Protocol applies to all malignant tumors of the
thyroid gland
except lymphomas.
Procedures
• Cytology
• Total Thyroidectomy
with/without Lymph Node Dissection
This protocol is intended to assist pathologists in
providing clinically useful and relevant information as a result of the
examination of surgical specimens. Use of this protocol is intended to be
entirely voluntary. If equally valid protocols or similar documents are
applicable, the pathologist is, of course, free to follow those authorities.
Indeed, the ultimate judgment regarding the propriety of any specific procedure
must be made by the physician in light of the individual circumstances
presented by a specific patient or specimen.
It should be understood that adherence to this
protocol will not guarantee a successful result. Nevertheless, pathologists are
urged to familiarize themselves with the document. Where a physician chooses to
deviate from the protocol based on the circumstances of a particular patient or
specimen, the physician is advised to make a contemporaneous written notation
of the reason for the procedure followed.
The College recognizes that this document may be
used by hospitals, attorneys, managed care organizations, insurance carriers,
and other payers. However, the document was developed solely as a tool to
assist pathologists in the diagnostic process by providing information that
reflects the state of relevant medical knowledge at the time the protocol was
first published. It was not developed for credentialing, litigation, or
reimbursement purposes. The College cautions that any uses of the protocol for
these purposes involve considerations that are beyond the scope of this
document.
I. Cytologic material back Top Main Page
A. CLINICAL INFORMATION
1. Patient identification
a. Name
b. Identification number
c. Age (birth date)
d. Gender
2. Responsible physician(s)
3. Date of procedure
4. Other clinical information
a. Relevant history
(1) previous treatment
(2) previous head and neck radiation
(3) family history of thyroid disease
b. Relevant findings
(1) euthyroid, hypo- or hyperthyroid, compensated
euthyroid
(2) single or multiple nodules
(3) radiologic studies (e.g. thyroid scan,
ultrasound results)
(4) laboratory findings (e.g. thyroid studies,
antibodies)
c. Clinical diagnosis
d. Procedure (e.g. intraoperative specimen
cytology, FNA)
e. Operative findings
f. Anatomic site(s) of specimen(s)
B. MACROSCOPIC EXAMINATION
1. Specimen
a. Type (e.g. slides, fluid specimen,
fine nedle biopsy,
other)
b. Unfixed/fixed (specify fixative)
c. Number of slides received, if appropriate
d. Results of intraprocedural consultation
2. Material prepared for microscopic evaluation
(e.g. smears, cytospins, filters, cell block)
3. Special studies (specify) (e.g. histochemistry,
immunohistochemistry, morphometry, DNA analysis [specify type])
C. MICROSCOPIC EVALUATION
1. Adequacy of specimen (if unsatifactory for
evaluation, specify reason) (Note A)
2. Tumor, if present
a. Histologic type, if possible (Note
B)
b. Other descriptive characteristics
3. Additional pathologic findings, if present
a. Nodular goiter
b. Adenoma
c. Thyroiditis
d. Other(s)
4. Results/status of special studies
(specify)
5. Comments
a. Correlation with intraprocedural consultation,
as appropriate
b. Correlation with other specimens, as
appropriate
c. Correlation with clinical information, as
appropriate
II. Partial
Thyroidectomy back
Top Main
Page
A. CLINICAL INFORMATION
1. Patient identification
a. Name
b. Identification number
c. Age (birth date)
d. Gender
2. Responsible physician(s)
3. Date of procedure
4. Other clinical information
a. Relevant history
(1) previous treatment
(2) previous head and neck radiation
(3) family history of thyroid disease
b. Relevant findings
(1) euthyroid, hypo- or hyperthyroid, compensated
euthyroid
(2) single or multiple nodules
(3) radiologic studies (e.g. thyroid scan,
ultrasound results)
(4) laboratory findings (e.g. thyroid studies,
antibodies)
c. Procedure (e.g. lobectomy, isthmectomy,
other)
d. Operative findings
e. Anatomic site(s) of specimen(s)
f. Availability of pertinent slides for review
if necessary
B. MACROSCOPIC EXAMINATION
1. Specimen
a. Organ(s)/tissue(s) included
b. Unfixed/fixed (specify fixative)
c. Weight
d. Size (three dimensions)
e. Descriptive characteristics external surface
f. Descriptive characteristics cut surface
(e.g. color, consistency)
g. Orientation (if indicated by surgeon)
h. Nodule(s)/mass(es)
(1) size
(2) number
(3) characteristics (e.g. cystic, calcified,
hemorrhagic)
i. Parathyroid gland(s) (if identified)
j. Results of intraoperative consultation
2. Tumor
a. Location
b. Encapsulated/nonencapsulated
c. Size(s) (Note C)
d. Extracapsular thyroid extension (Note
C)
e. Descriptive characteristics (hemorrhage/necrosis)
f. Distance to margin of resection
3. Margins (as appropriate)
4. Regional lymph nodes (if submitted)
5. Tissue submitted for microscopic evaluation
a. Tumor(s)
b. Mass(es)/nodule(s)
c. Tumor capsule in toto (as appropriate)
d. Noninvolved thyroid
e. Margins (as appropriate)
f. All lymph nodes (if submitted)
g. Parathyroid glands (if identified)
h. Frozen section tissue fragment(s) (unless
saved for special studies)
i. Other tissue(s) (as appropriate)
6. Special studies (specify) (e.g. histochemistry,
immunohistochemistry, morphometry, DNA analysis [specify type])
C. MICROSCOPIC EVALUATION
1. Tumor
a. Histologic type(s) (Note B)
b. Multicentricity, if present
c. Extent of invasion (Note C)
(1) capsular invasion - location and extent
(minimally vs. widely) (Note B)
(2) blood/lymphatic vessel invasion, if present
(note extent: minimally vs. widely) (Note B)
(3) extrathyroid capsular extension (Note
C)
2. Additional pathologic findings, if present
a. Nodular goiter
b. Thyroiditis
c. Therapy related
d. Other(s)
3. Margins (as appropriate)
4. Regional lymph nodes (if submitted)
a. Number
b. Number with metastasis
c. Extranodal extension
5. Other tissues/organs (e.g. parathyroid tissue)
6. Metastasis to other organs/structures (specify
sites)
7. Result/status of special studies (specify)
8. Comments
a. Correlation with intraoperative consultation,
as appropriate
b. Correlation with other specimens, as
appropriate
c. Correlation with clinical information, as
appropriate
III. Total Thyroidectomy
with/without Lymph Node Dissection back
Top Main
Page
A. CLINICAL INFORMATION
1. Patient identification
a. Name
b. Identification number
c. Age (birth date)
d. Gender
2. Responsible physician(s)
3. Date of procedure
4. Other clinical information
a. Relevant history
(1) previous treatment
(2) previous head and neck radiation
(3) family history of thyroid disease
b. Relevant findings
(1) euthyroid, hypo- or hyperthyroid, compensated
euthyroid
(2) single or multiple nodules
(3) radiologic studies (e.g. thyroid scan,
ultrasound results)
(4) laboratory findings (e.g. thyroid studies,
antibodies)
c. Clinical diagnosis
d. Procedure (e.g. thyroidectomy with node
dissection)
e. Operative findings
f. Anatomic site(s) of specimen(s)
B. MACROSCOPIC EXAMINATION
1. Specimen
a. Organ(s)/tissue(s) included
b. Unfixed/fixed (specify fixative)
c. Thyroid gland
(1) weight
(2) size (three dimensions)
(3) symmetry
(4) descriptive characteristics (e.g. color,
consistency)
(5) external surface
(6) cut surface
(7) nodule(s)/mass(es)
i. location
ii. character
iii. calcification
iv. cysts
d. Orientation (if indicated by surgeon)
e. Parathyroid glands (if identified)
f. Description of other tissues
g. Results of intraoperative consultation
2. Tumor
a. Location
b. Descriptive features
c. Size(s) (Note C)
d. Extracapsular thyroid extension (Note
C)
3. Margins (as appropriate)
4. Regional lymph nodes
a. Number
b. Location (if possible)
5. Tissue submitted for microscopic evaluation
a. Tumor(s)
b. Mass(es)/nodule(s)
c. Tumor capsule in toto, as appropriate
d. Noninvoloved thyroid
e. Margins
f. All lymph nodes, if submitted
g. Other lesions
h. Parathyroid tissue (if identified)
i. Frozen section tissue fragment(s) (unless
saved for special studies)
j. Other tissue(s) (specify)
6. Special studies (specify) (e.g. histochemistry,
immunohistochemistry, morphometry, DNA analysis [specify type])
C. MICROSCOPIC EVALUATION
1. Tumor
a. Histologic type(s) (Note B)
b. Multicentricity, if present
c. Location(s)
d. Extent of invasion (Note C)
(1) capsular invasion - location and extent
(minimally vs. widely) (Note B)
(2) blood/lymphatic vessel invasion, if present
(note extent:minimally vs. widely) (Note B)
(3) extrathyroid capsular extension (Note
C)
(4) Invasion of tissue(s) adjacent to thyroid
(specify)
2. Margin(s) (as appropriate)
3. Lymph nodes
a. Number
b. Number involved by tumor
(1) location, if possible
(2) extranodal extension, if present
4. Additional pathologic findings, if present
a. Nodular goiter
b. Thyroiditis
c. Therapy-related changes
d. Nodules/benign tumors
e. Other(s)
5. Other tissues/organs (e.g. parathyroid tissue)
6. Results/status of special studies (specify)
7. Distant metastasis (specify site)
8. Comments
a. Correlation with intraoperative consultation, as appropriate
b. Correlation with other specimens, as
appropriate
c. Correlation with clinical information, as
appropriate
EXPLANATORY NOTES
A. Specimen
Adequacy back Top Main Page
Evaluation of adequacy should be based on
correlation with clinical history, quality and quantity of material aspirated,
and quality of smears. Most malignant tumors, other than follicular carcinomas,
can be recognized on fine needle aspirate if adequately sampled. Guidelines for
FNA of the thyroid have been published.(1)
Guidelines for the Microscopic Evaluation of
Specimen Adequacy(1)
a: If malignant cells, irrespective of the number, are identified in
an aspirate, it should be considered satisfactory. If too few malignant cells
are present for a definitive diagnosis, a “suspicious” diagnosis or a repeat
aspiration may be suggested.
b: The
report should contain a qualifier stating that the interpretation is limited by
the paucity of follicular cells.
c: Occasionally,
a cystic papillary carcinoma may present a similar pattern. Check for residual
solid areas, and re-aspirate if palpable. The risk of malignancy is higher in
large (>4 cm), hemorrhagic cysts and in cysts that recur rapidly or
repeatedly.
B. Histologic
Type back Top Main Page
The histologic classification published by the World
Health Organization (WHO) is recommended by the protocol and shown below.(2,3)
WHO Classification of Carcinoma of the Thyroid
• Follicular
carcinoma
• Papillary
carcinoma
• Medullary
carcinoma
• Undifferentiated
(anaplastic) carcinoma
• Others
The diagnosis of follicular carcinoma or Hürthle
cell carcinoma depends on the identification of capsular and/or blood vessel
invasion. Blood vessels should be of
venous caliber and be located outside the tumor, within, or immediately outside
the capsule. Encapsulated follicular tumors with vascular invasion have
potential for metastasis.(4)
Tumor cells should be attached to the vessel wall and protrude into the
lumen. Encapsulated follicular tumors
with invasion of the capsule may have potential for metastasis, although this
is still controversial.
“Minimally invasive” follicular carcinoma refers to
lesions with no vascular invasion. “Angioaggressive” follicular carcinoma
refers to those tumors in which vascular invasion is identified. “Widely
invasive” follicular and Hürthle cell carcinomas are those tumors with grossly
apparent invasion of thyroid and/or soft tissue.
C. TNM and Stage Groupings back
Top Main
Page
According to the American Joint Committee on
Cancer (AJCC) and the International Union Against Cancer (UICC), staging of
thyroid cancer depends primarily on the histologic type.(5) Thus there are specific TNM stage groupings
for papillary and follicular carcinomas that are stratified by age, and
separate stage groupings not stratified by age for medullary carcinomas and
undifferentiated carcinomas. Hurthle cell tumors are staged the same as
follicular carcinomas. Undifferentiated or anaplastic carcinomas are always
assigned stage IV. Age is not a prognostically important consideration for
medullary or undifferentiated carcinomas.
Tumor size and lymph node status are also considered in the TNM
classification.
With multifocal tumors, the largest one is used
for classification. The lymph nodes must be specifically identified to classify
regional node involvement.
Primary
Tumor (T)*
TX Primary
tumor cannot be assessed
T0 No evidence of primary tumor
T1 Tumor
1 cm or less in greatest dimension limited to the thyroid
T2 Tumor
> 1 cm but not more than 4 cm in greatest dimension limited to the thyroid
T3 Tumor
more than 4 cm in greatest dimension limited to the thyroid
T4 Tumor
of any size extending beyond the thyroid capsule
By AJCC/UICC convention, the designation “T”
refers to a primary tumor that has not been previously treated. The symbol “p” refers
to the pathologic classification of the TNM, as opposed to the clinical
classification and is based on gross and microscopic examination. pT entails a resection of the primary tumor
or biopsy adequate to evaluate the highest pT category; pN entails removal of
nodes adequate to validate lymph node metastasis; and pM implies microscopic
examination of distant lesions.
Clinical classification (cTNM) is usually carried out by the referring
physician before treatment during initial evaluation of the patient or when
pathologic classification is not possible.
Tumor
Remaining in the Patient
Tumor remaining in a patient after therapy with
curative intent (e.g., surgical resection for cure) is categorized by a system
known as R classification, shown below.
RX Presence
of residual tumor cannot be assessed
R0 No
residual tumor
R1 Microscopic
residual tumor
R2 Macroscopic
residual tumor.
For the surgeon, the R classification may be
useful to indicate the known or assumed status of the completeness of a
surgical excision. For the pathologist,
the R classification is relevant to the status of the margins of a surgical
resection specimen. That is, tumor
involving the resection margin on pathologic examination may be assumed to
correspond to residual tumor in the patient and may be classified as
macroscopic or microscopic according to the findings at the specimen margin(s).
Tumor
Remaining in a Specimen
In contrast, tumor remaining in a resection
specimen from a patient who has undergone previous (neoadjuvant) treatment of
any type (radiation therapy alone, chemotherapy therapy alone, or any combined
modality treatment) is codified by the TNM using a prescript “y” (e.g.,
ypT1). Thus, yTNM indicates the
post-treatment status of the tumor. For
many neoadjuvant therapies, the classification of residual disease may be a
strong predictor of postoperative outcome.
In addition, the ypTNM classification provides a standardized framework
for the collection of data needed to accurately evaluate new neoadjuvant therapies.
Locally
Recurrent Tumor
In contrast to “residual” tumor, classification
of a tumor as “recurrent” requires a documented disease-free interval after
definitive therapy. Recurrent tumor may
also be classified according to the TNM categories, but the prefix “r” (e.g.,
rpT1) is used to indicate the recurrent status of the tumor.
Regional
Lymph Nodes (N)
NX Regional
nodes cannot be assessed
N0 No
regional lymph node metastasis
N1a Metastasis
in ipsilateral cervical lymph node(s)
N1b Metastasis
in bilateral, midline, or contralateral cervical or mediastinal lymph node(s)
Distant
Metastasis (M)
MX Distant
metastasis cannot be assessed
M0 No
distant metastasis
M1 Distant
metastasis
Stage
Groupings
Papillary
or Follicular Carcinoma
Under
45
Years of Age 45 Years or Older
Stage I Any
T Any N M0 T1 N0 M0
Stage II Any
T Any N M1 T2 N0 M0
T3 N0 M0
Stage III T4 N0 M0
Any
T N1 M0
Stage IV Any
T Any N M1
Medullary
Carcinoma (Any age)
Stage I T1 N0 M0
Stage II T2 N0 M0
T3 N0 M0
T4 N0 M0
Stage III Any
T N1 M0
Stage IV Any
T Any N M1
Undifferentiated
Carcinoma (all cases - stage IV)
Stage IV Any
T Any N Any
M
For medullary carcinomas, the stage of disease
and postsurgical serum calcitonin levels are the most useful prognostic
factors.(3)
1. Guidelines
of the Papanicolaou Society of Cytopathology for the examination of fine-needle
aspiration specimens from thyroid nodules. Mod Pathol. 1996;9:710-715.
2. Hedinger
C, Williams ED, Sobin LH. Histological Typing of Thyroid Tumours. International
Histological Classification of Tumours, World Health Organization. 2nd ed.
Berlin: Springer-Verlag; 1988.
3. Hedinger
C, Williams ED, Sobin LH. The WHO histological classification of thyroid
tumors: A commentary on the second edition. Cancer. 1989;63:908-911.
4. Franssila
KO, Ackerman LV, Brown CL, Hedinger CE. Follicular carcinoma. Semin Diagn
Pathol. 1986;2:101-122.
5. Fleming
ID, Cooper JS, Henson DE, et al. eds. AJCC Manual for Staging of Cancer. 5th
ed. Philadelphia, PA: Lippincott Raven; 1997.
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Author:
Diane Sneed, MD
©2000. College of American Pathologists
(CAP). All rights reserved. None of the contents of this publication may be
reproduced, stored in a retrieval system or transmitted in any form or by any
means (electronic, mechanical, photocopying, recording, or otherwise) without
prior written permission of the publisher.
Expires
as CAP policy in May 2001. A year
prior, the protocol will be reviewed and updated.
Contributors: back Top Main Page
CAP
Cancer Committee; Virginia A. Livolsi, MD; Michael Cibull, MD; Edward Paloyan,
MD; Henry Travers, MD