Primary mediastinal B-cell lymphoma

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Primary mediastinal large B-cell lymphoma
Primary mediastinal large B-cell lymphoma - very high mag.jpg
Micrograph of a primary mediastinal large B-cell lymphoma. H&E stain.
Specialty Hematology and oncology

Primary mediastinal B-cell lymphoma, abbreviated PMBL or PMBCL, is a rare type of lymphoma that forms in the mediastinum (the space in between the lungs) and predominantly affects young adults. [1] [2] [3]

Contents

While it had previously been considered a subtype of diffuse large B-cell lymphoma when first described in the early 1980s, [3] [4] the World Health Organization no longer classifies it as such, based on distinct clinicopathologic and molecular features. [5]

Pathophysiology

PMLBCL arises from a putative thymic peripheral B cell. [6] [7] It has several distinctive biological features. [6] Molecular analysis shows that PMLBCL is distinct from other types of diffuse large B-cell lymphomas (DLBCL). [7] MAL gene expression is seen in 70%, unlike other diffuse large B-cell lymphomas. [8] : 370  Gene expression profiling shows considerable variance from other DLBCLs and similarity to Hodgkin disease. [9] : 290–293 

PMLBCL is CD20 positive, expresses pan-B markers including CD79a, and has clonal immunoglobulin gene rearrangements and mRNA but paradoxically does not express cytoplasmic or cell surface immunoglobulin. [8] : 370 

Clinically, PMLBCL is unusual in several respects. Despite 80% PMLBCL being stage I or II, the presenting anterior mediastinal mass is often over 10 cm and is locally invasive of lung, chest wall, pleura, and pericardium. [6] At initial presentation, PMLBCL is usually confined to mediastinum, but its bulk, rather than additional adenopathy, can sometimes be palpated at the low neck. [6] Increased LDH is seen in approximately 75%, [8] : 370  [6] but unlike other large cell lymphomas, no increase in beta-2 microglobulin is seen even when bulky [8] : 370  which may relate to defective major histocompatibility complex expression. [8] : 370 

Diagnosis

Diagnosis requires a biopsy, so that the exact type of tissue can be determined by examination under a microscope. PMBCL is a distinct type of lymphoma that shares some features with both diffuse large B-cell lymphoma, and nodular sclerosing Hodgkin lymphoma (NSHL). [10] Tumors that are even more closely related to NSHL than typical for PMBCL are called gray zone lymphoma. [10]

Treatment

Multiagent chemotherapy is recommended, but the preferred regimen is controversial, as is consolidative radiotherapy. [6] [11] [12] [13]

Treatment commonly begins with either R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, prednisolone) or DA-EPOCH-R (dose-adjusted etoposide, prednisolone, vincristine, cyclophosphamide, doxorubicin, rituximab). [14] Other, more intense, regimens may be more effective. [10] PD-1 and PD-L1 inhibitors can be used. [3]

Radiation therapy may be added, especially if chemotherapy does not seem sufficient on its own. [14] Radiation may cause other health problems later, such as breast cancer, and there is some debate about the best approach to it. [10] [3]

FDG-PET scanning is not as useful for predicting treatment success in PMBCL as it is in other lymphomas. [10] [3]

Prognosis

Most people with PMBCL are successfully treated and survive for many years. However, if the initial treatment is unsuccessful, or if it returns, the long-term prognosis is worse. [14] Relapses generally appear within 12 to 18 months after the completion of treatment. [10]

Epidemiology

This lymphoma is most commonly seen in women between the age of 20 and 40. [10]

See also

References

  1. ↑ Johnson PW, Davies AJ (2008). "Primary mediastinal B-cell lymphoma". Hematology. American Society of Hematology. Education Program. 2008: 349–58. doi: 10.1182/asheducation-2008.1.349 . PMID   19074109.
  2. ↑ Coso D, Rey J, Bouabdallah R (February 2010). "[Primary mediastinal B-cell lymphoma]". Revue de Pneumologie Clinique. 66 (1): 32–5. doi:10.1016/j.pneumo.2009.12.007. PMID   20207294.
  3. 1 2 3 4 5 Yu, Yating; Dong, Xifeng; Tu, Meifeng; Wang, Huaquan (November 2021). "Primary mediastinal large B cell lymphoma". Thoracic Cancer. 12 (21): 2831–2837. doi:10.1111/1759-7714.14155. PMC   8563158 .
  4. ↑ "Types of Non-Hodgkin Lymphoma". www.cancer.org. Retrieved 2017-09-28.
  5. ↑ "Primary mediastinal large B-cell lymphoma". ashpublications.org/blood/article/140/9/955/476814/Primary-mediastinal-large-B-cell-lymphoma.
  6. 1 2 3 4 5 6 Armitage, JO; Mauch PM; Harris NL; et al. (2010). "Chapter 21". Non-Hodgkin Lymphomas (2nd ed.). Lippincott Williams & Wilkins. ISBN   9780781791168.
  7. 1 2 Martelli M, Di Rocco A, Russo E, et al. (2015). "Primary mediastinal lymphoma: diagnosis and treatment options". Expert Rev Hematol. 8 (2): 173–86. doi:10.1586/17474086.2015.994604. hdl: 11573/780924 . PMID   25537750. S2CID   23040185.
  8. 1 2 3 4 5 Jaffe, ES; Harris NL; Vardiman JW; Campo E; Arber DA (2011). Hematopathology (1st ed.). Elsevier Saunders. ISBN   9780721600406.
  9. ↑ Sweetenham, J. Lymphomas (Emerging Cancer Therapeutics V3 I2). Demos. November 2, 2012. ISBN   9781936287789
  10. 1 2 3 4 5 6 7 Dunleavy K, Wilson WH (January 2015). "Primary mediastinal B-cell lymphoma and mediastinal gray zone lymphoma: do they require a unique therapeutic approach?". Blood. 125 (1): 33–9. doi:10.1182/blood-2014-05-575092. PMC   4281829 . PMID   25499450.
  11. ↑ "Non-Hodgkin's Lymphoma" (PDF). Archived from the original (PDF) on May 14, 2005.
  12. ↑ Faris JE, LaCasce AS (2009). "Primary mediastinal large B-cell lymphoma". Clin Adv Hematol Oncol. 7 (2): 125–33. PMID   19367254.
  13. ↑ Dabrowska-Iwanicka A, Walewski JA (2014). "Primary mediastinal large B-cell lymphoma". Curr Hematol Malig Rep. 9 (3): 273–83. doi:10.1007/s11899-014-0219-0. PMC   4180024 . PMID   24952250.
  14. 1 2 3 Lees C, Keane C, Gandhi MK, Gunawardana J (February 2019). "Biology and therapy of primary mediastinal B-cell lymphoma: current status and future directions". British Journal of Haematology. 185 (1): 25–41. doi:10.1111/bjh.15778. PMC   6594147 . PMID   30740662.
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