Lymphoma

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Lymphoma
Lymphoma macro.jpg
Classification and external resources
Specialty Hematology and oncology
ICD-10 C81-C96
ICD-9-CM 202.8
ICD-O 9590–9999
MedlinePlus 000580 000581
Patient UK Lymphoma
MeSH D008223
[[[d:Lua error in Module:Wikidata at line 863: attempt to index field 'wikibase' (a nil value).|edit on Wikidata]]]

Lymphoma is any of a group of blood cell tumors that develop from lymphatic cells. The name often refers to just the cancerous ones rather than all such tumors.[1] Signs and symptoms may include enlarged lymph nodes, fever, drenching sweats, unintended weight loss, itching, and feeling tired.[2][3] The enlarged lymph nodes are usually painless.[2] The sweats are most common at night.[2][3]

There are dozens of subtypes of lymphomas.[4] The two main categories of lymphomas are Hodgkin lymphomas (HL) and the non-Hodgkin lymphomas (NHL).[5] The World Health Organization (WHO) includes two other categories as types of lymphoma: multiple myeloma and immunoproliferative diseases.[6] About 90% of lymphomas are non-Hodgkin lymphomas.[5][7] Lymphomas and leukemias are a part of the broader group of tumors of the hematopoietic and lymphoid tissues.[8]

Risk factors for Hodgkin lymphoma include infection with Epstein–Barr virus and a history of the disease in the family.[2] Risk factors for common types of non-Hodgkin lymphomas include autoimmune diseases, HIV/AIDS, infection with human T-lymphotropic virus, eating a large amount of meat and fat, immunosuppressant medications, and some pesticides.[3] Diagnosis, if enlarged lymph nodes are present, is usually by lymph node biopsy.[2][3] Blood, urine, and bone marrow testing may also be useful in the diagnosis.[3] Medical imaging may then be done to determine if and where the cancer has spread.[2][3] Lymphoma most often spreads to the lungs, liver, and/or brain.[2][3]

Treatment may involve one or more of the following: chemotherapy, radiation therapy, targeted therapy, and surgery.[2][3] In some non-Hodgkin lymphomas, an increased amount of protein produced by the lymphoma cells causes the blood to become so thick that plasmapheresis is performed to remove the protein.[3] Watchful waiting may be appropriate for certain types.[3] The outcome depends on the subtype with some being curable and treatment prolongs survival in most.[5] The five-year survival rate in the United States for all Hodgkin lymphoma subtypes is 85%,[9] while that for non-Hodgkin lymphomas is 69%.[10] Worldwide, lymphomas developed in 566,000 people in 2012 and caused 305,000 deaths.[6] They make up 3–4% of all cancers, making them as a group the seventh-most common form.[6][11] In children, they are the third-most common cancer.[12] They occur more often in the developed world than the developing world.[6]

Signs and symptoms

Lymphoma and lymphatic system

Lymphoma may present with certain nonspecific symptoms; if the symptoms are persistent, an evaluation to determine their cause, including possible lymphoma, should be undertaken.

Diagnosis

Lymphoma is definitively diagnosed by a lymph node biopsy, meaning a partial or total excision of a lymph node examined under the microscope.[15] This examination reveals histopathological features that may indicate lymphoma. After lymphoma is diagnosed, a variety of tests may be carried out to look for specific features characteristic of different types of lymphoma. These include:

Classification

Lymph node with mantle cell lymphoma (low-power view, H&E)

Lymphomas sensu stricto are any neoplasms of the lymphatic tissues (lympho- + -oma) .[16] The main classes are malignant neoplasms (that is, cancers) of the lymphocytes, a type of white blood cell that belongs to both the lymph and the blood and pervades both. Thus, lymphomas and leukemias are both tumors of the hematopoietic and lymphoid tissues, and as lymphoproliferative disorders, lymphomas and lymphoid leukemias are closely related, to the point that some of them are unitary disease entities that can be called by either name (for example, adult T-cell leukemia/lymphoma).

Several classification systems have existed for lymphoma, which use histological and other findings to divide lymphoma into different categories. The classification of a lymphoma can affect treatment and prognosis. Classification systems generally classify lymphoma according to:

  • Whether or not it is a Hodgkin lymphoma
  • Whether the cell that is replicating is a T cell or B cell
  • The site from which the cell arises

Hodgkin lymphoma

Hodgkin lymphoma is one of the most commonly known types of lymphoma,[citation needed] and differs from other forms of lymphoma in its prognosis and several pathological characteristics. A division into Hodgkin and non-Hodgkin lymphomas is used in several of the older classification systems. A Hodgkin lymphoma is marked by the presence of a type of cell called the Reed–Sternberg cell.[17][18]

Non-Hodgkin lymphomas

Non-Hodgkin lymphomas, which are defined as being all lymphomas except Hodgkin lymphoma, are more common than Hodgkin lymphoma. A wide variety of lymphomas are in this class, and the causes, the types of cells involved, and the prognosis vary by type. The incidence of non-Hodgkin lymphoma increases with age. It is further divided into several subtypes.

WHO classification

The WHO classification, published in 2001 and updated in 2008,[19][20] is based upon the foundations laid within the "revised European-American lymphoma classification" (REAL). This system groups lymphomas by cell type (i.e. the normal cell type that most resembles the tumor) and defining phenotypic, molecular, or cytogenetic characteristics. The five groups are shown in the table. Hodgkin lymphoma is considered separately within the WHO and preceding classifications, although it is recognized as being a tumor of, albeit markedly abnormal, lymphocytes of mature B cell lineage.

Of the many forms of lymphoma, some are categorized as indolent (e.g. small lymphocytic lymphoma), compatible with a long life even without treatment, whereas other forms are aggressive (e.g. Burkitt's lymphoma), causing rapid deterioration and death. However, most of the aggressive lymphomas respond well to treatment and are curable. The prognosis, therefore, depends on the correct diagnosis and classification of the disease, which is established after examination of a biopsy by a pathologist (usually a hematopathologist).[21]

Lymphoma subtypes (WHO 2008)

Previous classifications

Several previous classifications have been used, including Rappaport 1956, Lennert / Kiel 1974, BNLI, Working formulation (1982), and REAL (1994).

The Working formulation of 1982 was a classification of non-Hodgkin lymphoma. It excluded the Hodgkin lymphomas and divided the remaining lymphomas into four grades (low, intermediate, high, and miscellaneous) related to prognosis, with some further subdivisions based on the size and shape of affected cells. This purely histological classification included no information about cell surface markers, or genetics, and it made no distinction between T-cell lymphomas and B-cell lymphomas. It was widely accepted at the time of its publication, but is now obsolete.[28] It is still used by some cancer agencies for compilation of lymphoma statistics and historical rate comparisons.[citation needed]

In 1994, the Revised European-American Lymphoma (REAL) classification applied immunophenotypic and genetic features in identifying distinct clinicopathologic entities among all the lymphomas except Hodgkin lymphoma.[29] For coding purposes, the ICD-O (codes 9590–9999)[30] and ICD-10 (codes C81-C96)[31] are available.

Staging

Mantle cell lymphoma: Notice the irregular nuclear contours of the medium-sized lymphoma cells and the presence of a pink histiocyte. By immunohistochemistry, the lymphoma cells expressed CD20, CD5, and Cyclin D1 (high-power view, H&E)
Hodgkin lymphoma, nodular lymphocyte predominant (low-power view): Notice the nodular architecture and the areas of "mottling".(H&E)
Hodgkin lymphoma, nodular lymphocyte predominant (high-power view): Notice the presence of L&H cells, also known as "popcorn cells". (H&E)
Diagram showing common sites where lymphoma spreads

After a diagnosis and before treatment, a cancer is staged. This refers to determining if the cancer has spread, and if so, whether locally or to distant sites. Staging is reported as a grade between I (confined) and IV (spread). Staging is carried out because the stage of a cancer impacts its prognosis and treatment.[citation needed]

The Ann Arbor staging system is routinely used for staging of both HL and NHL. In this staging system, I represents a localized disease contained within a lymph node, II represents the presence of lymphoma in two or more lymph nodes, III represents spread of the lymphoma to both sides of the diaphragm, and IV indicates tissue outside a lymph node.[citation needed]

CT scan or PET scan imaging modalities are used to stage a cancer.[citation needed]

Age and poor performance status are established poor prognostic factors, as well.[32]

Treatment

Prognoses and treatments are different for HL and between all the different forms of NHL,[33] 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:[citation needed] 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.

Low-grade lymphomas

Many low-grade lymphomas remain indolent for many years. Treatment of the nonsymptomatic patient is often avoided. In these forms of lymphoma, such as follicular lymphoma, watchful waiting is often the initial course of action. This is carried out because the harms and risks of treatment outweigh the benefits.[34] If a low-grade lymphoma is becoming symptomatic, radiotherapy or chemotherapy are the treatments of choice; although they do not cure the lymphoma, they can alleviate the symptoms, particularly painful lymphadenopathy. Patients with these types of lymphoma can live near-normal lifespans, but the disease is incurable. Some centers advocate the use of single agent rituximab in the treatment of follicular lymphoma rather than the wait and watch approach. Watchful waiting is not a good strategy for all patients, as it leads to significant distress and anxiety in some patients. It has been equated with watch and worry.[35]

High-grade lymphomas

Treatment of some other, more aggressive, forms of lymphoma[which?] can result in a cure in the majority of cases, but the prognosis for patients with a poor response to therapy is worse.[36] Treatment for these types of lymphoma typically consists of aggressive chemotherapy, including the CHOP or R-CHOP regimen. A number of people are cured with first-line chemotherapy. Most patients relapse within the first two years, and the relapse risk drops significantly thereafter.[37] For people who relapse, high-dose chemotherapy followed by autologous stem cell transplantation is a proven approach.[38]

Hodgkin lymphoma

Hodgkin lymphoma typically is treated with radiotherapy alone, as long as it is localized.[39]

Advanced Hodgkin disease requires systemic chemotherapy, sometimes combined with radiotherapy.[40] Chemotherapy used includes the ABVD regimen, which is commonly used in the United States. Other regimens used in the management of Hodgkin lymphoma include BEACOPP and Stanford V. Considerable controversy exists regarding the use of ABVD or BEACOPP. Briefly, both regimens are effective, but BEACOPP is associated with more toxicity. Encouragingly, a significant number of people who relapse after ABVD can still be salvaged by stem cell transplant.[41]

Palliative care

Palliative care, a specialized medical care focused on the symptoms, pain, and stress of a serious illness, is recommended by multiple national cancer treatment guidelines as an accompaniment to curative treatments for people suffering from lymphoma.[42][43] It is used to address both the direct symptoms of lymphoma and many unwanted side effects that arise from treatments.[44][45] Palliative care can be especially helpful for children who develop lymphoma, helping both children and their families deal with the physical and emotional symptoms of the disease.[44][46][47][48] For these reasons, palliative care is especially important for patients requiring bone marrow transplants.[49][50]

Prognosis

The lymph nodes where lymphoma most commonly develops
Five-year relative survival by stage at diagnosis[51]
Stage at diagnosis Five-year relative
survival (%)
Percentage
of cases (%)
Localized (confined to primary site) 82.1 27
Regional (spread to regional lymph nodes) 77.5 19
Distant (cancer has metastasized) 59.9 45
Unknown (unstaged) 67.5 9

Epidemiology

Age-standardized death from lymphomas and multiple myeloma per 100,000 inhabitants in 2004[52]
  no data
  less than 1.8
  1.8–3.6
  3.6–5.4
  5.4–7.2
  7.2–9
  9–10.8
  10.8–12.6
  12.6–14.4
  14.4–16.2
  16.2–18
  18–19.8
  more than 19.8

Lymphoma is the most common form of hematological malignancy, or "blood cancer", in the developed world.

Taken together, lymphomas represent 5.3% of all cancers (excluding simple basal cell and squamous cell skin cancers) in the United States and 55.6% of all blood cancers.[53]

According to the U.S. National Institutes of Health, lymphomas account for about 5%, and Hodgkin lymphoma in particular accounts for less than 1% of all cases of cancer in the United States.

Because the whole system is part of the body's immune system, patients with a weakened immune system such as from HIV infection or from certain drugs or medication also have a higher incidence of lymphoma.[54]

History

Thomas Hodgkin published the first description of lymphoma in 1832, specifically of the form named after him.[55] Since then, many other forms of lymphoma have been described.

Research

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.[56]

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,[57] but can improve scientists' understanding of lymphoma and form the foundation for future, more effective treatments.

An example of basic science research in lymphomas is the study of short non-coding RNAs named microRNAs (miRNAs). They have important functions in lymphoma biology. In malignant B cells, miRNAs participate in pathways fundamental to B cell development, such as B cell receptor (BCR) signalling, B cell migration/adhesion, cell-cell interactions in immune niches, and the production and class-switching of immunoglobulins.[58] MiRNAs influence B cell maturation, generation of pre-, marginal zone, follicular, B1, plasma and memory B cells.[58]

Other animals

References

  1. Taylor, Elizabeth J. (2000). Dorland's Illustrated medical dictionary (29th ed.). Philadelphia: Saunders. p. 1038. ISBN 0721662544.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  2. 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 "General Information About Adult Hodgkin Lymphoma". National Cancer Institute. 2014-04-23. Retrieved 20 June 2014.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  3. 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 "General Information About Adult Non-Hodgkin Lymphoma". National Cancer Institute. 2014-04-25. Retrieved 20 June 2014.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  4. Aditya Bardia (2010). Johns Hopkins Patients' Guide to Lymphoma. Jones & Bartlett Learning. p. 6. ISBN 9781449631413.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  5. 5.0 5.1 5.2 The Lymphoma Guide Information for Patients and Caregivers (pdf). Leukemia and Lymphoma Society. 2013. Retrieved 20 June 2014.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  6. 6.0 6.1 6.2 6.3 World Cancer Report 2014. World Health Organization. 2014. pp. Chapter 5.13. ISBN 9283204298.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  7. "Lymphoma". NCI. Retrieved 13 June 2014.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  8. Lua error in Module:Citation/CS1/Identifiers at line 47: attempt to index field 'wikibase' (a nil value).
  9. "Hodgkin Lymphoma—SEER Stat Fact Sheets". Seer.cancer.gov. Retrieved 2012-08-26.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  10. "SEER Stat Fact Sheets: Non-Hodgkin Lymphoma". NCI. Retrieved 18 June 2014.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  11. Marcus, Robert (2013). Lymphoma : pathology, diagnosis and treatment (Second ed.). p. 1. ISBN 9781107010598.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  12. Tepper, John E. Niederhuber, James O. Armitage, James H. Doroshow, Michael B. Kastan, Joel E. (2014). "Childhood lymphoma". Abeloff's clinical oncology (Fifth ed.). p. Chapter 97. ISBN 1455728659.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  13. 13.0 13.1 13.2 13.3 13.4 13.5 "About Lymphoma". Lymphoma Research Foundation. Retrieved 22 December 2012.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  14. 14.0 14.1 14.2 14.3 14.4 14.5 14.6 14.7 "Warning Signs of Lymphoma — First Signs of Lymphoma". Lymphoma.about.com. Retrieved 2012-12-01.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  15. Mallick, Indranil. "How Is Lymphoma Diagnosed?". lymphoma.about.com. Retrieved 22 December 2012.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  16. Elsevier, Dorland's Illustrated Medical Dictionary, Elsevier.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  17. National Cancer Institute, "Hodgkin Lymphoma", http://www.cancer.gov/cancertopics/types/hodgkin, accessed on 2013-08-05
  18. National Cancer Institute. "What You Need To Know About Hodgkin Lymphoma". U.S. Dept of Health and Human Services, (online at http://www.cancer.gov/cancertopics/wyntk/hodgkin.pdf), pg 4.
  19. 19.0 19.1 Jaffe, ES (2011). Hematopathology (1st ed.). Elsevier Saunders. ISBN 9780721600406. Unknown parameter |coauthors= ignored (help)<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  20. Swerdlow, Steven H.; International Agency for Research on Cancer; World Health Organization (2008). WHO classification of tumours of haematopoietic and lymphoid tissues. World Health Organization classification of tumours. 2 (4th ed.). International Agency for Research on Cancer. ISBN 9789283224310.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  21. Wagman LD. (2008). "Principles of Surgical Oncology". In Pazdur R, Wagman LD, Camphausen KA, Hoskins WJ. Cancer Management: A Multidisciplinary Approach (11th ed.). CMPMedica. ISBN 9781891483622. <templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  22. "Chronic Leukemias". The Merck Manual of Geriatrics.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  23. Lymphoma, Follicular at eMedicine
  24. 24.0 24.1
    50% for limited stage: Lua error in Module:Citation/CS1/Identifiers at line 47: attempt to index field 'wikibase' (a nil value).
    70% for advanced stage: Lua error in Module:Citation/CS1/Identifiers at line 47: attempt to index field 'wikibase' (a nil value).
  25. Turgeon, Mary Louise (2005). Clinical Hematology: Theory and Procedures. 936 (4 ed.). Lippincott Williams & Wilkins. pp. 285–6. ISBN 978-0-7817-5007-3.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  26. Lua error in Module:Citation/CS1/Identifiers at line 47: attempt to index field 'wikibase' (a nil value).
  27. Lua error in Module:Citation/CS1/Identifiers at line 47: attempt to index field 'wikibase' (a nil value).
  28. Lua error in Module:Citation/CS1/Identifiers at line 47: attempt to index field 'wikibase' (a nil value).
  29. Non-Hodgkin Lymphoma at eMedicine
  30. Archived June 27, 2004 at the Wayback Machine
  31. who.int
  32. International Prognostic Index N Engl J Med. 1993;329(14):987–94
  33. Sweetenham JW (November 2009). "Treatment of lymphoblastic lymphoma in adults". Oncology (Williston Park, N.Y.). 23 (12): 1015–20. PMID 20017283.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  34. Lua error in Module:Citation/CS1/Identifiers at line 47: attempt to index field 'wikibase' (a nil value).
  35. Lua error in Module:Citation/CS1/Identifiers at line 47: attempt to index field 'wikibase' (a nil value).
  36. Lua error in Module:Citation/CS1/Identifiers at line 47: attempt to index field 'wikibase' (a nil value).
  37. Lua error in Module:Citation/CS1/Identifiers at line 47: attempt to index field 'wikibase' (a nil value).
  38. Lua error in Module:Citation/CS1/Identifiers at line 47: attempt to index field 'wikibase' (a nil value).
  39. Lua error in Module:Citation/CS1/Identifiers at line 47: attempt to index field 'wikibase' (a nil value).
  40. Lua error in Module:Citation/CS1/Identifiers at line 47: attempt to index field 'wikibase' (a nil value).
  41. Lua error in Module:Citation/CS1/Identifiers at line 47: attempt to index field 'wikibase' (a nil value).
  42. Lua error in Module:Citation/CS1/Identifiers at line 47: attempt to index field 'wikibase' (a nil value).
  43. *The American Society of Clinical Oncology made this recommendation based on various cancers. See American Society of Clinical Oncology, "Five Things Physicians and Patients Should Question" (PDF), Choosing Wisely: an initiative of the ABIM Foundation, American Society of Clinical Oncology, retrieved August 14, 2012<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  44. 44.0 44.1 Lua error in Module:Citation/CS1/Identifiers at line 47: attempt to index field 'wikibase' (a nil value).
  45. "Palliative Care: It's for Caregivers Too, Says Study". Retrieved 2014-08-21.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  46. Heath JA, Clarke NE, Donath SM, McCarthy M, Anderson VA, Wolfe J (2010). "Symptoms and suffering at the end of life in children with cancer: an Australian perspective". Med J Aust. 192 (2): 71–5. PMID 20078405. <templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  47. Lua error in Module:Citation/CS1/Identifiers at line 47: attempt to index field 'wikibase' (a nil value).
  48. Lua error in Module:Citation/CS1/Identifiers at line 47: attempt to index field 'wikibase' (a nil value).
  49. Lua error in Module:Citation/CS1/Identifiers at line 47: attempt to index field 'wikibase' (a nil value).
  50. "Providing Palliative Care to Family Caregivers Throughout the Bone Marrow Transplantation Trajectory". Retrieved 2014-08-21.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  51. [1] Data from the USA 1999–2006, All Races, Both Sexes: Altekruse SF, Kosary CL, Krapcho M, et al (eds). SEER Cancer Statistics Review, 1975–2007, National Cancer Institute. Bethesda, MD, http://seer.cancer.gov/csr/1975_2007/, based on November 2009 SEER data submission, posted to the SEER web site, 2010.
  52. "WHO Disease and injury country estimates". World Health Organization. 2009. Retrieved Nov 11, 2009.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  53. Horner MJ, Ries LAG, Krapcho M, Neyman N, et al. (eds). "SEER Cancer Statistics Review, 1975–2006". Surveillance Epidemiology and End Results (SEER). Bethesda, MD: National Cancer Institute. Retrieved 3 November 2009. Table 1.4: Age-Adjusted SEER Incidence and U.S. Death Rates and 5-Year Relative Survival Rates By Primary Cancer Site, Sex and Time Period <templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  54. Lua error in Module:Citation/CS1/Identifiers at line 47: attempt to index field 'wikibase' (a nil value).
  55. Hellman, Samuel; Mauch, P.M. Ed. (1999). Hodgkin's Disease. Chapter 1: Lippincott Williams & Wilkins. p. 5. ISBN 0-7817-1502-4.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  56. http://www.clinicaltrials.gov/ct2/results?term=lymphoma
  57. "Understanding Clinical Trials for Blood Cancers" (pdf). The Leukemia & Lymphoma Society. Leukemia and Lymphoma Society. Retrieved 19 May 2010.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  58. 58.0 58.1 Lua error in Module:Citation/CS1/Identifiers at line 47: attempt to index field 'wikibase' (a nil value).

External links