In situ lymphoid neoplasia

In situ lymphoid neoplasia
SpecialtyHematology, oncology
SymptomsAsymptomatic
ComplicationsMay progress to follicular lymphoma or mantle cell lymphoma; may be associated with the development of certain other lymphoid malignancies
DurationChronic
TypesIn situ follicular lymphoma; in situ mantle cell lymphoma
TreatmentFollow-up tests for the development of follicular or mantle cell lymphoma, or other lymphoid malignancies

In situ lymphoid neoplasia (ISLN, also termed in situ lymphoma) is a precancerous condition newly classified by the World Health Organization in 2016. The Organization recognized two subtypes of ISLN: in situ follicular neoplasia (ISFN) and in situ mantle cell neoplasia (ISMCL).[1] ISFN and ISMCL are pathological accumulations of lymphocytes in the germinal centers and mantle zones, respectively, of the follicles that populate lymphoid organs such as lymph nodes. These lymphocytes are monoclonal (i.e. descendants of a single ancestral cell) B-cells that may develop into follicular (FL) and mantle cell (MCL) lymphomas, respectively.[2]

When used to characterize a neoplasm, in situ has referred to a localized, non-destructive accumulation in a tissue of cells that bear resemblances to the malignant cells of one of the cancers that can develop in this tissue. The in situ accumulations can progress to become the malignancy that their cells resemble. The term, while readily applicable to abnormal cell accumulations in solid tissues such as those of the cervix, has been difficult to apply to lymphatic tissue because many of these tissue's cells normally move through blood and lymphatic vessels to occupy other tissues. Recently, however, monoclonal B-cells with some key characteristics of the malignant B-cells in FL or MCL have been found to accumulate in one or more lymphoid tissues. These accumulations are localized, non-destructive (i.e. not effacing a tissue's normal architecture), premalignant, and therefore now regarded as in situ disorders similar to those in solid tissues.[3]

ISFN[4] and ISMCL[5] are usually indolent, asymptomatic disorders that rarely progress to malignancy. Typically, they are diagnosed based on the findings in lymphoid tissues examined for other reasons. ISLN bear similarities to monoclonal B-cell lymphocytosis (MBL). MLB consists of four subtypes: chronic lymphocytic leukemia/small lymphocyte MBL (i.e. CLL/SLL-MBL), atypical CLL/SLL-MBL, non-CLL/SLL-MBL,[3] and monoclonal B-cell lymphocytosis of the marginal zone (CBL-MZ).[6] These MBL subtypes are indolent, asymptomatic, monoclonal B-cell disorders diagnosed, generally incidentally, by finding the circulation of relatively large numbers of monoclonal B-cells that correspond in type to the malignancies to which they may progress. ISLN differs from MCL in that its B-cells are found mainly in lymphoid tissue, it involves different monoclonal B-cell types, and it usually progresses to a set of different types of lymphoid malignancies.[2][6][7] However, 1) MBL disorders can progress to FL or MCL, 2) small numbers of the B-cells involved in ISFN may circulate in individuals who have or will develop ISFN,[1] and 3) the B-cells in MBL may accumulate in lymphoid tissues.[7]

  1. ^ a b Oishi N, Montes-Moreno S, Feldman AL (January 2018). "In situ neoplasia in lymph node pathology". Seminars in Diagnostic Pathology. 35 (1): 76–83. doi:10.1053/j.semdp.2017.11.001. PMID 29129357.
  2. ^ a b Karube K, Scarfò L, Campo E, Ghia P (February 2014). "Monoclonal B cell lymphocytosis or in situ lymphoma". Seminars in Cancer Biology. 24: 3–14. doi:10.1016/j.semcancer.2013.08.003. PMID 23999128.
  3. ^ a b Choi SM, O'Malley DP (December 2018). "Diagnostically relevant updates to the 2017 WHO classification of lymphoid neoplasms". Annals of Diagnostic Pathology. 37: 67–74. doi:10.1016/j.anndiagpath.2018.09.011. PMID 30308438. S2CID 52963674.
  4. ^ Qu Q, Xuan W, Fan GH (January 2015). "Roles of resolvins in the resolution of acute inflammation". Cell Biology International. 39 (1): 3–22. doi:10.1002/cbin.10345. PMID 25052386. S2CID 10160642.
  5. ^ Ye H, Desai A, Zeng D, Nomie K, Romaguera J, Ahmed M, Wang ML (December 2017). "Smoldering mantle cell lymphoma". Journal of Experimental & Clinical Cancer Research. 36 (1): 185. doi:10.1186/s13046-017-0652-8. PMC 5732450. PMID 29246179.
  6. ^ a b Xochelli A, Oscier D, Stamatopoulos K (2017). "Clonal B-cell lymphocytosis of marginal zone origin". Best Practice & Research. Clinical Haematology. 30 (1–2): 77–83. doi:10.1016/j.beha.2016.08.028. PMID 28288720.
  7. ^ a b Strati P, Shanafelt TD (July 2015). "Monoclonal B-cell lymphocytosis and early-stage chronic lymphocytic leukemia: diagnosis, natural history, and risk stratification". Blood. 126 (4): 454–62. doi:10.1182/blood-2015-02-585059. PMC 4624440. PMID 26065657.