Fig. 1Parathyroid adenoma. Cells are positive for chromogranin A (A) and negative for thyroid transcription factor-1 (B).
Fig. 2Representative cytological features of a parathyroid lesion. (A) A loose cluster demonstrates a round configuration. (B) A tight cluster shows overlapping nuclei. (C) A papillary pattern has a fibrovascular core with parathyroid cells arranged in a vascular network. (D) Smears from an aspirated intrathyroidal parathyroid lesion show a lymphoid pattern (A-D, Papanicolaou stain).
Fig. 3Representative nuclear features of a parathyroid lesion. (A) Nuclei are uniform and round to oval with stippled chromatin. A few cells show a well-defined cell border and an intercellular window. (B) Eccentric nuclei and anisokaryosis with a few atypical nuclei in the periphery (arrow). (C) An intranuclear pseudoinclusion has a distinct boundary resembling a shape drawn with a pencil (arrow) (A-C, Papanicolaou stain).
Table 1.Clinicopathologic characteristics of the 25 cases
Feature |
No. (%) |
Gender |
|
Male |
6 (24) |
Female |
19 (76) |
Mean age (yr) |
51 |
Mass size in mean (cm) |
1.9 |
Serum PTH |
|
Normal |
9 (36) |
Elevated |
13 (52) |
Unknown |
3 (12) |
Location |
|
Posterior to thyroid gland |
9 (36) |
Inferior to thyroid gland |
7 (28) |
Intrathyroidal |
6 (24) |
Paratracheal |
3 (12) |
Clinicoradiologic impression |
|
Incidentaloma |
11 (44) |
Primary hyperparathyroidism |
8 (32) |
Parathyroid lesion |
4 (16) |
Metastatic papillary thyroid carcinoma |
2 (8) |
Cytological diagnosis |
|
Parathyroid lesion |
18 (72) |
Benign follicular cells |
2 (8) |
Adenomatous goiter |
2 (8) |
Atypical cells |
2 (8) |
Metastatic carcinoma |
1 (4) |
Histologic diagnosis |
|
Parathyroid adenoma |
18 (72) |
Parathyroid carcinoma |
2 (8) |
Nonea
|
5 (20) |
Table 2.Summary of cytological features
Cytological features |
No. (%) |
Architectural features |
|
Scattered naked nuclei |
25 (100) |
Loose clusters |
22 (88) |
Papillary pattern with fibrovascular core |
17 (68) |
Tight clusters |
14 (56) |
Follicular pattern |
11 (44) |
Nuclear features |
|
Anisokaryosis |
24 (96) |
Stippled chromatin |
21 (84) |
Eccentric nuclei |
2 (8) |
Prominent nucleoli |
1 (4) |
Intranuclear pseudoinclusion |
1 (4) |
Other features |
|
Well-defined cell border |
9 (36) |
Oxyphilic cytoplasm |
9 (36) |
Colloid-like material |
3 (12) |
Macrophages |
0 (0) |
Table 3.Clinical findings of the seven patients who are misdiagnosed
Feature |
No. (%) |
Serum parathyroid hormone |
|
Normal |
5 (71.4) |
Elevated |
1 (14.3) |
Unknown |
1 (14.3) |
Location |
|
Posterior to thyroid gland |
2 (28.6) |
Inferior to thyroid gland |
2 (28.6) |
Intrathyroidal |
1 (14.3) |
Paratracheal |
2 (28.6) |
Clinicoradiologic impression |
|
Incidentaloma |
3 (42.9) |
Primary hyperparathyroidism |
1 (14.3) |
Parathyroid lesion |
1 (14.3) |
Metastatic papillary thyroid carcinoma |
2 (28.6) |
Treatment |
|
Minimally invasive parathyroidectomy |
4 (57.1) |
Total thyroidectomy and central neck dissectiona
|
1 (14.3) |
Lobectomy |
1 (14.3) |
Neck dissection |
1 (14.3) |