Scalp Metastasis from Follicular Hürthle-Cell Carcinoma of the Thyroid Challenges and Follow-up

Abstract

Overall, skin metastases from internal malignancies are a rare event, ranging from 0.9% to 4.4% in large autopsy studies and reaching 9% in large series of patients. Skin metastases from thyroid carcinoma are even rarer and, among them, follicular carcinomas have seldom been reported in this context, far less so than papillary and medullary carcinomas. A 57-year-old Caucasian male presented with an angioma-like papule on the parietal area of the scalp with a 4-month history. The patient had endured 2 years previously total thyroidectomy, radiotherapy and several chemotherapeutical regimens for a metastatic Hürthle cell carcinoma of the thyroid gland. Excisional biopsy of the nodules established the diagnosis of metastatic (lung and liver) follicular cell carcinoma on plain histological and immunohistochemical grounds. Lymph nodes, lungs and bones are the most common sites of distant metastases of thyroid carcinomas. Although accounting for about 12% of all thyroid carcinomas, skin metastases from follicular carcinomas have however only rarely been reported. These tumours are usually well-differentiated carcinomas, bearing a fair long-term prognosis and characterized pathologically by the presence of follicular structures and colloid material in the midst of diverse amounts of anaplasia and architectural disorganization. In our case, it is noteworthy the angioma-like morphology of the metastatic nodule, classically associated with renal cell carcinoma scalp metastases, as well as its aggressive nature which led eventually to a fatal outcome. This case is ichnographically depicted and a review of the relevant literature is done.