thyroid cancer accounts for 12% of all malignancies , representing the most common endocrine malignancy .
papillary carcinoma ( ptc ) is the most frequent among thyroid malignancies , whereas medullary thyroid carcinoma ( mtc ) accounts for 510% of cases .
mtc , on the other hand , originates from parafollicular cells of the ultimobranchial body , derived from the fourth pharyngeal pouch .
hereditary mtc can manifest either alone as familial mtc or as part of the multiple endocrine neoplasia type 2 syndromes ( men 2 ) .
men 2 involves medullary carcinoma and pheochromocytoma with either primary hyperparathyroidism ( men 2a ) or marfanoid habitus and mucosal neurofibromatosis ( men 2b ) .
concurrence of medullary and papillary thyroid carcinomas is an unusual finding . in this report , a case of multifocal thyroid cancer involving two foci of medullary and two foci of papillary microcarcinomas is presented .
a 39 year - old female presented for otorhinolaryngologic evaluation at the outpatient clinic of a tertiary referral center ( department of otorhinolaryngology , university hospital of heraklion , greece ) .
the examination had been performed as part of a routine assessment for reported difficulty in swallowing and neck discomfort complaints by the patient .
it had revealed slightly enlarged thyroid gland lobes , with presence of two nodules in the right lobe of the gland ( maximum diameter 0.3  cm and 0.8  cm , respectively ) and two nodules in the left lobe ( maximum diameter 0.4  cm and 0.6  cm , respectively ) .
ultrasound elastography had been used to complete the imaging study and revealed suspicious findings , with an elastography score of 4 in one , and 5 in all other nodules .
patient denied any past exposure to radiation as well as any family history of endocrine disorders .
clinical examination of the head and neck was unremarkable , and no masses were noted on palpation of the neck .
serum levels of calcium , thyroid stimulating hormone ( tsh ) , free thyroxine and thyroglobulin as well as parathyroid hormone were within normal range .
calcitonin levels , on the other hand , were increased ( 86  pg / ml ; normal values : < 12  pg / ml in women ) .
abdominal ultrasound did not show any adrenal pathology and urinary catecholamines and metanephrine levels were within normal limits .
ultrasound guided fine - needle aspiration ( fna ) cytology of the thyroid was performed twice , but was non - diagnostic .
this decision was based on increased levels of calcitonin in addition to findings on elastography that were suggestive of thyroid malignancy .
a transverse cervical incision was performed , subplatysmal flaps were raised and strap muscles were separated in the midline .
both lobes were completely removed after recognition and meticulous dissection of the recurrent laryngeal nerves .
postoperative course was uneventful and the patient was discharged from the hospital two days after surgery .
permanent histology of the specimen described the presence of two microscopic foci of medullary carcinoma as well as two papillary microcarcinomas .
more specifically , a papillary microcarcinoma ( diameter : 7  mm ) ( fig . 1a ) and a microscopic medullary carcinoma ( diameter : 1.3  mm ) ( fig .
1b ) were found in the right lobe , while hyperplastic c cells were detected next to the tumors . in the left lobe , a 4  mm papillary carcinoma
1c ) , as well as a microscopic medullary carcinoma with a diameter of 3.5  mm ( fig .
eleven lymph nodes had been removed , and all were found free of metastasis on histopathological examination .
due to multifocality of the papillary carcinoma , the patient underwent treatment with 100  mci of radioactive iodine ( i ) six weeks after surgery .
ten months later , the patient is under tsh suppression treatment with levothyroxine and retains low levels of thyroglobulin and calcitonin .
thyroid cancer is the most common endocrine malignancy , accounting for more than 90% of malignancies of the endocrine glands .
well - differentiated thyroid cancer , including papillary and follicular carcinomas , remains the most common thyroid malignancy , whereas medullary and anaplastic carcinomas represent 510% and 1.6% of cases , respectively .
the most common mutations described in well - differentiated thyroid carcinomas involve the braf gene , and are observed in 3669% of cases .
multifocality of both medullary and papillary components is a rare entity , and only two cases have been previously described in the literature .
the concurrence of ptc and mtc is an interesting phenomenon as these tumors have different embryological origin .
mtc originates from c cells of the ultimobranchial body , derived from the fourth pharyngeal pouch , whereas ptc originates from follicular epithelial cells , derived from median endodermal analogs .
several theories for this coexistence have been proposed . according to the  stem cell theory ,  uncommitted stem cells differentiate into both follicular and c - cell lineages .
the  divergent differentiation theory  states that c cells and thyroid follicles are derived from remnants of the ultimobranchial body and solid cell nests .
the  field effect theory  suggests that simultaneous transformation of both follicular and c cells is a result of common neoplastic stimuli . finally ,
 suggests that two independent tumors are located in the same lesion by simple coincidence .
cytological examination of material obtained by fna represents the best single diagnostic test for differentiating malignant from benign thyroid lesions .
elastography is a newly developed imaging technique that uses ultrasound to estimate tissue stiffness by measuring the degree of distortion under the application of an external force .
it is based upon the principle that softer components of tissues deform easier than harder components under compression , thus allowing an objective determination of tissue consistency .
elasticity of thyroid nodules is evaluated according to the rago classification system using a scale of 15 .
score 1 indicates high elasticity in the whole nodule ; score 2 indicates elasticity in a large part of the nodule ; in score 3 elasticity is detected only at the peripheral part of the nodule ; no elasticity in the nodule is detected in score 4 ; score 5 indicates no elasticity in the nodule as well as the posterior shadowing .
scores 13 are generally associated with benign lesions , while scores 45 are suggestive of malignancy .
ultrasound elastography demonstrates high sensitivity ( 97% ) and specificity ( 100% ) in the diagnosis of thyroid malignancy , with the predictive value of the examination being independent from the nodule size .
thus , elastography can be a reliable , noninvasive tool in the differential diagnosis of thyroid nodules .
in the case presented here , the decision to perform an fna and furthermore a thyroidectomy was largely based on the suspicious findings of elastography .
total or near total thyroidectomy is the preferred procedure for both ptc and mtc , since thyroid lobectomy is associated with a higher risk of recurrence .
therapeutic central neck dissection should be performed in cases of pathologic lymph node involvement noted on preoperative clinical and imaging assessment . on the other hand ,
thus , a prophylactic central neck dissection should be considered in patients with multifocal ptc , as in the case of our patient .
development of multiple , small foci of different histological types of thyroid carcinoma is a rare event .
elastography can be a useful and noninvasive tool in the differential diagnosis of small thyroid nodules .
written informed consent was obtained from the patient for publication of this case report and accompanying images .
a copy of the written consent is available for review by the editor - in - chief of this journal on request .
 introductiona few cases of concomitant medullary and papillary carcinoma in the same thyroid nodule have been described in the literature . however , the presence of multiple foci of both types of malignancy in the same gland is very rare.presentation of casea 39 year - old female with multiple thyroid nodules , elevated serum calcitonin levels and elastographic findings suggestive of thyroid malignancy , underwent total thyroidectomy and central neck dissection . 
 histology revealed the presence of one focus of medullary and one focus of papillary carcinoma on each thyroid lobe . 
 subsequently , the patient underwent treatment with radioactive iodine.discussionthis is the third case of synchronous multifocal medullary and papillary thyroid carcinoma reported in the literature . 
 several theories for the simultaneous development of these malignant entities have been proposed.conclusionultrasound elastography can be a useful , noninvasive tool in the assessment of thyroid nodules . 
Introduction
Presentation of case
Discussion
Conclusion
Conflict of interest
Funding
Ethical approval
Author contributions