Ultrasound Findings of Papillary Thyroid Carcinoma Originating in the Isthmus: Comparison With Lobe-Originating Papillary Thyroid CarcinomaSoo Yeon Hahn1 Boo-Kyung Han Eun Young Ko Jung Hee Shin Eun Sook Ko

Hahn SY, Han BK, Ko EY, Shin

JOURNAL

ClCLERKSHIP DEPARTEMENT OF RADIOLOGYAMBARAWA REGIONAL GENERAL HOSPITAL

Presented by : Meilani Sulaeman1420221145

Supervisor : dr.Novita, Sp.Rad

Ultrasound Findings of Papillary Thyroid Carcinoma Originating in the Isthmus: Comparison With Lobe-Originating

Papillary Thyroid Carcinoma

• Brownish-red, highly vascular gland• Location: ant neck at C5-T1,

overlays 2nd – 4th tracheal rings• Avg width: 12-15 mm• Avg height: 50-60 mm• Avg weight: 25-30 g in adults

Batas lobus:

anterior

posteolateralmedial

M. sternothytoideus

M. sternohyoideus

M. sternocleidormastoideus

V. Jugularis interna

N. vagus

A. Corotis communis

Trakea esofagus

Vascular Anatomy Arteri thyroidea superior Arteri thyroidea inferior Arteri thyroidea IMA

Vena thyroidea superior Vena thyroidea inferior Vena thyroidea media

VASCULARISATIO GLANDULAE THYREOIDEAE CARTILAGO THYREOIDEA. A. CAROTIS EXTERNA A. CAROTIS INTERNA

1. A. THYREOIDEA SUPERIOR CARTILAGO CRICOIDEA ISTHMUS GLD. THYR. GLANDULA THYREOIDEA 2. A. THYREOIDEA INFERIOR 3. A.THYREOIDEA IMA

A. CAROTIS COMM.SIN.TRUNCUS THYREOCERVICALIS A. SUBCLAVIA DEXTRA A. SUBCLAVIA SIN.

A. ANONYMA ( A. INNOMINATA, ARCUS AORTAETRUNCUS BRACHIOCEPHALICA )

04/27/2023 10:17 PM 5

v. Thyroidea inferior

v. Thyroidea suprior

v. Thyroidea medialis

Structure• Under middle layer of deep cervical fascia (pretracheal) thyroid inner

true capsule thin and closely adherent to the gland• capsule extensions within the gland form septae, dividing it into lobes and

lobules• lobules are composed of follicles = structural units of the gland layer

epithelium enclosing a colloid-filled cavity

Fundamentals of Diagnostic Radiology, 3rd Edition

OBJECTIVE• According to previous reports, a small percentage of patients

present with masses confined to the isthmus, and the incidence of papillary thyroid carcinoma (PTC) between 2.5% and 9.2% [1–3]

• However, PTCs arising in the isthmus are more likely to invade adjacent tissues, such as the trachea and strap muscles, than PTCs located in the other parts of the thyroid [1, 2, 4]

• Therefore, the purpose of this study was to analyze the ultrasound features and clinicopathologic characteristics of PTCs originating in the isthmus and to evaluate how these tumors differ from PTCs that originate in the lobes

Materials and Methods

• Patients From the records of 2623 reviewed 58 cases of index tumors diagnosed as classic PTC located in the isthmus after a total thyroidectomy or lobectomy.

• Among the 58 lesions, we excluded • Finally, 48 patients with 48 classic PTCs located in the isthmus were included in the study

group. • As a control group, 96 patients with classic PTC located in a lobe who underwent total

thyroidectomy with bilateral central lymph node dissection during the same period were randomly selected and matched to the study patients with respect to age, sex, and tumor size.

Imaging Methods• Ultrasound and ultrasound-guided fine-needle aspiration

(FNA) were performed using a 7- to 15-MHz linear-array transducer (HDI 5000, Philips Healthcare) or a 5- to 12-MHz linear array transducer (IU22, Philips Healthcare)

• by one of six board-certified radiologists who were aware of the clinical findings.

• All ultrasound-guided FNA there were not any differences in ultrasound-guided FNA techniques for isthmus-originating masses and lobe originating masses.

Data Collection and Analysis • The following ultrasound findings margin, shape, and internal echogenicity of the mass

and the presence of calcifications, cystic changes, and an ultrasound finding suspicious for extrathyroidal extension

• The margin was classified as being either circumscribed or not circumscribed

• The shape was categorized as being wider-than-tall or taller-than-wide.

• Internal echogenicity was classified as hyperechogenicity, isoechogenicity, hypoechogenicity, marked hypoechogenicity, or anechogenicity.

• The presence or absence of calcifications and cystic changes was also evaluated.

• When the malignant mass had capsular abutment of more than 25% of its perimeter on ultrasound, the mass was classified as having ultrasound finding suspicious for extrathyroidal extension [13, 14].

• First, divide the thyroid gland into the isthmus and lobes (Fig. 1) on the transverse scan.

Fig. 1—Ultrasound image of thyroid of 37-year-old woman who was a healthy volunteer. To divide thyroid gland into isthmus and lobe, we defined lateral border of isthmus by drawing two imaginary lines (arrows) perpendicular to skin surface from most lateral borders of trachea.

Fig. 2—51-year-old woman with papillary thyroid carcinoma (PTC) originating in isthmus. A and B, Transverse (A) and longitudinal (B) ultrasound images show 1.2-cm cystic mass with circumscribed margin, wider-than-tall shape, broad abutment to anterior capsule (> 25%), and anterior capsular bulging. Analysis of fine-needle aspiration cytologic examination result revealed PTC. After surgery, diagnosis was PTC arising in

isthmus without lymph node metastasis. According to pathologic report, no extrathyroidal extension was found despite ultrasound finding suspicious for extrathyroidal extension

Results

• The mean age at the time of diagnosis of all 144 patients was 47.6 ± 12.6 (SD) years (range, 28–77 years).

• The female-to-male ratio was 4.3:1.0 (81.3% vs 18.7%, respectively).

• The mean tumor size was 1.2 ± 0.7 cm (range, 0.3–3.7 cm).

RESULTS • According to the clinicopathologic analyses, the incidence of

extrathyroidal extension was higher in the patients with a tumor originating in the isthmus than in the control group (p = 0.026)

• According to the imaging analyses, the tumors originating in the isthmus more frequently had a circumscribed margin (p = 0.030), a wider-than-tall shape (p < 0.001), and the suspicion of extrathyroidal extension (p < 0.001) than those originating from the lobes.

CONCLUSION• The results of this study showed that PTCs originating in the

isthmus were more likely to have extrathyroidal extension than those originating from the lobes.

• Therefore, careful ultrasound evaluation should be performed on masses in the thyroid isthmus even if ultrasound shows a circumscribed mass with a wider-than-tall shape.

Malignant. Longitudinal US image of papillary thyroid carcinoma in 42-year-old woman shows marked hypoechogenicity, spiculated margin, microcalcifications, and taller-than-wide shape.

microcalcifications

Poor margination

hypoechogenity

Benign. Longitudinal US image of benign nodule in 46-year-old woman shows ovoid shape, isoechogenicity, and smooth margin.

isoechogenity Smooth margin

TERIMA KASIH

Five categories for US diagnosis of solid thyroid nodules

• D, Malignant features in a 45-year-old woman. A longitudinal sonogram of a papillary thyroid carcinoma in the left lobe shows an eccentric configuration with an acute angle (arrows), macrolobulation, microcalcifications, and hypoechogenicity.

A, Benign features in a 60-year-old woman. A longitudinal sonogram of nodular hyperplasia in the left lobe shows a concentric configuration with a centrally located cystic component, a smooth free margin, an ovoid shape, and isoechogenicity.

B. Suspicious for malignancy. Longitudinal US image of papillary thyroid carcinoma in 42-year-old woman shows marked hypoechogenicity, smooth margin, and ovoid shape.

C. Borderline. Transverse US image of nodular hyperplasia in 60-year-old woman shows macrocalcification in peripheral portion of nodule. Patient underwent right lobectomy of thyroid, despite benign cytology upon US-guided fine-needle aspiration, for pathologic confirmation.

D. Probably benign. Longitudinal US image of benign nodule in 57-year-old woman shows isoechogenicity and smooth margin.

B, Probably benign in a 50-year-old woman. A transverse sonogram of nodular hyperplasia in the left lobe shows an eccentric configuration with a blunt angle between the solid component and the wall (arrows), a smooth free margin, and isoechogenicity.

C, Suspicious for malignancy in a 28-year-old woman. A longitudinal sonogram of a papillary thyroid carcinoma in the left lobe shows an eccentric configuration with an acute angle between the solid component and the wall (arrows), a microlobulation, and isoechogenicity.

Lymphatics

• defined the lateral border of the isthmus by drawing two imaginary lines perpendicular to the surface of the skin from the most lateral points of the trachea

• If the center of the thyroid mass was located between these two imaginary lines, we classified it as a mass originating in the isthmus even if its margin crossed these two imaginary lines

• Taller than-wide shape was defined as a mass that was greater in its anteroposterior dimension than its transverse dimension

• When the echogenicity of the mass was similar to that of the thyroid parenchyma, we classified it as isoechogenicity. Marked hypoechogenicity was defined as decreased echogenicity compared with the surrounding strap muscle

1. Bagaimana kita tau bahwa tiroid tersebut hipoekogenik atau sebaliknya, adakah perbandingannya?

2. Adakah kelebihan dari penelitian ini?3. Tadi dijelaskan histologi dari kelenjar tiroid. Secara

histologis karsinoma tiroid papiler itu berasal dari sel apa?

4. Mengapa yang tidak menjalani operasi dieksklusikan?5. Adakah perbedaan gambaran USG dari tumor tiroid

yang benign dan yg malignan?