A team from Kuma Hospital in Kobe, Japan reported the case of a patient with a melanin‑producing medullary thyroid carcinoma (MTC) that evolved into melanoma.

The case, published in Molecular and Clinical Oncology, was the second of its kind to be reported. “In comparison with the case reported previously, the morphology of the present case was similar, but the outcome was poorer,” the study authors reported.

The patient, an 86-year-old male, presented with a right anterior neck mass that had been increasing in size for 3 years. Subsequent examination showed the presence of a well-encapsulated, soft nodule in the right lobe of the thyroid.

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The nodule was mainly composed of large pleomorphic cells and small spindle cells, which displayed a solid or alveolar growth pattern. The cells stained positive for melan‑A and S‑100, which was consistent with melanoma.

Additional presurgical analysis showed increased levels of serum calcitonin and carcinoembryonic antigen (CEA). Thyroid function tests were normal.

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“As the pathological diagnosis was melanoma, thyroid metastasis of melanoma was considered and an extensive examination at the dermatology department of another hospital was performed after the operation, but no primary site of the melanoma was detected,” the team explained.

The patient underwent total thyroidectomy without neck nodal dissection, and serum calcitonin and CEA levels returned to normal. Unfortunately, he died 3 years later due to a brain tumor, which was assumed to be a metastasis of the melanoma.

“Although no definitive diagnosis was obtained regarding whether the brain tumor was metastasis of the melanoma or a primary tumor such as glioma because no autopsy was performed, the clinical course led to the assumption that the cause of death was brain metastasis of the melanoma,” the authors stated.

In contrast, the patient from the first case showed no signs of recurrence or distant metastasis over an 11-year follow-up period.


Yoshikawa KI, Tanimura T, Hoshi M, et al. Melanin‑producing medullary thyroid carcinoma with transformation to melanoma: a case report. Mol Clin Oncol. 2022;16(2):34. doi:10.3892/mco.2021.2467