Medullary thyroid carcinoma (MTC) could coexist with ectopic bone formation (EBF) inside the thyroid gland, according to a study recently published in the journal European Review for Medical and Pharmacological Sciences.

“Based on our view, we recommend that all patients with histopathological findings of EBF or EMH in thyroid biopsy or thyroidectomy specimens should be evaluated with further analysis such as bone marrow biopsy and genetic tests for possible underlying hematological problems,” the authors wrote.

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This observational, retrospective study consisted of a case series that included 16 patients who had previously undergone bilateral total thyroidectomy and had a postoperative histopathologic confirmation of an EBF in the resected tissue. The researchers selected these cases after reviewing 3100 thyroidectomy specimens.

Of all individuals, 1 also had a diagnosis of MTC. This patient further underwent a central neck dissection. Among the remaining cases, 8 had EBF as the only histologic diagnosis, 3 also had papillary thyroid carcinoma, 1 papillary thyroid microcarcinoma, 1 follicular adenoma, and 1 lymphocytic thyroiditis.

The patient with coexisting MTC had the EBF localized in the right lobule, as did 5 other participants. Only 1 had bilateral EBF, and the remaining 9 had this finding only on the left lobule. Moreover, the majority had euthyroid function tests (n=12), did not have a simultaneous hematologic disorder (n=11), and presented with neck swelling (n=12). All participants had a radiologic diagnosis of multinodular goiter with bilateral nodule location.

The patient with MTC shared all of the above characteristics. She was 50 years of age, and the largest nodule size was 13 mm. Likewise, most individuals (n=13) were females, and the age varied from 43 to 66 years of age, with a median of 56 years.

Understanding the pattern of thyroid diseases that lead to thyroidectomy could aid in the prompt diagnosis of EBF and extramedullary hematopoiesis.

“Cases of multinodular goiter, thyroid hyperplasia, follicular adenoma, papillary thyroid carcinoma, and anaplastic thyroid carcinoma have been reported with histopathologic findings of osseous metaplasia (OM), bone marrow metaplasia, EBF, ossification, and EMH,” the authors noted.


Sogutcu N, Akbulut S, Sari A, et al. Ectopic bone formation in thyroid gland: report of sixteen cases and comprehensive literature review. Eur Rev Med Pharmacol Sci. Published online February 2023. doi:10.26355/eurrev_202302_31193