Lymphoma & related disorders

• ICD-10: C83.1 - mantle cell lymphoma (Western Australian Coding Rule: 1215/02 Mantle cell lymphoma in situ [Accessed 11 June 2019])

Contributed by Kyle Bradley, M.D.

• Characteristic translocation t(11;14) IGH-CCND1 results in overexpression of cyclin D1 (Virchows Arch 2016;468:245)

• Lymph node, right axilla, excision:
  • In situ mantle cell neoplasia (see comment)
  • Comment: The H&E stained sections show morphologic features consistent with a benign lymph node with follicular hyperplasia. A cyclin D1 immunohistochemical stain demonstrates cyclin D1 positive cells confined to the inner mantle zones of lymphoid follicles without mantle zone expansion. These findings are consistent with in situ mantle cell neoplasia. In situ mantle cell neoplasia typically follows an indolent course; however, rare cases may progress to overt mantle cell lymphoma.

• Mantle cell lymphoma with mantle zone growth pattern (Semin Diagn Pathol 2018;35:76)
  • Expansion of the mantle zone, complete replacement of the mantle zone or significant extension into the interfollicular region or germinal centers by cyclin D1 positive B cells warrants a diagnosis of mantle cell lymphoma rather than in situ mantle cell neoplasia (Blood 2016;127:2375)
• Reactive follicular hyperplasia (Semin Diagn Pathol 2018;35:76)
  • Reactive follicular hyperplasia lacks cyclin D1 positive cells within the mantle zones (Semin Diagn Pathol 2018;35:76)

In situ mantle cell neoplasia is characterized by which of the following translocations?


1. t(9;22) BCR-ABL1
2. t(11;14) IGH-CCND1
3. t(14;18) BCL2-IGH
4. t(8;14) MYC-IGH

B. The characteristic translocation of in situ mantle cell neoplasia is t(11;14) IGH-CCND1, resulting in overexpression of cyclin D1.

Reference: In situ mantle cell neoplasia

Comment Here

In a lymph node biopsy, which of the following features supports a diagnosis of in situ mantle cell neoplasia?


1. Mantle zones expanded by cyclin D1 positive B cells
2. Cyclin D1 positive B cells extending into the interfollicular region
3. Monoclonal proliferation of BCL2 positive B cells confined to germinal centers
4. Preserved lymphoid architecture

D. In situ mantle cell neoplasia is characterized by cyclin D1 positive B cells restricted to the mantle zone of reactive appearing lymphoid tissue. Lymphoid architecture is preserved. Expansion of the mantle zone, complete replacement of the mantle zone or significant extension into the interfollicular region or germinal center by cyclin D1 positive B cells warrants a diagnosis of mantle cell lymphoma rather than in situ mantle cell neoplasia. A monoclonal proliferation of BCL2 positive B cells confined to germinal centers in a hyperplastic appearing lymphoid follicle is consistent with in situ follicular neoplasia.

Comment Here

Reference: In situ mantle cell neoplasia

Which of the following is true of in situ mantle cell neoplasia?


1. Usually progresses to overt mantle cell lymphoma
2. Characterized by aggressive behavior
3. May be seen in extranodal locations
4. Peripheral blood involvement is not permitted

C. In situ mantle cell neoplasia is a rare finding that is most commonly seen in lymph nodes but may be seen in extranodal locations. Peripheral blood involvement is permitted. It is typically a stable disease with indolent behavior and rare progression to overt mantle cell lymphoma.

Comment Here

Reference: In situ mantle cell neoplasia