Unusual Tumors of the Thyroid: Case 4 Theresa Scognamiglio, M.D. - - PowerPoint PPT Presentation

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Unusual Tumors of the Thyroid: Case 4 Theresa Scognamiglio, M.D. - - PowerPoint PPT Presentation

Jan 24, 2024 271 likes •542 views

Unusual Tumors of the Thyroid: Case 4 Theresa Scognamiglio, M.D. Assistant Professor of Pathology Weill Cornell Medicine Case History 44 year old woman who noticed a lump in neck 6 weeks prior to presentation No hoarseness, dysphagia

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SLIDE 1

Unusual Tumors of the Thyroid: Case 4

Theresa Scognamiglio, M.D. Assistant Professor of Pathology Weill Cornell Medicine

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SLIDE 2

Case History

  • 44 year old woman who noticed a lump in neck 6 weeks

prior to presentation

  • No hoarseness, dysphagia
  • Normal thyroid function tests
  • Ultrasound was performed
  • 3.3 x 2.8 x 2.1 cm hypoechoic complex nodule in the

left thyroid lobe

  • Fine needle aspiration was performed
  • Paucicellular with scant spindle cells
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SLIDE 3

Well Circumscribed Solid Firm White Cut Surface

Total Thyroidectomy

1 cm

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SLIDE 4

Prominent Stromal Proliferation

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SLIDE 5

Stromal

Two Distinct Components

Epithelial

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SLIDE 6

Spindle Cells in Fascicles

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SLIDE 7

Thick Collagen Fibers Hypercellular Extravasated RBCs Myxoid

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SLIDE 8

Bland Spindle Cells

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SLIDE 9

Papillary Thyroid Carcinoma

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SLIDE 10

Epithelial Component: Papillary Thyroid Carcinoma

TTF-1 Pax-8

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SLIDE 11

Stromal Component

SMA Pan-Keratin

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SLIDE 12

Immunostains Epithelium Stroma TTF-1 +

  • PAX-8

+

  • CKAE1/AE3

+

  • CK7

+

  • Cam5.2

+

  • EMA

+

  • Beta catenin

+ membranous + nuclear/cytoplasmic SMA

  • +

Desmin

  • Focal +

Summary of IHC

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SLIDE 13

Summary of Findings

  • Spindle cell proliferation

with associated conventional PTC

  • Bland spindle cells
  • Negative for

epithelial markers

  • Negative for thyroid

specific markers

  • Positive for SMA
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SLIDE 14

Papillary Thyroid Carcinoma Membranous Nuclear/Cytoplasmic Stroma

β-Catenin Immunostain

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SLIDE 15

Papillary Thyroid Carcinoma (PTC) with Nodular Fasciitis-Like Stroma (NF)/Fibromatosis-Like Stroma (FM)

FINAL HISTOLOGIC DIAGNOSIS

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SLIDE 16

PTC with NF/FM-Like Stroma is a Rare Variant of PTC

  • Chan et al. 1991
  • <1% of PTC variants
  • <50 cases
  • F>M, 20-82 years
  • Palpable neck mass
  • Dual components
  • Conventional PTC

─BRAF

  • Stroma resembling

nodular fasciitis/fibromatosis

  • Prognosis similar to

conventional PTC

STROMAL COMPONENT USUALLY PREDOMINATES DUAL COMPONENTS

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SLIDE 17

FNA Can Be Diagnostically Challenging

  • Epithelium is often minor

component

  • Increases the risk of false

negative

  • Stromal component may be

misinterpreted

  • Benign, reactive, malignant

spindle cell lesions

Us‐Krasovec et al. Acta Cytologica. 1999; 43: 1101‐4 Yang et al. Arch Pathol Lab Med. 1999; 123: 838‐41

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SLIDE 18

Exact Pathogenesis of the Stromal Component Unknown: Reactive vs Neoplastic

  • Collagen fibers
  • Abundant RER
  • Smooth muscle markers
  • TGF beta
  • Mediates activation
  • f fibroblasts
  • Aberrant nuclear

expression of β-catenin

  • Activating

mutation in CTNNB1 ULTRASTRUCTURE IMMUNOHISTOCHEMISTRY MOLECULAR

PROFILE SIMILAR TO FIBROMATOSIS

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SLIDE 19

Differential Diagnosis of Spindle Cell Lesions in Thyroid

  • PTC with metaplastic spindle cells
  • Diffuse sclerosing variant of PTC

(DSCPTC)

  • Medullary thyroid carcinoma
  • Spindle cell tumor with thymus-like

differentiation (SETTLE)

  • Carcinoma showing thymus-like

differentiation (CASTLE)

  • Anaplastic carcinoma
  • Solitary fibrous tumor
  • Smooth muscle tumors
  • Peripheral nerve sheath tumors
  • Melanoma
  • Reidel thyroiditis
  • Hashimoto thyroiditis,

fibrous variant

  • Post FNA spindle cell

nodules

  • Spindle cell follicular

adenoma

  • Fibromatosis
  • Nodular fasciitis
  • Schwannoma

BENIGN MALIGNANT

Identification of the PTC Component Will Help Narrow the Differential

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SLIDE 20

Differential Diagnosis of Spindle Cell Lesions Arising in Association with PTC

  • PTC with metaplastic spindle cells, spindle cell

variant

  • Diffuse sclerosing variant of papillary thyroid

carcinoma (DSCPTC)

  • Anaplastic carcinoma, spindle cell and paucicellular

variant

  • PTC with NF/SM-like stroma
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SLIDE 21

Differential Diagnosis

PTC NF/FM Reidel Thyroiditis β‐catenin positive Lacks significant inflammation Sclerotic fibrosis Inflammatory infiltrate Phlebitis Lacks neoplasm

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SLIDE 22

Differential Diagnosis

PTC NF/FM Hashimoto Thyroiditis, Fibrous Variant β‐catenin positive Lacks significant inflammation Less cellular More prominent inflammation Follicular atrophy Lacks neoplasm

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SLIDE 23

Differential Diagnosis

PTC NF/FM PTC with Metaplastic Spindle Cells β‐catenin positive TTF-1/Thyroglobulin negative CK negative β‐catenin negative TTF-1/Thyroglobulin positive CK positive

Corrado et al. Endocr Path. 2014; 25:307‐314

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SLIDE 24

Differential Diagnosis

PTC NF/FM DSCPTV β-catenin positive TTF-1/Thyroglobulin negative CK negative Stroma is sclerotic Lymphocytic infiltrate Psammoma bodies

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SLIDE 25

Differential Diagnosis

PTC NF/FM Anaplastic

  • Wenig. Atlas of Head and Neck Pathology. 2008

Lacks significant atypia β-catenin positive TTF-1/Thyroglobulin negative Epithelial markers negative Significant atypia and mitotic figures TTF-1/Thyroglobulin negative Epithelial markers positive

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SLIDE 26

Summary

  • PTC with NF/FM-like stroma is a rare and unusual variant
  • Challenging in FNA and histologic specimens
  • Recognition is important to avoid diagnostic misinterpretation
  • Benign reactive process
  • Aggressive histologic variants
  • Presence of fibroproliferative lesion should prompt adequate

sampling of specimen

  • Stromal proliferation can obscure the epithelial component
  • IHC in combination with morphology can be helpful in making

the correct diagnosis