Ultrastructure of a primary fibrosarcoma of the human thyroid gland

Primary thyroid fibrosarcoma in a 32-year-old female: case report and literature review

Thyroid fibrosarcomas represent a rare subset of tumors with exceedingly limited documented cases in the medical literature. This study delineates an unusual occurrence involving a 32-year-old female presenting with symptoms including neck pain, dysphagia, and dyspnea. Notably, the patient experienced symptom recurrence 3 months postthyroidectomy, accompanied by aggressive tumor growth. Despite the considerable size of the tumor and its infiltration into critical anatomical structures, a complex surgical intervention was executed with successful outcomes. The study underscores the imperative for further exploration into the efficacy of proposed therapeutic modalities tailored for managing this neoplasm. Moreover, it emphasizes the necessity for considering the histological classification of fibrosarcoma within the differential diagnoses spectrum for thyroid tumors.

Hemangiopericytoma of the Thyroid

A 52-year-old woman presented with a painless right thyroid mass of 4 months dura tion, with a recent increase in size in the last few weeks. The neoplasm was character ized by bland spindle cells with a low mitotic rate arranged around vascular elements of variable shape and caliber. Multiple immunohistochemical stains failed to show evi dence of epithelial, neuroendocrine, or specific mesenchymal differentiation. Electron microscopic studies revealed spindle cells with micropinocytotic vesicles, surrounded by variable but sometimes abundant basement lamina-like material. To the authors' knowledge, this is the first report of a typical hemangiopericytoma of the thyroid gland. This lesion must be distinguished from epithelial and neuroendocrine tumors with spindle cells and from other mesenchymal neoplasms that may occur in the thyroid. Int J Surg Pathol 2(4):311-318, 1995

Rare Undifferentiated Tumour of Thyroid: Primary Thyroid Fibrosarcoma

Primary thyroid fibrosarcoma cases are very rare. Although it is a known fact that soft tissue sarcomas show slow growth, there have been some cases in literature similar to our case in which there was a fast-growing tumour tissue causing breathing and swallowing difficulties due to painless pressure. For diagnosis, there is no specific clinical or radiological finding. We report a 67-year-old male with a mobile fast-growing mass covering almost all over the neck that appeared 2 months prior to the admission. Laboratory findings showed that the patient was euthyroid. Fine needle aspiration biopsy results are consistent with suspicion of a mesenchymal, histiocytic, epithelial or lymphoid tissue origined malignancy. Patient was taken into surgical operation. The thyroid tissue invaded the main vascular structure, trachea and esophagus. Due to this situation R1 resection was applied. Immunohistopathological examination showed a conventional type of fibrosarcoma. After the surgery, radiotherapy and chemotherapy had been planned and applied. Patients died before the radiotherapy sessions ended. It should be kept in mind that a rapid growth in thyroid tissue can be thyroid fibrosarcoma, there could be a rapid clinical course and poor prognosis after operation.

Update on anaplastic thyroid carcinoma: morphological, molecular, and genetic features of the most aggressive thyroid cancer

Anaplastic thyroid carcinoma (ATC) is the most aggressive form of thyroid cancer. It shows a wide spectrum of morphological presentations and the diagnosis could be challenging due to its high degree of dedifferentiation. Molecular and genetic features of ATC are widely heterogeneous as well and many efforts have been made to find a common profile in order to clarify its cancerogenetic process. A comprehensive review of the current literature is here performed, focusing on histopathological and genetic features.

Fine-needle aspiration biopsy of primary osteosarcoma of the thyroid: report of a case and review of the literature

Primary osteosarcoma of the thyroid is an extremely rare tumor, with only 27 well-documented cases reported in the literature, including only one in the cytology literature. We describe here an additional case with fine-needle aspiration biopsy findings. A 60-year-old woman presented with a 1-month history of progressive midline neck swelling. CT and ultrasound demonstrated a large thyroid mass with tracheal compression. Fine-needle aspiration biopsies were performed and showed pleomorphic spindle and epithelioid neoplastic cells, multinucleated giant cells, and scant metachromatic extracellular matrix material. Cell block sections contained minute tissue fragments with neoplastic spindle cells. Immunohistochemical stains showed the tumor cells to be positive for vimentin and negative for cytokeratins, TTF-1, calcitonin, synatophysin, chromogranin, and S-100 protein, suggesting a sarcoma; however, the differential diagnosis also included anaplastic thyroid carcinoma and medullary thyroid carcinoma. Tissue biopsy revealed a high-grade spindle cell neoplasm with osteoid production, consistent with osteosarcoma of the thyroid. The patient developed a large pulmonary embolus and superior vena cava syndrome and no further surgical intervention was performed. She died 5 weeks after the initial diagnosis. Upon retrospective review, the cytologic features resemble osteosarcoma in other areas. Although cytologic features on fine-needle aspiration biopsy may suggest a diagnosis of this rare entity, definitive diagnosis should be deferred to histologic examination.

Spindle epithelial tumor with thymus-like differentiation (SETTLE) of the thyroid with prominent mitotic activity and focal necrosis

Spindle epithelial tumor with thymus-like differentiation (SETTLE) is a rare, apparently low-grade spindle cell tumor of the thyroid gland occurring in young individuals and thought to be derived from thymic or branchial pouch remnants. Spindle epithelial tumor with thymus-like differentiation has little to no mitotic activity, and focal necrosis has been reported in one case. We present a case of SETTLE in a 29-year-old man that was initially evaluated by fine-needle aspirate biopsy and ultimately found to be consistent histologically with SETTLE. In this case, there were numerous mitotic figures among the spindle cells and focal necrosis. Spindle epithelial tumor with thymus-like differentiation has been considered to be a tumor of low malignant potential with metastases developing some years after diagnosis. This is the first case in which prominent mitotic activity and necrosis is reported perhaps representing an aggressive variant.

Primary smooth muscle tumors of the thyroid gland

BACKGROUND

Primary smooth muscle tumors of the thyroid gland are rare. To date, there are few cases reported of primary thyroid leiomyomas and leiomyosarcomas.

METHODS

One leiomyoma and four leiomyosarcomas arising within the thyroid gland were identified in the files of the Endocrine Tumor Registry of the Armed Forces Institute of Pathology. Histologic and immunohistochemical features were reviewed and follow-up obtained.

RESULTS

The patients included 2 females, ages 56 and 64 years, and 3 males, ages 45, 68, and 83 years. The patients presented with a mass in the thyroid gland that had increased in size over a number of months. All the tumors originated within a single lobe of the thyroid gland and measured from 1.1 to 9 cm in greatest dimension. Histologically, there was a fascicular pattern of growth comprised of spindle-shaped cells with blunt-ended nuclei. The leiomyoma was encapsulated, cytologically bland, and amitotic; the leiomyosarcomas were invasive with increased cellularity, pleomorphism, a high mitotic rate, necrosis, and hemorrhage. Immunohistochemical staining showed reactivity with vimentin, smooth muscle actin, muscle specific actin, and desmin. The patient with the leiomyoma was alive without evidence of disease 11 years after the initial presentation, with surgical resection as the only treatment. Three of the patients with leiomyosarcomas were dead within 2 years of diagnosis, in spite of aggressive therapeutic intervention. The remaining patient was still alive 10 months after initial presentation with multiple lung metastases.

CONCLUSIONS

Smooth muscle tumors of the thyroid gland are distinctive tumors. Leiomyosarcomas can be distinguished from anaplastic carcinoma, although patient outcome is uniformly unfavorable.

Peripheral Nerve Sheath Tumors of the Thyroid Gland: A Series of Four Cases and a Review of the Literature

Primary peripheral nerve sheath tumors (PNSTs) of the thyroid gland are exceptionally rare. Two schwannomas and two malignant PNSTs (MPNSTs), arising primarily within the thyroid gland, were identified in the files of the Endocrine Tumor Registry at the Armed Forces Institute of Pathology. The patients included two females, age 69 and 80 yr, and two males, age 18 and 33 yr. The patients presented with a mass in the thyroid gland confined to a single lobe of the thyroid without involvement of the cervical neck region. None of the patients had a history of neurofibromatosis. The benign tumors were encapsulated, one of them cystic, with the characteristic cellular and nuclear features of schwannomas. The MPNSTs were invasive tumors, effacing the thyroid parenchyma, with a fascicular pattern of growth composed of neural appearing cells with increased cellularity, increased mitotic activity, and with focal necrosis. Immunoreactivity for 5100 protein and vimentin was seen in all tumors. The patients with schwannomas, treated only by surgical resection, were alive without evidence of disease, over a period of 5-33 yr. Both patients with MPNSTs died of the disease 8 mo and 42 mo, respectively, with widely disseminated disease. Primary thyroid PNSTs are exceptionally rare tumors. MPNSTs, in this limited experience, have a fatal outcome irrespective of aggressive adjuvant therapy.

Primary leiomyosarcoma of the thyroid gland

A primary leiomyosarcoma of the thyroid gland in a 72 year old Japanese woman is described. This is the second case reported in the English literature. The patient presented with a 7 month history of a gradually expanding tumor in the right neck. The surgical specimen taken by thyroid lobectomy revealed a relatively well demarcated tumor, 2 x 2 x 3 cm in size, confined to the right lobe. Histologically, the tumor showed a classical leiomyosarcomatous appearance of interlacing fascicles of spindle-shaped cells with occasional blunt-ended nuclei and a high frequency of mitotic figures. Immunohistochemistry of the tumor cells clearly showed smooth muscle differentiation; the cells were positive for desmin, muscle-specific actin and vimentin and negative for cytokeratin, epithelial membrane antigen, carcinoembryonic antigen, thyroglobulin and calcitonin. The patient was free of disease for 3 years and 11 months without further treatment when evidence of multiple bone metastases appeared on bone scintigraphy. She died of pneumonia 4 years and 3 months after the lobectomy.

Tumors of the neck showing thymic or related branchial pouch differentiation: a unifying concept

A number of rare tumors occurring in the soft tissues of the neck and the thyroid gland, reported in the literature under a variety of designations, show complete to partial histologic resemblance to the fetal, mature, or involuted thymus and mediastinal thymomas. This family of tumors spans a range of histologic appearances and behaviors from completely benign lesions to metastasizing malignant tumors. After reviewing the previously reported and new cases, we have been able to delineate four reasonably well-defined clinicopathologic entities within this spectrum. On the benign end is "ectopic hamartomatous thymoma," which occurs in the soft tissues of the lower neck. It is characterized by spindle epithelial cells, solid or cystic epithelial islands, and adipose cells which intermingle haphazardly to impart a hamartomatous quality. In the middle of the spectrum are the ectopic cervical thymomas which are usually benign, but can sometimes be locally invasive and can exceptionally metastasize. They are histologically identical to mediastinal thymomas, and residual ectopic thymus is not uncommonly identifiable in the periphery of the tumor. On the malignant end are tumors we have designated as "spindle epithelial tumor with thymus-like differentiation" (SETTLE) and "carcinoma showing thymus-like differentiation" (CASTLE). Tumors of the SETTLE type occur in the thyroid gland of young patients, and are highly cellular tumors comprised of compact bundles of long spindle epithelial cells which merge with tubulopapillary structures and/or mucinous glands. Tumors of the CASTLE type are histologically similar to thymic carcinoma of the lymphoepithelioma or squamous cell variety. We postulate that this family of tumors arises either from ectopic thymus or remnants of branchial pouches which retain the potential to differentiate along the thymic line.

Leiomyosarcoma of the thyroid gland. A case report with a comparative study of five cases of anaplastic carcinoma

We report on a case of leiomyosarcoma of the thyroid with ultrastructural features and expression of intermediate filament proteins different from that of anaplastic carcinomas. Histologic examination of multiple sections showed that they were leiomyosarcomatous, and neither epithelial features nor giant cell configurations were found. Electron microscopic examination showed microfilament bundles with dense patches and discontinuous basal lamina. Desmin, vimentin, and actin were positive for tumor cells, and cytokeratin, thyroglobulin, and calcitonin were negative. In contrast, the anaplastic carcinoma cases did not contain microfilament bundles with dense patches in their tumor cells. There were no desmin-positive or cytokeratin-negative tumor cells. We concluded that this case was a primary leiomyosarcoma, presumably derived from the smooth muscle cell of the vascular wall.

Cellular junctions in a spectrum of human malignant tumors

Cellular junctions in tumors are often considered a hallmark of epithelial differentiation. However, junctions are also seen in tumors having a different differentiation. This observation prompted us to study cellular junctions in malignant nonepithelial tumors. We found a variety of cellular junctions in such tumors, although the majority were poorly formed. This observation is of importance for diagnostic purposes. We have also tried to clarify the nomenclature of cellular junctions as applied in tumor diagnosis by proposing a systematic categorization of terms in everyday use by pathologists and by referring more extensively to the term paired subplasmalemmal densities (PSD) for non-well-formed junctions.

Anaplastic thyroid carcinoma: an ultrastructural study of 10 cases

Anaplastic carcinoma of the thyroid is an aggressive, rapidly fatal neoplasm that is generally believed to arise from the epithelium of the thyroid follicle. When differentiated carcinoma is not present, the diagnosis can be difficult and confusion with a sarcoma is frequently a problem. Ten anaplastic thyroid carcinomas have been examined by light and electron microscopy and compared with two biologically aggressive, solid follicular carcinomas. Ultrastructural study revealed evidence of epithelial differentiation in all the anaplastic carcinomas, confirming their origin from thyroid follicular cells. The study illustrates the value of electron microscopy in establishing the diagnosis of anaplastic carcinoma and in differentiating it from sarcoma.

Differential diagnosis of spindle cell tumours by electron microscopy--personal experience and a review

Electron microscopy has its value and its limitations in refining the histogenetic diagnosis of certain spindle cell tumours. The ultrastructural diagnostic features of neural tumours, muscle tumours, fibrous histiocytomas, fibrosarcomas, monophasic synovial sarcoma and spindle-cell squamous carcinoma are reviewed and illustrated.