Progressive Transformation of Germinal Center (PTGC)

Related Cases: HP-0318

Clinical Futures

  • Commonly in young males

  • Usually asymptomatic as one enlarged lymph node

  • Most commonly cervical and axillary lymph nodes

  • Surgical excision often curative; may recur, usually locally

Microscopic Findings

  • Large nodules, sharply demarcated,  ≥ 2 × secondary follicles

  • Usually associated with background follicular hyperplasia

  • Predominantly small lymphocytes, no L&H cells

  • Germinal center is either totally replaced by small lymphocytes or fragmented with small residual pieces

  • In the hyperplastic follicles without PTGC, there is often an increase in plasma cells

Clinical Significance

  • May precede, coexist, or follow lymphocyte predominant Hodgkin lymphoma (NLPHL) — risk of NLPHL after PTGC is 1-5%

  • Associated with “IgG4-related lymphadenopathy” in 1/3 cases of PTGC = Type IV (PTGC- like), particularly sustained, multifocal involvement with increased plasma cells in the germinal centers

Note

  • For all lymph node with PTGC, IgG4 immunostain is recommended after excluding lymphoma
  • Most cases of LN with PTGC (80%) have increased IgG4+ cells, typically in the hyperplastic follicles, but not in the PTGC follicles

Reference

 

Last update: 10/06/2017