Progressive transformation of germinal centers

Progressive transformation of germinal centers
Diagnosis in short
PTGC. H&E stain.
LM	follicular hyperplasia with focally large germinal centers with a poorly demarcated germinal center (GC)/mantle zone interfaces (as GCs infiltrated by mantle zone lymphocytes), expanded mantle zone
LM DDx	nodular lymphocyte predominant Hodgkin lymphoma, other lymphomas
Site	lymph node
Signs	lymphadenopathy
Symptoms	asymptomatic
Prevalence	very rare
Clin. DDx	lymph node metastasis, lymphoma

Progressive transformation of germinal centers, abbreviated PTGC, is a rare lymph node pathology.

General

• Benign.
• Classically in younger patients.
• Associated with nodular lymphocyte predominant Hodgkin lymphoma (NLPHL); NLPHL found in up to 5% in a 7 year follow-up.

Clinical:

• Asymptomatic lymphadenopathy.

Microscopic

Features:

• Follicular hyperplasia (many follicles).
• Focally large germinal centers with:
  • Poorly demarcated germinal center (GC)/mantle zone interfaces (as GCs infiltrated by mantle zone lymphocytes) -- key feature.
  • Expanded mantle zone.

Images

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  PTGCs - low mag. (WC)

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  PTGCs - intermed. mag. (WC)

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  PTGCs - very low mag. (WC)

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  PTGCs - low mag. (WC)

• 

  PTGCs - intermed. mag. (WC)

See also

• Lymph node pathology.
• Lymph node.
• Haematopathology.

Additional reading

• Hansmann ML, Fellbaum C, Hui PK, Moubayed P (February 1990). "Progressive transformation of germinal centers with and without association to Hodgkin's disease". Am. J. Clin. Pathol. 93 (2): 219–26. PMID 2405631.
• Kojima M, Nakamura S, Motoori T, et al. (April 2003). "Progressive transformation of germinal centers: a clinicopathological study of 42 Japanese patients". Int. J. Surg. Pathol. 11 (2): 101–7. PMID 12754626.