Parathyroid Lesions Mimic Thyroid Nodules Especially When They are Located in the Thyroid Gland

Parathyroid Lesions Mimic Thyroid Nodules Especially When They are Located in the Thyroid Gland

Parathyroid Lesions Mimic Thyroid Nodules Especially When They are Located in the Thyroid Gland

Parathyroid Lesions Mimic Thyroid Nodules Especially When They are Located in the Thyroid Gland.


Parathyroid adenoma in the thyroid diagnosed by needle washout. left thyroid nodule was positive for TG negative for PTH, and the right parathyroid adenoma was positive for PTH negative for TG.


Patient with clinical hyperparathyroidism and a nodule in the thyroid that on needle washout was a parathyroid adenoma.

Comments by Dr.Guttler

This is backward thinking in this article by pathologists. You start with a patient with high serum calcium/PTH and you don’t find the adenoma by ultrasound, or parathyroid scan. Opps there happens to be a thyroid nodule found instead. This nodule is suspect to be a intrathyroidal parathyroid adenoma until proven otherwise. Well don’t you think the next step is a biopsy but with simple needle washout for thyroglobulin and parathyroid hormone? Why all this talk about being able to tell a parathyroid lesion from a thyroid lesion by cytology is not necessary as the diagnosis is already made by finding low TG and high PTH in the needle washout.Why spend money on molecular markers ThyroSeq v.2. because the cytology is indeterminate when you have the diagnosis without depending on cytology or markers.

Think like a clinician and don’t relay on pathologists to answer the question if it is parathyroid or thyroid by getting a simple needle washout for TG/PTH.

Richard Guttler MD,FACE,ECNU

Clinical thyroidologist

Further comments included in the two articles below.



Distinguishing parathyroid and thyroid lesions on ultrasound-guided fine-needle aspiration: A correlation of clinical data, ancillary studies, and molecular analysis

Cho M et al. Distinguishing parathyroid and thyroid lesions on ultrasound-guided fine-needle aspiration: a correlation of clinical data, ancillary studies, and molecular analysis. Cancer. June 16, 2017 [Epub ahead of print].


Differentiating parathyroid and thyroid lesions can be challenging because of considerable morphologic overlap and anatomic proximity. Therefore, the authors sought to identify characteristic morphologic patterns and useful adjunct tests to distinguish these 2 entities.

  1. There are no diagnostic parathyroid cytology. Only suggestive findings. 


A search was conducted in the study institution database for clinically indeterminate thyroid nodules from 2000 through 2016 with an emphasis on confirmed parathyroid nodules. Pathology reports, slides, ancillary studies, molecular analysis, and clinical and radiologic data were retrieved.


2. All cytology patterns are unspecific.

A total of 143 cases of clinically indeterminate thyroid nodules were identified; 34 of these were confirmed parathyroid nodules. Three cytologic patterns were identified: 1) oncocytic cell pattern (9 cases; 26%); 2) follicular lesion of undetermined significance-like/papillary-like pattern (14 cases; 41%); and 3) nonspecific endocrine cell clusters (11 cases; 32%). Bare oval nuclei (100%), nuclear overlap (88%), crowded sheets (88%), and intracytoplasmic vacuoles (62%) were observed.

3. Pathologists love to do more tests including, immunostaining for parathyroid hormone (PTH), ThyroSeq v.2.A simple needle washout from the biopsy is the answer not letting the case get out of hand by having pathologists get involved.

Ten cases (29%) demonstrated positive immunostaining for parathyroid hormone (PTH), 7 cases (21%) demonstrated a positive PTH assay, and 9 cases (26%) had PTH detected by ThyroSeq v.2. The remaining 8 cases were morphologically either indeterminate or suggestive of parathyroid origin. The cytologic diagnosis was confirmed clinically (20 cases) or surgically (14 cases).


Based on cytology alone, 8 cases initially were diagnosed as thyroid tissue and amended to parathyroid lesion after ancillary studies were performed, including 5 cases based on ThyroSeq v.2 results alone.

4. This is highly unlikely to happen as there is no diagnostic cytology pattern that separate thyroid from parathyroid lesions.


5. The conclusions are correct. Even after their attempt to use cytology to diagnose parathyroid lesions they could only SUGGEST not diagnose based on cytology alone.

Lesions with follicular lesion of undetermined significance-like or oncocytic features are prone to misdiagnosis. The current study identified distinct cytologic patterns in parathyroid lesions suggestive of parathyroid origin, which, together with PTH immunostains or assay, molecular studies, or sestamibi scans, aid in distinguishing parathyroid from thyroid lesions. Cancer Cytopathol 2017;125:674-82. © 2017 American Cancer Society.

6. Clinicians need to use their heads and save the expense of immunostains, and costly ThyroSeq v.2 to diagnose an intrathyroidal parathyroid adenoma by thinking about the possibility of a parathyroid adenoma when first noting a thyroid nodule in a patient with hyperthyroidism by clinical findings. Simple needle washout from the nodules will make the diagnosis 100% of the time when cytology is only suggestive.

Parathyroid lesions can be diagnosed by biopsy, but will need additional testing

CTFP Volume 11 Issue 1


The parathyroid glands control blood calcium levels. There are 4 parathyroid glands and are found right next to the thyroid gland on both sides. The normal parathyroid gland is usually not visible on ultrasound imaging. An enlarged parathyroid gland can indicate the disorder hyperparathyroidism, where calcium levels are very high. Surgery is often required for treatment of hyperparathyroidism. Parathyroid glands can sometimes look like thyroid nodules on ultrasound and other imaging, especially when they are found in unusual locations such as inside the thyroid gland. In these cases, biopsy is often considered to evaluate whether it is thyroid vs parathyroid.

However, biopsy of a parathyroid gland usually is indeterminate, as parathyroid identification requires special stains. The goal of this study was to determine if other, less involved methods such as simple pattern recognition on cytology, could be used to accurately distinguish parathyroid from thyroid lesions with a thyroid biopsy specimen.

7. Dr. Goldfarb, you aren’t serious about special stains. These are not necessary if the patient is evaluated by an endocrinologist.They would know that the nodule in the thyroid may be a parathyroid adenoma and with a simple needle washout made the diagnosis while your pathologist buddies were still ordering expensive immunostaining and Molecular markers.


Cho M et al. Distinguishing parathyroid and thyroid lesions on ultrasound-guided fine-needle aspiration: a correlation of clinical data, ancillary studies, and molecular analysis. Cancer. June 16, 2017 [Epub ahead of print].


A total of 143 indeterminate thyroid biopsy specimens were reviewed by experienced pathologists. Almost 25% were confirmed to actually be parathyroid tissue and not an indeterminate thyroid lesion. In these 34 parathyroid lesions, 3 different simple cytologic patterns were identified and there were many consistent cytologic features as well.


8. Dr.Goldfarb please it is only a challenge if you wait for the pathologist to call the biopsy indeterminate and get his immunostains and has you rebiopsy to get molecular markers. 

The identification of parathyroid glands that are within the thyroid is often a challenge. This study identifies characteristics of what a parathyroid lesion looks like under the microscope and should help cytopathologists to consider that diagnosis for thyroid lesions they are determining to be indeterminate.

7. Dr. Melanie Goldfarb is not an endocrinologist but a surgeon, and was in my opinion not the correct person to write this review for clinical thyroidology for the public. She misses the key points in how to diagnose parathyroid lesions from thyroid lesions.

— Melanie Goldfarb, MD, MS, FACS, FACE

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  • Sharon Pendleton November 30, 2019 8:13 pm

    This is scary! My PTH and calcium levels are high in blood work. They diagnosed me with primary hyper parathyroidism. Now they found a suspicious tirad 5 nodule, 1.4cm on my left thyroid and having a biopsy next week. Your thoughts? I’ll be 65 in May, female. Thank you.

    • Dr Guttler December 1, 2019 3:22 pm

      There may be treatment without surgery for both.
      RFA can treat parathyroid and very small thyroid cancers.
      Let me know the result of the biopsy.

      if it is negative we can ablate the parathyroid with RF and no surgery.

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