This document discusses the approach to lymph node cytology. It begins by outlining the spectrum of conditions lymph node cytology can identify, including benign, malignant, metastatic, and lymphoma. It emphasizes the importance of clinical information and microscopy, and the role of ancillary tests. The key cytomorphologic features used to examine lymph node fine needle aspirations are described. Specific cytologic patterns are discussed, including tissue fragments, polymorphous and monotonous small/large/intermediate cells, and dispersed single cells. Several case examples are provided and diagnostic approaches for different cytologic patterns are outlined.

2. Approach to Lymph node Cytology
Fereshteh Ameli

3. Approach to Lymph node Cytology
Spectrum of conditions:
- Benign
- Malignant
- Metastatic
- Lymphoma
- Not a lymph node

4. • Clinical Information
• Microscopy
• Ancillary tests
Approach to Lymph node Cytology

5. Clinical Information
• Age, symptoms, site, size, time of onset,
imaging (US)
• Past and current medical history
• Basic serology (ESR, LDH, ToRCH complex,
ANA, others)

6. Key cytomorphologic features used to
examine lymph node FNA

7. Microscopy
• Low power:
– Tissue architecture
• Tissue fragments /cohesive cell groups
• Dispersed cells
– Background material (cyst fluid/necrosis)
• High power:
• Lymphoid or not?
• Monotonous or polymorphous?
• Cell size: small/ large/ intermediate?

8. Residents of a Normal Lymph node

9. Lymph node cytologic pattern

10. Small Large
Intermediate

12. Ancillary tests
• Infections: Microbiology culture
• Malignancy
– Metastatic: Cell block
– Suspect lymphoma: Cell block/ Flow cytometry

13. Case 1
Cervical LN FNA: A 5 y/o boy with a
history of chronic otitis media

22. FNA Diagnosis:
• Negative for malignant cells, features of
benign reactive LN
• Further investigation is warranted if
unexplained lymphadenopathy persists or
progresses.

23. Lymphoid tissue fragments vs
Metastatic ca

24. Tissue Fragments: DDX

25. Granulomatous LN

26. Granulomatous LN

28. Case 2
A 65 y/o woman with intraparotid LN

36. Age 65

37. Dx:
Atypical lymphoid population,
suspicious for non-hodgkin lymphoma,
recommend excision
Follow up- histo: Low grade follicular lymphoma

38. Polymorphous pattern
• Reactive lymph node
• Low grade lymphoma
– Marginal zone lymphoma
– Low grade follicular lymphoma
– NLPHL
– T cell lymphoma
False Negatives

39. Polymorphous pattern

42. Polymorphous pattern

45. A 55 y/o woman with cervical
lymphadenopathy
Case 3

51. Dx:
Positive for malignancy, suspicious for
high grade non-hodgkin lymphoma,
recommend tissue evaluation
Follow up- histo: Diffuse large B cell lymphoma

52. Predominant large cell pattern

53. Burkitt's lymphoma

54. A 75 y/o man with extensive
lymphadenopathy
Case 4

60. Dx:
Suspicious for malignancy, suggestive of
a low grade non-hodgkin lymphoma,
recommend tissue evaluation
Follow up- histo: CLL/SLL

61. Predominant small cell pattern

62. A 25 y/o man with cervical LN
Case 5

67. Dx:
Suspicious for Hodgkin lymphoma,
recommend tissue evaluation
Follow up- histo: Classic Hodgkin lymphoma

68. Pleomorphic cell pattern

70. DISPERSED CELLS: DDx

73. Small cell carcinoma

75. Pattern based approach
• Pattern 1: Cohesive tissue fragments
– Lymphoid aggregates
• Benign-germinal centers
• Malignant: FL, Anaplastic large cell lymphoma
– Non-lymphoid
• Metastasis
• Granulomatous LN
– Not a Lymph node

76. Pattern based approach
• Pattern 2: Predominantly single cells
– Lymphoid:
• Mixed population: Reactive LN, MZL, NLPHL, low grade FL
• Monotonous: Lymphoma
• Scattered large cells: HL,ALCL, TCRBCL
– Non-Lymphoid:
• Metastases: (NPC, small cell ca, melanoma)

77. False positive:
-EBV LN
- Kikuchi

78. :
Acknowledgement