curable if detected in early stages with modern treatment.

Historically, hematological malignancies have been most commonly divided by whether the malignancy is mainly located in the blood (leukemia) or in lymph nodes (lymphomas).

However, the influential WHO Classification (published in 2001) placed a greater emphasis on cell lineage.

Relative proportions of hematological malignancies in the United States

PTGCs is characterized by:

- follicular hyperplasia (many follicles),

- focally large germinal centres, with poorly demarcated germinal centre (GC)/mantle zone interfaces (as GCs infiltrated by mantle zone lymphocytes), and

- an expanded mantle zone.

For the analysis of a suspected "hematological malignancy", a complete blood count and blood film are essential, as malignant cells can show in characteristic ways on light microscopy. When there is lymphadenopathy, a biopsy from a lymph node is generally undertaken surgically. In general, a bone marrow biopsy is part of the "work up" for the analysis of these diseases. All specimens are examined microscopically to determine the nature of the malignancy. A number of these diseases can now be classified by cytogenetics (AML, CML) or immunophenotyping (lymphoma, myeloma, CLL) of the malignant cells.

Some specific reactive lymphadenopathies with a predominantly follicular pattern:

- Rheumatoid arthritis

- Sjogren syndrome

- IgG4-related disease (IgG4-related lymphadenopathy)

- Kimura disease

- Toxoplasmosis

- Syphilis

- Castleman disease

- HIV-associated lymphadenopathy

- Progressive transformation of germinal centers (PTGC)

Follicular hyperplasia (or "reactive follicular hyperplasia" or "lymphoid nodular hyperplasia") is a type of lymphoid hyperplasia. It is caused by a stimulation of the B cell compartment. It is caused by an abnormal proliferation of secondary follicles and occurs principally in the cortex without broaching the lymph node capsule. The follicles are cytologically polymorphous, are often polarized, and vary in size and shape. Follicular hyperplasia is distinguished from follicular lymphoma in its polyclonality and lack of bcl-2 protein expression, whereas follicular lymphoma is monoclonal, and does express bcl-2).

Flow cytometry is a diagnostic tool in order to count/visualize the amount of lymphatic cells in the body. T cells, B cells and NK cells are nearly impossible to distinguish under a microscope, therefore one must use a flow cytometer to distinguish them.

Standard, and most effective, therapy to date is glandular sialadenectomy, which is associated with fairly low operative morbidity; however, in recent times, the administration of steroid (which can shrink the inflammatory lesion and is known to reduce serum IgG4 values) has been considered favorably, and may be useful in younger patients or those who refuse surgery.

Patients diagnosed as having Castleman disease but also exhibiting many of the symptoms and signs of POEMS syndrome but lacking evidence of a peripheral neuropathy and/or clonal plasma cells should not be diagnosed as having POEMS syndrome. They are better classified as having Castleman disease variant of POEMS syndrome. These patients may exhibit high blood levels of the interleukin-6 cytokine and have an inferior overall survival compared to POEMS syndrome patients. Treatment of patients with this POEMS syndrome variant who have evidence of bone lesions and/or myeloma proteins are the same as those for POEMS syndrome patients. In the absence of these features, treatment with rituximab, a monoclonal antibody preparation directed against B cells bearing the CD20 antigen, or siltuximab, a monoclonal antibody preparation directed against interleukin-6, may be justified.

In addition to tests corresponding to the above findings (such as EMG for neuropathy, CT scan, bone marrow biopsy to detect clonal plasma cells, plasma or serum protein electrophoresis to myeloma proteins, other tests can give abnormal results supporting the diagnosis of POEMS syndrome. These included raised blood levels of VEGF, thrombocytes, and/or erythrocyte parameters.

Cutaneous lymphoma, also known as lymphoma cutis, is when lymphoma involves the skin. It is characterized by a proliferation of lymphoid tissue.

There are two main classes of lymphomas that affect the skin:

- Cutaneous T-cell lymphoma

- Cutaneous B-cell lymphoma

ANKL is treated similarly to most B-cell lymphomas. Anthracycline-containing chemotherapy regimens are commonly offered as the initial therapy. Some patients may receive a stem cell transplant.

Most patients will die 2 years after diagnosis.

Following observation of the symptoms, the patients need to get complete blood counts and a bone marrow examination. If the patient has leukemia, the morphology and immunophenotype check is needed to make sure the type of leukemia.

The morphology of the blast in BAL is not certain. The cells could display both myeloid lineage and lymphoid or undifferentiated morphology. Therefore, the diagnosis cannot based on the morphology result. The immunophenotype check is the most important basis of the diagnosis of BAL.

Before 2008, the diagnosis of BAL was based on a score system proposed by the European Group for the Immunological Classification of Leukemias (EGIL) which could differentiate from other kinds of acute leukemia. The table shows this method.

If the score of only one lineage is higher than 2, the acute leukemia could be acute myeloid leukemia (AML) or acute lymphoblastic leukemia (ALL). According to the original EGIL scoring system BAL is defined when scores are over two points for both myeloid and T- or B- lymphoid lineages.

In 2008, WHO established a new and strict criteria standard for diagnosis of BAL. The presence of specific T-lymphoid antigens, cytoplasmic CD3 (cCD3), MPO and CD 19 became the most important standard for recognizing the lineage. Other B-lineage markers (CD22, CD79a, CD 10) and monocytic markers are also needed. Table 2 shows the method.

Compared with the EGIL scoring system, the current 2008 WHO criteria applied less but more specific markers to define the lineage of the blasts, and incorporated the intensity of markers expression into the diagnostic algorithm.

The diagnosis of BAL is so difficult that sometimes is misdiagnosed with AML or ALL because the morphology thus the therapy would not have a good effect.

1)positive tuberclin test

2)chest radiograph

3)CT scan

4)cytology/biopsy (FNAC)

5)AFB staining

6)mycobacterial culture

lymphadenopathy is a common biopsy finding, and may often be confused with malignant lymphoma. It may be separated into major morphologic patterns, each with its own differential diagnosis with certain types of lymphoma. Most cases of reactive follicular hyperplasia are easy to diagnose, but some cases may be confused with follicular lymphoma. There are seven distinct patterns of benign lymphadenopathy:

- Follicular hyperplasia: This is the most common type of reactive lymphadenopathy.

- Paracortical hyperplasia/Interfollicular hyperplasia: It is seen in viral infections, skin diseases, and nonspecific reactions.

- Sinus histiocytosis: It is seen in lymph nodes draining limbs, inflammatory lesions, and malignancies.

- Nodal extensive necrosis

- Nodal granulomatous inflammation

- Nodal extensive fibrosis (Connective tissue framework)

- Nodal deposition of interstitial substance

These morphological patterns are never pure. Thus, reactive follicular hyperplasia can have a component of paracortical hyperplasia. However, this distinction is important for the differential diagnosis of the cause.

Jessner lymphocytic infiltrate of the skin is a cutaneous condition characterized by a persistent papular and plaque-like skin eruption which can occur on the neck, face and back and may re-occur. This is an uncommon skin disease and is a benign collection of lymph cells. Its cause is not known and can be hereditary. It is named for Max Jessner. It is thought to be equivalent to lupus erythematosus tumidus.

It can occur as the result of ACE inhibitors and a number of medications used to treat multiple sclerosis including glatiramer acetate.

Given the difficulties of a definitive pre-operative diagnosis, the clinical entity of Küttner's tumor has so far remained significantly under-reported and under-recognized. In recent times, armed with a better understanding of the occurrences and observable features of this condition, surgeons are increasingly depending upon pre-operative ultrasonography along with Fine-needle aspiration cytological (FNAC) examinations to make an accurate presumptive diagnosis, and according to one estimate, about 44% of patients undergoing submandibular resection are found to have this condition. In the ultrasonogram, Küttner's tumor is characterized by a diffuse, heterogeneous zone of echo-shadows. The FNAC finds cells greatly reduced in number (called 'paucicellularity') along with scattered tubular ducts against a backdrop of lymphoplasmacytic infiltration and fibrous depositions. There may be a reduced but moderate number of cells and ducts enveloped in fibrous sheaths, as well as fibrous proliferation of the gland's septa. The cytologic findings by themselves may not be specific, and the diagnosis requires adjunct consideration of both the ultrasonogram and clinical presentation. Application of magnetic resonance imaging (MRI) has been tried to non-invasively examine the morphological variations in Küttner's tumor and differentiate them from those seen in malignant tumors; while MRI findings of the affected tissue and the pattern of cellular infiltration may offer some diagnostic clues for this condition, so far the results have been inconclusive.

The prognosis for BAL patients is not good which is worse than ALL and AML. Medical Blood Institute reported cases of CR rate was 31.6%, with a median remission are less than 6 months

The median survival time is only 7.5 months. The life quality is also low because the immune function of patient is damaged seriously. They have to stay in hospital and need 24h care.

In another study, the results showed that young age, normal karyotype and ALL induction therapy will have a better prognosis than Ph+, adult patients. The study shows median survival of children is 139 months versus 11 months of adults, 139 months for normal karyotype patients versus 8 months for ph+ patients.

The lesion presents in young patients, so the differential for a "polyp", especially when the lymphoid component is crushed or dominant, would include a rhabdomyosarcoma, extramedullary plasmacytoma, and a neuroendocrine adenoma of the middle ear.