Primary schwannoma of the thyroid gland involving the isthmus: report of a case

Cytopathology of mesenchymal tumors of the thyroid gland: analysis of 12 cases from multinational institutions with review of the literature

INTRODUCTION

Mesenchymal tumors of the thyroid gland are extremely rare. We report the cytomorphologic characteristics of 12 mesenchymal tumors occurring in the thyroid gland and highlight the diagnostic difficulties encountered in their cytologic evaluation.

MATERIALS AND METHODS

The cytopathology and surgical pathology archives from 5 large institutions were searched for thyroid mesenchymal tumors that had an FNA available for review. Clinicopathologic and cytomorphologic characteristics for each case were evaluated.

RESULTS

Twelve cases of mesenchymal tumors occurring in the thyroid were identified in our search. Patient age ranged from 28 to 84 years (median, 60 years). The cases occurred in 7 women and 5 men. The tumor size ranged from 1.4 to 14 cm (median, 3.3 cm). The tumors were as follows: hemangioma (n = 4; 33.3%), angiosarcoma (n = 2; 16.7%), schwannoma (n = 2; 16.7%), solitary fibrous tumor (n = 2, 16.7%), metastatic synovial sarcoma (n = 1, 8.3%) and metastatic pleomorphic rhabdomyosarcoma (n = 1, 8.3%). The cytomorphologic features of the tumors were similar to those of their counterparts occurring in different sites. An accurate diagnosis was achieved in six primary thyroid mesenchymal cases (60%). Five patients (41.7%) underwent total thyroidectomy, and 3 patients received partial thyroidectomy (25%). Three patients (25%) did not receive a thyroidectomy and subsequent surgical information was not available in 1 case (8.3%).

CONCLUSIONS

Mesenchymal tumors of the thyroid are extremely uncommon. Cytologic diagnosis of these tumors is often challenging due to the morphologic overlap with diverse epithelial and non-epithelial thyroid lesions. Ancillary studies such as immunohistochemistry and molecular studies are essential for accurate diagnosis.

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.

Multimodal ultrasound imaging of primary thyroid schwannoma: A case report

RATIONALE

Primary schwannoma of the thyroid gland is very rare, and its preoperative diagnosis is difficult.

PATIENT CONCERNS

We report the case of a thyroid nodule in an 18-year-old woman, who presented with a mass in her left neck with stiffness and normal thyroid function. However, the patient complained of numbness in her left upper extremity, and ultrasound (US) features were suspicious of malignancy.

DIAGNOSES

Multimodal US imaging was performed using B-mode, color doppler, ultrasonic elastography (UE), and contrast-enhanced ultrasound (CEUS). CEUS revealed heterogeneous enhancement and "target sign" within the tumor. The nodule was suspicious for malignancy and classified as TI-RADS 4b, while the elasticity values measured by UE indicated a benign lesion. Fine needle aspiration (FNA) was subsequently performed in the markedly contrast-enhanced area for biopsy. Cytological results revealed a benign schwannoma.

INTERVENTION

The patient underwent left lobe resection. Postoperative pathology confirmed it to be a primary benign schwannoma of the thyroid.

OUTCOMES

After thyroidectomy, the patient was followed-up with US. At present, all laboratory tests and thyroid imaging are normal, and the numbness of the left upper limb has disappeared.

LESSONS

The combination of different US modalities is useful for the diagnosis of thyroid lesions. FNA performed under CEUS guidance improves the accuracy of biopsy sampling.

Unusual Thyroid Nodule: A Case of Symptomatic Thyroid Schwannoma

Primary thyroid schwannoma is a sporadic non-epithelial tumor of the thyroid gland. Most previous cases reported in the literature presented it as an asymptomatic neck mass. In this report, we describe a rare case of thyroid schwannoma in a 33-year-old female, presented as a left-side neck swelling, accompanied by a change in voice and difficulty swallowing. An ultrasound of the mass showed a large heterogeneous, predominantly cystic, nodule; in contrast to the usual predominantly solid nodule described in the literature. After several pre-operative diagnostic tests, including fine needle aspiration (FNA), the diagnosis remained unclear. In the end, the patient underwent a successful surgical excision of the mass, and the diagnosis of schwannoma was confirmed based on the histopathologic examination which revealed both type A and B Antoni cells as well as positive staining for S-100 protein.

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.

Primary peripheral nerve sheath tumors of the thyroid gland: A case report and literature review

Primary peripheral nerve sheath tumors (PNSTs) of the thyroid gland are rare, with fewer than 30 cases reported in the medical literature to date. Primary PNSTs of the thyroid gland are classified into malignant and benign PNSTs. The benign PNSTs may be further subclassified into neurofibromas and Schwannomas. This is the case report of a 51-year-old male patient presenting with multiple primary PNSTs involving the left lobe of the thyroid gland. The patient underwent total excision of the thyroid gland and the pathological results indicated a Schwannoma with Antoni type A and B cells. The literature was reviewed briefly and, to the best of our knowledge, this is the first case report of multiple primary PNSTs of the thyroid gland.

Schwannoma mimicking a neoplastic thyroid nodule

Schwannoma is a rare benign tumor of nerve fibers that originates from neuronal sheath cells; it is frequently located extramedullary and about 25-45 % of this type of neoplastic lesion is localized in the head and in the neck. Primary schwannoma of the thyroid gland is very uncommon. We report the case of a 50-year-old female patient affected by schwannoma of the thyroid gland underwent total thyroidectomy for nodule of the left lobe suspicious for neoplasm, without complications.