Conflict of Interest Disclosure Member of the IQMH Cytopathology - - PDF document

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Conflict of Interest Disclosure Member of the IQMH Cytopathology - - PDF document

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2019/10/25 Conflict of Interest Disclosure Member of the IQMH Cytopathology Scientific Committee A Pot-Pourri of Pitfalls in Non-GYN Cytopathology Cady Zeman-Pocrnich October 26, 2019 Objectives Outline After this session on Non-GYN

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2019/10/25 1

A Pot-Pourri of Pitfalls in Non-GYN Cytopathology

Cady Zeman-Pocrnich October 26, 2019

Conflict of Interest Disclosure

  • Member of the IQMH Cytopathology Scientific

Committee

Objectives

  • After this session on Non-GYN pitfalls,

participants should be able to:

  • Appropriately classify lesions from a variety of

Non-GYN sites by correctly applying morphological criteria, ancillary study criteria, and clues from the clinical history;

  • Reflect on diagnostic misses and near misses in

Non-GYN cytopathology

Outline

Pitfalls I have encountered in the cytopathological diagnosis of:

  • Neuroendocrine Lesions
  • Salivary Gland Tumours
  • Thyroid Nodules

Outline

Pitfalls I have encountered in the cytopathological diagnosis of:

  • Neuroendocrine Lesions
  • Salivary Gland Tumours
  • Thyroid Nodules
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2019/10/25 2

Diagnosis? Pitfall?

Pitfalls in the Cytopathological Dx of Neuroendocrine Lesions

False Negative

Missing Small Cell CA

Pitfalls in the Cytopathological Dx of Neuroendocrine Lesions

False Negative

Missing Small Cell CA

  • Especially on BrBrush/BrWash/BAL
  • Relatively few malignant cells, single cells > clusters
  • Malignant cells misinterpreted as lymphocytes
  • Usually LBC

Pitfalls in the Cytopathological Dx of Neuroendocrine Lesions

False Negative

Missing Small Cell CA

  • Especially on BrBrush/BrWash/BAL
  • Relatively few malignant cells, single cells > clusters
  • Malignant cells misinterpreted as lymphocytes
  • Usually LBC

Small Cell CA on CS Small Cell CA on LBC

Single cells & large tight clusters Single cells & small loose clusters Tight nuclear molding Loose nuclear molding Long strands of nuclear material Nuclear elongation & few tangles Scant cytoplasm Thin rims of cytoplasm Necrosis = obvious Necrosis = subtle

Small Cell CA on CS vs LBC

Single Cells & Large Tight Clusters Single Cells & Small Loose Clusters

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2019/10/25 3

Small Cell CA on CS vs LBC

Tight Nuclear Molding Loose Nuclear Molding

Small Cell CA on CS vs LBC

Long Strands of Nuclear Material Nuclear Elongation & Few Tangles

Small Cell CA on CS vs LBC

Scant Cytoplasm Thin Rims of Cytoplasm

Small Cell CA on CS vs LBC

Abundant Necrosis Droplets of Amorphous Material w/ Apoptotic Bodies

  • Pay attention to clusters
  • Before dismissing as a

“lymphocyte,” consider size & shape

  • Be aware that the classical

cytomorphological features of small cell CA as seen on CS are not as well developed on LBC preps How can this pitfall be avoided?

Pitfalls in the Cytopathological Dx of Neuroendocrine Lesions

False Negative

Missing Small Cell CA

False Positive

Overcalling Carcinoid Tumour as Small Cell CA

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2019/10/25 4 Pitfalls in the Cytopathological Dx of Neuroendocrine Lesions

False Negative

Missing Small Cell CA

False Positive

Overcalling Carcinoid Tumour as Small Cell CA

Pitfalls in the Cytopathological Dx of Neuroendocrine Lesions

False Negative

Missing Small Cell CA

False Positive

Overcalling Carcinoid Tumour as Small Cell CA

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Cancer Cytopathology, Volume: 117, Issue: 1, Pages: 51-56 First published: 29 January 2009, DOI: (10.1002/cncy.20007)

  • Single cells & cells at edges of

clusters appear bland and have ample cytoplasm

  • Absence of necrosis, apoptotic

bodies, and mitotic figures

  • Clinical information
  • Cell block & Ki67

How can this pitfall be avoided? CB Ki67

Pitfalls in the Cytopathological Dx of Neuroendocrine Lesions

False Negative False Positive Misclassification

  • HGNECa ↔ PDAC
  • HGNECa ↔ PDSqCC
  • HGNECa ↔ Lymphoma
  • HGNECa ↔ Sarcoma
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Cancer Cytopathology, Volume: 117, Issue: 1, Pages: 51-56 First published: 29 January 2009, DOI: (10.1002/cncy.20007)

Small Cell CA Lymphoma Ewing’s Sarcoma PD Adenoca, CRC origin Basaloid SqCC How can this pitfall be avoided?

  • If you are going to call small cell

CA based on cytomorphological features alone, the cytomorphological features must be absolutely perfect

  • Immunostudies
  • Second opinion for any case

where the Ddx is small cell vs

  • ther
  • Clinical information

Outline

Pitfalls I have encountered in the cytopathological diagnosis of:

  • Neuroendocrine Lesions
  • Salivary Gland Tumours
  • Thyroid Nodules
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Outline

Pitfalls I have encountered in the cytopathological diagnosis of:

  • Neuroendocrine Lesions
  • Salivary Gland Tumours
  • Thyroid Nodules

Diagnosis? Pitfall?

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2019/10/25 8 Pitfalls in the Cytopathological Dx of Salivary Gland Tumours

False Negative False Positive Misclassification

  • Calling something WT when it’s not

Mucoepidermoid CA

Pitfalls in the Cytopathological Dx of Salivary Gland Tumours

False Negative False Positive Misclassification

  • Calling something WT when it’s not
  • Mucoepidermoid CA
  • Acinic cell CA

CC + Lymphocytes + “oncocytes” Oncocytes in WT “Oncocytes” in MucoEpCA “Oncocytes” in Acinic Cell CA

Pitfalls in the Cytopathological Dx of Salivary Gland Tumours

False Negative False Positive Misclassification

  • Calling something WT when it’s not
  • Mucoepidermoid CA
  • Acinic cell CA
  • Calling something PA when it’s not
  • AdCyCa & other basaloid neoplasms
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PA Stroma AdCyCa Stroma Our Case = Desmoplasia!

Our Case – not a PA!

Plasmacytoid Contour = Irregular “fuzzy” border

PA

  • Naked nuclei
  • Not plasmacytoid

Contour = Tight, rounded

Pitfalls in the Cytopathological Dx of Salivary Gland Tumours

False Negative False Positive Misclassification

  • Not common (in our lab) due to use of diagnostic

categories

  • Beware acceptable atypia in a PA – stay at LP
  • Beware of metaplasias (squamous, mucinous)
  • Beware of repair

Pitfalls in the Cytopathological Dx of Salivary Gland Tumours

False Negative False Positive Misclassification

  • BN ↔ LPN
  • BN ↔ Metastatic CA
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Outline

Pitfalls I have encountered in the cytopathological diagnosis of:

  • Neuroendocrine Lesions
  • Salivary Gland Tumours
  • Thyroid Nodules

Outline

Pitfalls I have encountered in the cytopathological diagnosis of:

  • Neuroendocrine Lesions
  • Salivary Gland Tumours
  • Thyroid Nodules

Special Acknowledgement: Dr. M. Weir

Pitfalls in the Cytopathological Dx of Thyroid Nodules

Architecture Pitfalls Atypia Pitfalls

Undercalling Small Follicle Pattern Overcalling Small Follicle Pattern Undercalling Atypia Overcalling Atypia

Pitfalls in the Cytopathological Dx of Thyroid Nodules

Architecture Pitfalls Atypia Pitfalls

Undercalling Small Follicle Pattern Overcalling Small Follicle Pattern Undercalling Atypia Overcalling Atypia

Pitfalls in the Cytopathological Dx of Thyroid Nodules

Architecture Pitfalls Atypia Pitfalls

Undercalling Small Follicle Pattern Overcalling Small Follicle Pattern Undercalling Atypia Overcalling Atypia

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Before classifying as FN/HCN…

  • 1. Is there chronic thyroiditis?
  • 2. Is there fragmentation?
  • 3. Is evaluation of architecture limited due to blood clot?
  • 4. Could this be parathyroid?

Before classifying as FN/HCN…

  • 1. Is there chronic thyroiditis?
  • 2. Is there fragmentation?
  • 3. Is evaluation of architecture limited due to blood clot?
  • 4. Could this be parathyroid?

Chronic thyroiditis is easy to recognize when it looks like this… Chronic thyroiditis is harder to recognize when it looks like this… Or this… Or this…

Lymphoid tangles & fibrosis Lymphoid aggregates “Sticky follicles” Not true microfollicles!

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Before classifying as FN/HCN…

  • 1. Is there chronic thyroiditis?
  • 2. Is there fragmentation?
  • 3. Is evaluation of architecture limited due to blood clot?
  • 4. Could this be parathyroid?

All images: Dr. M. Weir All images: Dr. M. Weir All images: Dr. M. Weir What to do if fragmented groups are the predominant finding?

  • If very low cellularity

insufficient

  • If cellularity meets adequacy

criteria FLUS/HCL Before classifying as FN/HCN…

  • 1. Is there chronic thyroiditis?
  • 2. Is there fragmentation?
  • 3. Is evaluation of architecture limited due to blood clot?
  • 4. Could this be parathyroid?
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Before classifying as FN/HCN…

  • 1. Is there chronic thyroiditis?
  • 2. Is there fragmentation?
  • 3. Is evaluation of architecture limited due to blood clot?
  • 4. Could this be parathyroid?
  • Microfollicles
  • +/- Colloid-like material
  • Tiny cuboidal cells, very uniform
  • Lateral/unusual location
  • Prior thyroidectomy
  • Hypercalcemia

Images: Dr. M. Weir Parathyroid Hormone IHC

Pitfalls in the Cytopathological Dx of Thyroid Nodules

Architecture Pitfalls Atypia Pitfalls

Undercalling Small Follicle Pattern Overcalling Small Follicle Pattern Undercalling Atypia Overcalling Atypia

Increase atypia threshold if…

  • 1. Chronic thyroiditis
  • 2. Cyst repair
  • 3. Hurthle cells

Respect atypia, but… Increase atypia threshold if…

  • 1. Chronic thyroiditis
  • 2. Cyst repair
  • 3. Hurthle cells

Respect atypia, but…

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2019/10/25 14

Increase atypia threshold if…

  • 1. Chronic thyroiditis
  • 2. Cyst repair
  • 3. Hurthle cells

Respect atypia, but…

Pap Society Bethesda Atlas

Increase atypia threshold if…

  • 1. Chronic thyroiditis
  • 2. Cyst repair
  • 3. Hurthle cells

Respect atypia, but… Image: Dr. M. Weir

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2019/10/25 15 Pitfalls in the Cytopathological Dx of Thyroid Nodules

Architecture Pitfalls Atypia Pitfalls

Undercalling Small Follicle Pattern Overcalling Small Follicle Pattern Undercalling Atypia Overcalling Atypia

Outline

Pitfalls I have encountered in the cytopathological diagnosis of:

  • Neuroendocrine Lesions
  • Salivary Gland Tumours
  • Thyroid Nodules

Conclusions

  • Neuroendocrine Pitfalls
  • Small cell CA can be easily missed be aware of morphological

criteria on LBC preparations

  • Carcinoid tumour can be misdiagnosed as small cell awaremess of

morphological criteria, clinical parameters, use of Ki67

  • Small cell CA is a morphological diagnosis, BUT beware of mimics,

use ancillary studies & 2nd opinions as necesssary

  • Salivary Gland Pitfalls
  • Avoid FN strict criteria for a definitive diagnosis of WT or PA
  • Avoid FP  diagnostic categories
  • Misclassification lymphomas, small cell CA, metastatic CA may

mimic BNs

  • Thyroid Pitfalls
  • Before ascribing a microfollicular architecture, consider CT,

fragmentation, blood clot, PT

  • Before flagging nuclear atypia, consider CT, cyst repair, Hurthle cell

changes