This report describes a patient who presented with a large thyroid nodule and compressive symptoms. Immunohistochemical staining showed diffuse marked reactivity for vimentin and focal reactivity for CD68 and Ki-67 that is compatible with primary undifferentiated pleomorphic sarcoma of the thyroid. This report emphasizes and discusses extremely rare thyroid cancer type.

Primary undifferentiated pleomorphic sarcoma is extremely rare in the thyroid, and can be easily misdiagnosed as anaplastic thyroid cancer.

We present a case of a 71-year-old woman who presented with a rapidly growing painless mass in the neck.

Computed tomography showed a large hypointense mass with hyperdense areas involving whole of the right lobe of thyroid gland and fine-needle aspiration cytology found a few atypical cells. Surgical exploration was performed subsequently and frozen section showed malignant tumor. Therefore, a total thyroidectomy, central, and bilateral lateral neck dissection were performed and adjuvant radiotherapy of 60 Gy was administered. The patient was alive and had no recurrence at 6-month follow-up.

Although primary undifferentiated pleomorphic sarcoma in the thyroid is extremely rare, patients who presented with a rapidly growing painless mass in the neck should be considered and it is essential to excise the tumor completely as soon as possible.

Primary malignant fibrous histiocytoma of the thyroid is an uncommon malignancy of the thyroid. Because it is rare, fewer than 20 cases have been reported in the literature, and the sonographic features of only 2 cases have been reported between the 1980s and 2014. Here we report 2 cases of primary malignant fibrous histiocytoma of the thyroid with an emphasis on the sonographic findings, and we review the published literature.

Primary Malignant Fibrous Histiocytoma (MFH-T) and Leiomyosarcoma (LMS-T) of the thyroid gland are extremely rare tumors. Very few cases have been reported in the literature. Both entities occur more commonly in women than men. The closest clinical and histological differential diagnosis is anaplastic carcinoma of thyroid. We present three cases of rare primary sarcomas of thyroid gland. Case-1 was a 63-year-old woman and Case-2 was a 52-year-old woman. Both of them presented with a rapidly increasing thyroid mass clinically mimicking anaplastic carcinoma (AC-T). Both the patients developed pulmonary metastasis and succumbed to the illness soon after the diagnosis of MFH-T was made. Case 3 was 65-year-old woman with neck swelling since six months diagnosed as LMS-T. The present communication adds three new cases to the literature on sarcomas of thyroid gland with an emphasis on differential diagnosis of spindle cell lesions of thyroid. MFH-T and LMS-T needs to be differentiated from AC-T, metastatic sarcomas, spindle cell variant of medullary carcinoma, synovial sarcoma, fibrosarcoma; final diagnosis rests on histopathology and immunohistochemistry.

This study was conducted to investigate the natural history of undifferentiated thyroid carcinoma (UTC) in the iodine-deficient province of Salta, Argentina, in relation to salt iodization and health care standards. Five hundred ninety-three thyroid cancers diagnosed from 1958 to2012 were reviewed based mainly on the WHO classification and grouped into three periods, one before and two after iodine prophylaxis. The incidence of UTC was analyzed in relation to changing concentrations of potassium iodide (KI) in salt during the prophylaxis period (from 40 to 33.3 mg KI/kg salt), establishment of primary health care centers throughout the region, and use of fine needle aspiration (FNA) cytology. Twenty-nine UTCs were found in the whole series. The frequency of UTC decreased from 15.2 % (9/59 cases) in the first period to 2.6 % (10/381 cases) well after salt iodination (x (2) Fisher's test, p < 0.0002), and the incidence from 1.4/10(6)/year to 0.1/10(6)/year (Student's t test, p < 0.06), respectively. The decline of UTC after iodine prophylaxis occurred even after decreasing concentrations of KI in salt and timely coincided with the establishment of primary health care centers throughout the region and routine use of FNA. The lower rate of UTC after iodine prophylaxis in the province of Salta is mostly related to earlier detection of more differentiated thyroid tumors rather than higher salt iodization.

Malignant tumors of the thyroid that consist of merged histological types are a rare clinical entity, with an obscure pathogenesis and no consensus of opinion on nomenclature. Eight patients with merged histological types of thyroid malignant tumor at a single medical center were enrolled between January 1977 and December 2009. These patients were surgically treated and were followed postoperatively from 1 month to 34 years. Preoperative patient characteristics, B-type ultrasonography, computed tomography scan, thyroid function tests, postoperative pathology, immunohistochemistry, and prognosis data were collected. Merged histological types of thyroid malignant tumor accounted for 0.12% of all thyroid malignant tumors treated during this period. Preoperative imageology and laboratory data have no specific value toward diagnosis of merged histological types of thyroid malignant tumor. Merged histological types of thyroid carcinoma that had undergone radical resection in combination with hormonal therapy and I(131) radiotherapy achieved a satisfactory outcome, while other merged thyroid malignant tumors were usually associated with a poor prognosis. Prognosis depended on the highest grade among an individual group of malignant tumors.

Malignant mesenchymoma of the thyroid is extremely rare. We report such a tumor involving the bilateral lobes of the thyroid which showed simultaneous chondrosarcomatous, osteosarcomatous, fibrosarcomatous and rhabdomyosarcomatous differentiation. The patient was a 52-year-old woman admitted with a history of facial swelling, neck thickness and swallowing discomfort of one month's duration. Sonographic examination indicated a thyroid mass involving the bilateral lobes. Macroscopically, the tumors of both lobes were well demarcated, solid, greyish-white, and multinodular on the cut surface. Some nodules were translucent in appearance and hard in texture. Microscopically, the tumor was composed of small primitive mesenchymal cells with osteoid formation resembling the small cell variant of osteosarcoma interspersed with multiple cartilaginous nodules that indicated chondrosarcomatous differentiation. Some tumor cells showed prominent rhabdomyoblastic differentiation with eosinophilic cytoplasm and eccentric nuclei. Fibrosarcomatous areas were also observed. Immunohistochemically, the small primitive mesenchymal cells were positive for vimentin and CD99 and negative for CD56, Syn, CgA, CK, TG, TTF-1, calcitonin, and S-100. The tumor cells in the rhabdomyosarcomatous area were MyoD1 and muscle-specific actin positive. Molecular analysis for BRAFand RAS gene alterations showed no point mutation. The tumor recurred four months after surgery and tumor thrombi were suspected in the bilateral internal carotid arteries on ultrasonography. Primary malignant mesenchymoma of the thyroid is a high-grade malignant tumor with a poor prognosis. Its differerential diagnosis includes anaplastic carcinoma and other rare sarcomas with chondroid, osteoid, and other mesenchymal metaplasia.

To study the clinical features, diagnosis, and treatment of primary malignant fibrous histiocytoma of the thyroid (MFH-T). Treatment and outcome were analyzed retrospectively in a consecutive series of 12 patients with primary MFH-T treated at the Cancer Hospital of the Chinese Academy of Medical Sciences from 1987 to 2007.

All 12 patients underwent surgery; surgery alone was used in four patients. Five patients were given post-operative radiotherapy, and one patient was given pre-operative radiotherapy. Two patients were given post-operative chemotherapy. Five patients had locoregional recurrence, and five had distant metastases in follow-up. Median survival was 9 months. One patient is alive, and has no evidence of disease. Six patients died six months after treatment, and the other four patients died in 10, 14, 18, and 24 months after treatment, respectively. Nine patients died of the disease, and one patient died of cerebral hemorrhage after treatment.

Primary MFH-T is very rare and has a poor prognosis. Although surgical resection of MFH-T is the treatment of choice in MFH-T, the results are unsatisfactory.