Malignant solitary fibrous tumor of the thyroid: a case-report and review of the literature

Abstract

SUMMARYSolitary fibrous tumor (SFT) is an uncommon spindle-cell neoplasm that most often involves the pleura, rarely occurring in extra-thoracic locations. Twenty-six cases of SFT arising in the thyroid gland have been described. We report a case of a 60-year-old woman presenting an 8-month history of enlargement of the neck associated with dysphagia. The patient underwent a right hemithyroidectomy and SFT of the thyroid was diagnosed. Immunohistochemistry showed positivity for CD34 marker, and the high number of mitoses and the presence of cellular atypia suggested that the tumor was malignant. To our knowledge, this is the second case of malignant SFT of the thyroid gland ever reported. Due to the rarity of these tumors, the indication of adjuvant therapy and prognosis are uncertain. Long-term follow-up after surgical resection seems to be advisable. Arq Bras Endocrinol Metab. 2014;58(4):402-6 RESUMO O tumor fibroso solitário (SFT) é uma neoplasia rara de células fusiformes que mais frequentemente envolve a pleura, raramente ocorrendo em áreas extratorácicas. Já foram descritos 26 casos de SFT da tiroide. Relatamos o caso de uma paciente de 60 anos de idade com um histó-rico de 8 meses de aumento do pescoço associado à disfagia. A paciente foi submetida a uma hemitiroidectomia direita e foi diagnosticado um SFT de tiroide. A imuno-histoquímica mostrou resultados positivos para o marcador CD34, e o grande número de mitoses e a presença de atipia celular sugerem que o tumor era maligno. Em nosso conhecimento, este é o segundo caso de STF da tiroide maligno já relatado. Dada a rara ocorrência desses tumores, a indicação de tratamento adjuvante e o prognóstico são incertos. Recomenda-se o acompanhamento de longo prazo depois da ressecção cirúrgica. Arq Bras Endocrinol Metab. 2014;58(4):402-6

A case report of solitary fibrous tumor of the thyroid gland and literature review

“…An SFT of the thyroid gland can be difficult to distinguish from other tumors, such as anaplastic carcinomas, hemangiopericytomas, medullary carcinomas, sarcomas, leiomyomas, neurofibromas, schwannomas, and Riedel's thyroiditis. [7,10,14,15] A diagnosis of an SFT of the thyroid gland can only be made after the exclusion of other thyroid tumors that exhibit spindle-cell morphology. [16] SFTs of the thyroid gland have a distinct morphology that is often referred to as a "patternless" pattern, showing spindle cell growth interspersed with hypercellular and hypocellular patches.…”

“…[16] SFTs of the thyroid gland have a distinct morphology that is often referred to as a "patternless" pattern, showing spindle cell growth interspersed with hypercellular and hypocellular patches. [10] Present within areas of the tumor were filled thyroid gland follicles of different sizes. SFTs are histologically characterized by proliferative ovoid to spindle-shaped tumor cells surrounded by intermittent staghorn vessels and structured with a fibrocollagenous to myxoid matrix.…”

“…An SFT of the thyroid gland can be difficult to distinguish from other tumors, such as anaplastic carcinomas, hemangiopericytomas, medullary carcinomas, sarcomas, leiomyomas, neurofibromas, schwannomas, and Riedel’s thyroiditis. [7,10,14,15] A diagnosis of an SFT of the thyroid gland can only be made after the exclusion of other thyroid tumors that exhibit spindle-cell morphology. [16]…”

“…[9] In the other case, there were no intraoperative symptoms of malignancy, and the patient had preoperative hoarseness and no postoperative follow-up information. [10] We reviewed the medical records of 42 SFTs of the thyroid gland published between 1993 and 2022. Among them, follow-up information was missing for 13 patients.…”