Malignant schwannoma of the thyroid gland

Primary schwannoma of the thyroid gland: analysis of case characteristics and review of the literature

BACKGROUND

To improve the characteristics of primary thyroid schwannomas (PTS) and to provide reference basis for clinical diagnosis and treatment.

METHODS

PubMed was searched for case reports of PTS up to December 2022 using the search terms "Thyroid nerve sheath tumor" or "Thyroid schwannoma" or "Thyroid Neurilemmoma", respectively. 34 cases were screened.

RESULTS

PTS can occur at any age, nodules averaged 3.9 cm. The most common symptoms were voice change and dysphagia. Fine needle aspiration cytology showing spindle-shaped cells should be considered for schwannoma. Most cases underwent thyroid lobectomy or nodule removal with a good prognosis. Tissue types with both Antoni A and Antoni B features are common. Positive immunohistochemical staining for S-100 protein, CD34 and waveform proteins helped confirm the diagnosis.

CONCLUSIONS

Positive immunohistochemistry for S-100 and wave proteins helps confirm the diagnosis. Preoperative diagnosis is challenging, but pathology and immunohistochemical staining are the gold standard for diagnosis. The first choice of treatment is surgical resection of the nodules, the prognosis is good.

Neck Surgery for Non-Well Differentiated Thyroid Malignancies: Variations in Strategy According to Histopathology

Lymph node metastases in non-well differentiated thyroid cancer (non-WDTC) are common, both in the central compartment (levels VI and VII) and in the lateral neck (Levels II to V). Nodal metastases negatively affect prognosis and should be treated to maximize locoregional control while minimizing morbidity. In non-WDTC, the rate of nodal involvement is variable and depends on the histology of the tumor. For medullary thyroid carcinomas, poorly differentiated thyroid carcinomas, and anaplastic thyroid carcinomas, the high frequency of lymph node metastases makes central compartment dissection generally necessary. In mucoepidermoid carcinomas, malignant peripheral nerve sheath tumors, sarcomas, and malignant thyroid teratomas or thyroblastomas, central compartment dissection is less often necessary, as clinical lymphnode involvement is less common. We aim to summarize the medical literature and the opinions of several experts from different parts of the world on the current philosophy for managing the neck in less common types of thyroid cancer.

Thyroid-Bed Schwannoma Mimicking a Thyroid Neoplasm: A Challenging Diagnosis: Report of a Case and Literature Review

Background: Schwannomas, also called neurinomas, are rare benign tumors of the neural cells that can develop from the sheaths of nervous structures of several districts, although the most frequent sites are the cranial nerves (25%–45%). Rarely, cases show neck schwannomas in the thyroid parenchyma, while the cases of thyroid-bed schwannomas mimicking a thyroid-gland lesions are anecdotal. Methods: We report the case of a 70-year-old man with a preoperative-imaging diagnosis of a thyroid neoplasm, confirmed as Thyr 4 by fine-needle cytology. Results: During surgery, an extra-thyroidal lesion was discovered, determined to be a neck schwannoma through definitive pathology. A literature review of cases of thyroid-bed-lesion schwannomas misinterpreted as thyroid neoplasms was carried out. Conclusions: In the case of suspicious extra-thyroidal lesions, we advocate for a close routine cooperation between the cytologist, the radiologist, and the surgeon in the attempt to reach an accurate preoperative diagnosis.

Comprehensive guidance on the diagnosis and management of primary mesenchymal tumours of the thyroid gland

Most primary thyroid tumours are of epithelial origin. Primary thyroid mesenchymal tumours are rare but are being increasingly detected. A vast majority of thyroid mesenchymal tumours occur between the fourth and seventh decades of life, presenting as progressively enlarging thyroid nodules that often yield non-diagnostic results or spindle cells on fine needle aspiration biopsy. Surgery is the preferred mode of treatment, with adjuvant chemoradiotherapy used for malignant thyroid mesenchymal tumours. Benign thyroid mesenchymal tumours have excellent prognosis, whereas the outcome of malignant thyroid mesenchymal tumours is variable. Each thyroid mesenchymal tumour is characterised by its unique histopathology and immunohistochemistry. Because of the rarity and aggressive nature of malignant thyroid mesenchymal tumours, a multidisciplinary team-based approach should ideally be used in the management of these tumours. Comprehensive guidelines on the management of thyroid mesenchymal tumours are currently lacking. In this Review, we provide a detailed description of thyroid mesenchymal tumours, their clinical characteristics and tumour behaviour, and provide recommendations for the optimal management of these tumours.

Malignant peripheral nerve sheath tumour of thyroid: a diagnostic dilemma

Malignant peripheral nerve sheath tumours of thyroid are rare entities that can present a diagnostic dilemma. We present the case of a patient who presented with neck mass with a history of multiple neck surgeries and airway compression. The patient's previous histopathology was mistaken for Riedel's thyroiditis in an outside hospital, which delayed appropriate treatment leading to suffering on part of the patient and frustration on part of the physician. We emphasise that rare malignancies should be considered in rapidly growing neck masses that are causing airway compression, and histopathology of such tumours should be reported by expert pathologists.

Schwannoma of the thyroid bed: A case report and review of the literature

RATIONALE

Schwannomas involving the thyroid gland are very rare and only a few cases have been reported in the literature. However, previous reports did not distinguish between thyroid bed schwannomas and intrathyroidal schwannomas. Here, we report a thyroid bed schwannoma mimicking a malignant thyroid nodule and review the literature on thyroid bed schwannomas.

PATIENT CONCERNS

A 33-year-old woman presented at our hospital with mild neck swelling.

DIAGNOSIS

Thyroid ultrasound revealed a well-defined, oval-shaped, markedly hypoechoic solid nodule with echogenic foci suggesting macro- and microcalcifications in the left thyroid gland. The lesion was considered a "highly suspicious" intrathyroidal nodule, based on the guidelines for the assessment of thyroid nodules. Fine needle aspiration was performed twice, but the cytological results were nondiagnostic.

INTERVENTIONS

Left thyroidectomy was performed, and schwannoma of the thyroid bed was confirmed on histopathologic analysis.

OUTCOMES

The patient was in a stable condition after surgery, and the thyroid function test results were within the normal range.

LESSONS

Diagnosis of a schwannoma of the thyroid bed is challenging because its incidence is extremely low, and it is often misdiagnosed as an intrathyroidal nodule on ultrasonography. Therefore, it is advisable to adopt a diagnostic strategy to perform additional core needle biopsy in cases of thyroid nodules with nondiagnostic fine needle aspiration results and to consider the location of the lesion more carefully to determine the suitable therapy.

Report of a case of malignant peripheral nerve sheath tumor of the neck with an early local recurrence

Malignant peripheral nerve sheath tumor (MPNST), which originates in Schwann cells, is uncommon in the head and neck. These highly aggressive sarcomas are characterized by local recurrence and distant metastasis. Many are associated with neurofibromatosis type 1; the survival rate in such cases is poorer than the rate associated with tumors that arise de novo. Hypercellularity and pleomorphism are cardinal microscopic features. Immunohistochemical staining is widely used to determine S-100 positivity and a Ki-67 score, either of which may establish the prognosis. We present a case of MPNST of the neck that arose in a 17-year-old girl, who was also found to have a parapharyngeal neurofibroma. The cervical mass was excised (intraoperative complications precluded removal of the parapharyngeal mass) and radiotherapy was administered, but the patient experienced a recurrence within 2 months. Another surgery was performed, and this time both tumors were removed. At 1 year of follow-up, the patient was without disease, but in postoperative year 2, she died from complications of a cervical recurrence and mediastinal metastasis.

Primary peripheral nerve sheath tumors of the thyroid gland

BACKGROUND

Primary peripheral nerve sheath tumors (PNSTs) of the thyroid gland are exceptionally rare tumors that usually present as asymptomatic neck nodules in adults. This article presents a literature review of these tumors.

SUMMARY

PNSTs of the thyroid can be classified into benign and malignant. Only three cases of malignant PNSTs have been reported. Benign PNSTs of the thyroid include neurofibromas and schwannomas. Only two cases of isolated neurofibroma of the thyroid have been reported. Schwannomas are typically benign, slow-growing tumors that originate from neuronal schwann cells, with a clinical picture depending on the anatomic size and site. Pathologically, schwannomas are classified into Antoni A and Antoni B. Only 17 cases of schwannomas of the thyroid exist in literature to date.

CONCLUSIONS

Schwannomas of the thyroid gland are extremely rare and usually asymptomatic. Complete surgical resection is mandatory for care.

Malignant peripheral nerve sheath tumor of the thyroid: a clinicopathological and ultrastructural study of one case

Thyroid malignant peripheral nerve sheath tumors (TMPNST) are very uncommon neoplasms that can be confused with anaplastic carcinoma, Riedel's thyroiditis, or other soft tissue tumors that may occur in the thyroid region. An example of TMPNST is presented in this report. The tumor occurred in a 56-yr-old woman. Fine needle aspiration did not provide adequate material. After thyroidectomy, the lesion posed important problems in differential diagnosis. Immunohistochemical, molecular, and electron microscopic features were taken into consideration to arrive at the correct diagnosis. Tumor cells were focally positive for keratins, a feature that has not been described in peripheral nerve sheath tumors of the thyroid, but that has been occasionally seen in tumors from other locations. After thyroidectomy, the patient received radiotherapy. She is well without evidence of recurrence 10 mo after surgery.