Downloaded from http://pmj.bmj.com/ on May 24, 2015 - Published by group.bmj.com
Images in medicine
Micro-medullary thyroid carcinoma: a diagnosis not to be missed INTRODUCTION Incidental diagnosis of a thyroid nodule is very common on adult neck ultrasound (US) examination. In such cases, extensive knowledge of thyroid nodule semiology on high frequency Doppler ultrasound and of thyroid imaging reporting and data system (TIRADS) nodule classification is mandatory.1 Thyroid nodules presenting with US findings suspicious for malignancy (ie, strong hypoechogenicity, irregular margins, microcalcifications, greater height than width, and a high stiffness ratio on elastography) should undergo fine needle aspiration cytology (FNAC) and further cytological analysis according to the Bethesda 2010 classification, irrespective of thyroid nodule size. Doppler US assessment may also help identify supplementary suspicious features including anarchic central vasculature and a high resistance index (RI >0.75). Medullary thyroid carcinomas (MTC) represent 5% of thyroid malignancies and have a significantly poorer prognosis than well-differentiated papillary and follicular cancers. A high level (>100 pg/mL) of serum thyrocalcitonin (TCT) usually indicates macro-MTC. MTC also may show some particular US Doppler features.
CASE DESCRIPTION A 11-year-old girl was referred to our institution for thyroid gland investigation. US examination showed a 5 mm hypoechoic ill-defined nodule presenting with echogenic foci (TIRADS5) at the mid part of the left thyroid lobe (figure 1). Serum calcitonin level was 17.7 pg/mL. The micronodule was suspicious for malignancy, suggesting a medullar thyroid microcarcinoma owing to: (a) suspicious US features, (b) nodule location, and (c) a mildly elevated serum TCT level. Thyroidectomy was performed and histopathological examination confirmed the diagnosis.
DISCUSSION As tumour volume and spread determines MTC prognosis, the radiologist should be familiar with specific MTC imaging findings, leading to prompt and early diagnosis in order to improve both the surgical management and long-term prognosis of this severe tumour. MTC usually arises in the upper or mid part of the central thyroid lobe where C ( parafollicular) cells are found. The tumour marker is serum TCT and seems highly specific. A high level (>100 pg/mL) of serum TCT usually indicates macro-MTC, while patients with very small tumours may show intermediate to low serum TCT levels (10–50 pg/mL). However, heavy smoking and proton-pump inhibitor (PPI) medication may induce false positive results, thus decreasing the specificity. In such cases, the diagnosis is based on: (a) a continuous increase over time in TCT serum level despite cessation of tobacco use and PPI medication, and (b) the presence of a suspicious solitary micronodule in the central portion of the upper/mid thyroid lobe. Moreover, frankly hyperechoic punctuations may correspond to amyloid deposits or calcifications, and should alert the radiologist to promptly perform a FNAC. As MTC may be linked to multiple endocrine neoplasia (RET mutation), enlarged parathyroid glands should also be sought at the posterior aspect of the thyroid lobes, medially to the cervical carotid sheaths. 236
Figure 1 The patient presented with histopathologically proven micro-MTC and a mild increase in serum thyrocalcitonin (TCT) level (17.7 pg/mL). Axial (A) and longitudinal (B) ultrasound scans showing a 5 mm hypoechoic ill-defined micronodule with typical echogenic foci (TIRADS5) at the mid part of the left thyroid lobe which was investigated with fine needle aspiration cytology and TCT wash-out fluid analysis. (C) Histopathological examination (×16) shows tumour cells. Immunohistochemical staining is positive for thyrocalcitonin. MTC, medullary thyroid carcinoma; TIRADS, thyroid imaging reporting and data system.
Congo red stain should be employed during cytological analysis in order to identify amyloid substance and thyrocalcitonin immunostaining (figure 1).2 3 Moreover, a high calcitonin level found in a real-time US-guided FNAC wash-out fluid sample will confirm the final diagnosis. This will help to improve the prognosis of this serious thyroid tumour.4
Lacout A, et al. Postgrad Med J April 2015 Vol 91 No 1074
Downloaded from http://pmj.bmj.com/ on May 24, 2015 - Published by group.bmj.com
Images in medicine Alexis Lacout,1 Sylvie Isaac,2 Pierre Yves Marcy3
To cite Lacout A, Isaac S, Marcy PY. Postgrad Med J 2015;91:236–237.
1
Received 13 December 2014 Revised 9 March 2015 Accepted 18 March 2015
Centre d’Imagerie Médicale, Aurillac, France 2 Service d’Anatomie Pathologique, Centre Hospitalier Lyon Sud, Hospices Civils de Lyon, Pierre Bénite, France 3 Radiodiagnostic Department, Polyclinique les fleurs, Ollioules, France Correspondence to Dr Alexis Lacout, Centre d’Imagerie Médicale, 47, Boulevard du Pont Rouge, Aurillac 15000, France; [email protected] Competing interests None.
Postgrad Med J 2015;91:236–237. doi:10.1136/postgradmedj-2014-133203
REFERENCES 1
Patient consent Obtained. Ethics approval Obtained.
2
Provenance and peer review Not commissioned; externally peer reviewed. ▸ Additional material is published online only. To view please visit the journal online (http://dx.doi.org/10.1136/postgradmedj-2014-133203).
3
4
Lacout A, et al. Postgrad Med J April 2015 Vol 91 No 1074
Russ G, Royer B, Bigorgne C, et al. Prospective evaluation of thyroid imaging reporting and data system on 4550 nodules with and without elastography. Eur J Endocrinol 2013;168:649–55. Das A, Gupta SK, Banerjee AK, et al. Atypical cytologic features of medullary carcinoma of the thyroid. A review of 12 cases. Acta Cytol 1992;36: 137–41. Bhanot P, Yang J, Schnadig VJ, et al. Role of FNA cytology and immunochemistry in the diagnosis and management of medullary thyroid carcinoma: report of six cases and review of the literature. Diagn Cytopathol 2007;35: 285–92. Diazzi C, Madeo B, Taliani E, et al. The diagnostic value of calcitonin measurement in wash-out fluid from fine-needle aspiration of thyroid nodules in the diagnosis of medullary thyroid cancer. Endocr Pract 2013;19:769–79.
237
Downloaded from http://pmj.bmj.com/ on May 24, 2015 - Published by group.bmj.com
Micro-medullary thyroid carcinoma: a diagnosis not to be missed Alexis Lacout, Sylvie Isaac and Pierre Yves Marcy Postgrad Med J 2015 91: 236-237
doi: 10.1136/postgradmedj-2014-133203 Updated information and services can be found at: http://pmj.bmj.com/content/91/1074/236
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Articles on similar topics can be found in the following collections Clinical diagnostic tests (356) Radiology (368) Thyroid disease (38) Endocrine cancer (15) Surgical oncology (58) Drugs: CNS (not psychiatric) (85) Genetics (117)
Notes
To request permissions go to: http://group.bmj.com/group/rights-licensing/permissions To order reprints go to: http://journals.bmj.com/cgi/reprintform To subscribe to BMJ go to: http://group.bmj.com/subscribe/
Images in medicine
Micro-medullary thyroid carcinoma: a diagnosis not to be missed INTRODUCTION Incidental diagnosis of a thyroid nodule is very common on adult neck ultrasound (US) examination. In such cases, extensive knowledge of thyroid nodule semiology on high frequency Doppler ultrasound and of thyroid imaging reporting and data system (TIRADS) nodule classification is mandatory.1 Thyroid nodules presenting with US findings suspicious for malignancy (ie, strong hypoechogenicity, irregular margins, microcalcifications, greater height than width, and a high stiffness ratio on elastography) should undergo fine needle aspiration cytology (FNAC) and further cytological analysis according to the Bethesda 2010 classification, irrespective of thyroid nodule size. Doppler US assessment may also help identify supplementary suspicious features including anarchic central vasculature and a high resistance index (RI >0.75). Medullary thyroid carcinomas (MTC) represent 5% of thyroid malignancies and have a significantly poorer prognosis than well-differentiated papillary and follicular cancers. A high level (>100 pg/mL) of serum thyrocalcitonin (TCT) usually indicates macro-MTC. MTC also may show some particular US Doppler features.
CASE DESCRIPTION A 11-year-old girl was referred to our institution for thyroid gland investigation. US examination showed a 5 mm hypoechoic ill-defined nodule presenting with echogenic foci (TIRADS5) at the mid part of the left thyroid lobe (figure 1). Serum calcitonin level was 17.7 pg/mL. The micronodule was suspicious for malignancy, suggesting a medullar thyroid microcarcinoma owing to: (a) suspicious US features, (b) nodule location, and (c) a mildly elevated serum TCT level. Thyroidectomy was performed and histopathological examination confirmed the diagnosis.
DISCUSSION As tumour volume and spread determines MTC prognosis, the radiologist should be familiar with specific MTC imaging findings, leading to prompt and early diagnosis in order to improve both the surgical management and long-term prognosis of this severe tumour. MTC usually arises in the upper or mid part of the central thyroid lobe where C ( parafollicular) cells are found. The tumour marker is serum TCT and seems highly specific. A high level (>100 pg/mL) of serum TCT usually indicates macro-MTC, while patients with very small tumours may show intermediate to low serum TCT levels (10–50 pg/mL). However, heavy smoking and proton-pump inhibitor (PPI) medication may induce false positive results, thus decreasing the specificity. In such cases, the diagnosis is based on: (a) a continuous increase over time in TCT serum level despite cessation of tobacco use and PPI medication, and (b) the presence of a suspicious solitary micronodule in the central portion of the upper/mid thyroid lobe. Moreover, frankly hyperechoic punctuations may correspond to amyloid deposits or calcifications, and should alert the radiologist to promptly perform a FNAC. As MTC may be linked to multiple endocrine neoplasia (RET mutation), enlarged parathyroid glands should also be sought at the posterior aspect of the thyroid lobes, medially to the cervical carotid sheaths. 236
Figure 1 The patient presented with histopathologically proven micro-MTC and a mild increase in serum thyrocalcitonin (TCT) level (17.7 pg/mL). Axial (A) and longitudinal (B) ultrasound scans showing a 5 mm hypoechoic ill-defined micronodule with typical echogenic foci (TIRADS5) at the mid part of the left thyroid lobe which was investigated with fine needle aspiration cytology and TCT wash-out fluid analysis. (C) Histopathological examination (×16) shows tumour cells. Immunohistochemical staining is positive for thyrocalcitonin. MTC, medullary thyroid carcinoma; TIRADS, thyroid imaging reporting and data system.
Congo red stain should be employed during cytological analysis in order to identify amyloid substance and thyrocalcitonin immunostaining (figure 1).2 3 Moreover, a high calcitonin level found in a real-time US-guided FNAC wash-out fluid sample will confirm the final diagnosis. This will help to improve the prognosis of this serious thyroid tumour.4
Lacout A, et al. Postgrad Med J April 2015 Vol 91 No 1074
Downloaded from http://pmj.bmj.com/ on May 24, 2015 - Published by group.bmj.com
Images in medicine Alexis Lacout,1 Sylvie Isaac,2 Pierre Yves Marcy3
To cite Lacout A, Isaac S, Marcy PY. Postgrad Med J 2015;91:236–237.
1
Received 13 December 2014 Revised 9 March 2015 Accepted 18 March 2015
Centre d’Imagerie Médicale, Aurillac, France 2 Service d’Anatomie Pathologique, Centre Hospitalier Lyon Sud, Hospices Civils de Lyon, Pierre Bénite, France 3 Radiodiagnostic Department, Polyclinique les fleurs, Ollioules, France Correspondence to Dr Alexis Lacout, Centre d’Imagerie Médicale, 47, Boulevard du Pont Rouge, Aurillac 15000, France; [email protected] Competing interests None.
Postgrad Med J 2015;91:236–237. doi:10.1136/postgradmedj-2014-133203
REFERENCES 1
Patient consent Obtained. Ethics approval Obtained.
2
Provenance and peer review Not commissioned; externally peer reviewed. ▸ Additional material is published online only. To view please visit the journal online (http://dx.doi.org/10.1136/postgradmedj-2014-133203).
3
4
Lacout A, et al. Postgrad Med J April 2015 Vol 91 No 1074
Russ G, Royer B, Bigorgne C, et al. Prospective evaluation of thyroid imaging reporting and data system on 4550 nodules with and without elastography. Eur J Endocrinol 2013;168:649–55. Das A, Gupta SK, Banerjee AK, et al. Atypical cytologic features of medullary carcinoma of the thyroid. A review of 12 cases. Acta Cytol 1992;36: 137–41. Bhanot P, Yang J, Schnadig VJ, et al. Role of FNA cytology and immunochemistry in the diagnosis and management of medullary thyroid carcinoma: report of six cases and review of the literature. Diagn Cytopathol 2007;35: 285–92. Diazzi C, Madeo B, Taliani E, et al. The diagnostic value of calcitonin measurement in wash-out fluid from fine-needle aspiration of thyroid nodules in the diagnosis of medullary thyroid cancer. Endocr Pract 2013;19:769–79.
237
Downloaded from http://pmj.bmj.com/ on May 24, 2015 - Published by group.bmj.com
Micro-medullary thyroid carcinoma: a diagnosis not to be missed Alexis Lacout, Sylvie Isaac and Pierre Yves Marcy Postgrad Med J 2015 91: 236-237
doi: 10.1136/postgradmedj-2014-133203 Updated information and services can be found at: http://pmj.bmj.com/content/91/1074/236
These include:
References Email alerting service
Topic Collections
This article cites 4 articles, 1 of which you can access for free at: http://pmj.bmj.com/content/91/1074/236#BIBL Receive free email alerts when new articles cite this article. Sign up in the box at the top right corner of the online article.
Articles on similar topics can be found in the following collections Clinical diagnostic tests (356) Radiology (368) Thyroid disease (38) Endocrine cancer (15) Surgical oncology (58) Drugs: CNS (not psychiatric) (85) Genetics (117)
Notes
To request permissions go to: http://group.bmj.com/group/rights-licensing/permissions To order reprints go to: http://journals.bmj.com/cgi/reprintform To subscribe to BMJ go to: http://group.bmj.com/subscribe/
