Parathyroid Gland Involvement by Thyroid Cancer: Results from a Large Series of Thyroidectomies Performed in Two Italian University Hospitals and Review of the Literature
Table 2
Epidemiological, clinical, pathological, and prognostic features of patients with parathyroid involvement by thyroid cancer: review of the literature.
Rate of parathyroid involvement in thyroid cancer patients
2.2%
3.9%
1.6%
0.5%
0.4%
Range: 0.4–3.9%
Number of patients enrolled
20
14
30
10
10
84
Sex
14 F, 6 M
10 F, 4 M
Not reported
8 F, 2 M
7 F, 3 M
F to M ratio: 2.3–4 to 1
Mean age (yrs)
52
60.4
Not reported
52.2
55
Range: 52–60.4
Primary tumor histotype
20 PTC
14 PTC
30 PTC
6 PTC 3 FTC 1 ATC
10 PTC
80 out of 84 cancers are PTC
Primary tumor size
>1 cm 14 ≤1 cm 6
2.5 cm (mean)
>1 cm 22 ≤1 cm 8
2.5 cm (mean)
2.4 cm (mean) >1 cm 10
Microcarcinomas are uncommon
Extrathyroid invasion of tissues other than parathyroid
10 yes 10 no
13 yes 1 no
8 yes 22 no
9 yes 1 no
6 Yes 4 no
46 yes 38 no
Lymph node metastases
17 yes 3 no
13 yes 1 no
1 yes 29 no
5 yes 5 no
3 yes 7 no
39 yes 45 no
Distant metastases
1 yes 19 no
2 yes 12 no
0 yes 30 no
2 yes 2 no
0 yes 10 no
5 yes 79 no
Patterns of parathyroid involvement
Pattern A 15 Pattern B 3 Pattern C 2
Pattern A 10 Pattern B 3 Pattern C 1
Not reported
Pattern A + B 9 Pattern C 1
Pattern A 6 Pattern B 1 Pattern A + B 3
Pattern A + B 90–100% Pattern C 0–10%
Stage*
Not reported
I/II 2 III/IV 12
pT3 30/30
I/II 3 III/IV 7
I 2 III 8
—
Recurrence
Not reported
2 yes 12 no
1 yes 29 no
Not reported
0 yes 10 no
Most cases do not recur
10-yr disease free survival rate
Not reported
80.8%
>95%
Not reported
N/A
>80% in the reported cases
ATC: anaplastic thyroid carcinoma; F: female; FTC: follicular thyroid carcinoma; M: male; N/A: not applicable; PTC: papillary thyroid carcinoma; Pattern A: direct invasion by infiltrative growth from the primary thyroid carcinoma to parathyroid; Pattern B: extension of thyroid malignancy into the parathyroid, in which cancer nests are separated from by a pseudocapsule; Pattern C: true thyroid cancer metastasis within the parathyroid, with no evidence of continuity from the primary thyroid tumor; Ref.: reference. *Based on AJCC/International Union against Cancer (AJCC/UICC) classification system [11].
