Thyroid & parathyroid
Benign thyroid neoplasms
Solitary thyroid nodule
Author: Sheren Younes, M.D., Ph.D.
Last author update: 1 July 2014
Last staff update: 15 April 2024 (update in progress)
Copyright: 2014-2024, PathologyOutlines.com, Inc.
PubMed Search: solitary thyroid nodule
Table of Contents
Definition / general | Epidemiology | Etiology | Diagnosis | Radiology description | Radiology images | Case reports | Microscopic (histologic) description | Microscopic (histologic) images | Cytology description | Positive stains | Videos | Additional referencesCite this page: Younes S. Solitary thyroid nodule. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/thyroidsolitary.html. Accessed April 20th, 2024.
Definition / general
- A discrete lesion within the thyroid gland that is palpably or ultrasonographically distinct from surrounding thyroid parenchyma
- Up to 5% are malignant (Oncologist 2008;13:105)
- Single and cold (on nuclear scan) nodules are higher risk for malignancy, but 80 - 90% are benign; other risk factors are radiation to head and neck, rapidly enlarging nodule, ipsilateral adenopathy, male patient, age < 20 years or > 70 years
- Cysts may represent cystic degeneration of follicular adenoma or portions of multinodular goiters
Epidemiology
- Usually > 1 cm
- Variable prevalence worldwide, depending on iodine deficiency
Etiology
- Colloid nodule (hyperplastic nodule)
- Thyroid cysts
- Focal / asymmetrical thyroiditis, acute suppurative, granulomatous or Hashimoto's thyroiditis
- Thyroid adenoma, ectopic thymic tissue, other benign tumors
- Primary thyroid malignancies and metastasis:
- Papillary carcinoma
- Follicular carcinoma
- Medullary carcinoma
- Anaplastic carcinoma
- Primary lymphoma of thyroid
- Metastatic carcinoma (especially breast and renal cell carcinoma)
Diagnosis
- Use these factors:
- Asymptomatic
- Pain and rapid enlargement
- Age and sex of patient
- History of prior radiation exposure
- Compression symptoms on surrounding structures
- Lymph node involvement or metastasis
- Hypo-, eu-, or hyperthyroidism
- Thyroid function tests
- Ultrasound, radiologic investigations
- Biopsy
- Evaluate with ultrasound guided fine needle aspiration (see Cytology: FNA) to rule out malignancy
- Nonpalpable nodules greater than 1.0 to 1.5 cm represent an absolute indication to perform an ultrasound guided fine needle biopsy (ANZ J Surg 2006;76:381, Hormones (Athens) 2007;6:101)
Radiology description
- Thyroid ultrasound
- Most effective
- Determine size and shape of nodule, presence of associated nodules or lesions
- Determine if cystic or solid
- Benign lesions are pure cystic, spongiform or septate, multiple
- Suspicious features are solid, calcification, hypoechoic lesion and increased vascularity
- Radionucleotide scanning
- Hot, cold and warm nodules
- CT and MRI help evaluate extent of lesion if malignant
Radiology images
Images hosted on other servers:
Multiple hypoechoic lesions
Case reports
- 6 year old girl with ectopic intrathyroidal thymus as cause of a solitary thyroid nodule (An Pediatr (Barc) 2013;78:64)
- 19 year old woman with paraganglioma of thyroid gland (BMJ Case Rep 2013;2013)
- 38 year old man with primary cavernous hemangioma of thyroid (J Clin Diagn Res 2014;8:151)
- 56 year old woman with solitary extramedullary plasmacytoma (Diagn Cytopathol 2014;42:964)
- 64 year old woman with squamous cell carcinoma of esophagus presenting as solitary nodule thyroid (Indian J Surg Oncol 2012;3:41)
- Metastases to thyroid gland from renal cancer (Tumori 2013;99:e107)
Microscopic (histologic) description
- Description of histology for primary lesion:
- Hashimoto's thyroiditis: small follicles with Hürthle cell change and marked lymphoplasmacytic infiltrate
- Follicular adenoma / carcinoma: follicular proliferation, variable colloid component, trabecular, solid, micro and macrofollicular architecture; vascular and capsular invasion are diagnostic of malignancy
- Papillary carcinoma: true papillae, cells have characteristic nuclear features, psammoma bodies
Microscopic (histologic) images
Images hosted on other servers:
Hemangioma
Metastatic squamous cell carcinoma
Cytology description
- FNAC is gold standard in diagnosis
- Cytologic features to evaluate include cellularity, colloid, acinar and papillary formation, nuclear features, Hürthle cells, atypia, inflammatory component
- Bethesda system for reporting thyroid lesions:
Positive stains
- CK19 staining favors papillary carcinoma and Galectin3 staining favors follicular carcinoma (Histopathology 2002;41:236)
- Galectin3 has high sensitivity for differentiation of benign and malignant thyroid lesions (Mod Pathol 2003;16:1117)
Videos
Thyroid cytology: colloid nodule
Solitary thyroid nodule
Thyroid: compare and contrast
Additional references
