Primary neurilemoma of the thyroid gland: a case report

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.

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.

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.

A Cervical Schwannoma Masquerading as a Thyroid Nodule

BACKGROUND

We present a case of a cervical schwannoma, likely originating from the pharyngeal plexus of the vagal nerve. The lesion masqueraded as a thyroid nodule and magnetic resonance imaging (MRI) assisted in preoperative diagnosis. We review the radiographic characteristics of nerve sheath tumors on MRI as well as the diagnostic cytologic stains which can enhance the possibility of a correct preoperative diagnosis.

CASE

We describe a 60-year-old female with dysphagia and a neck mass consistent with a nodular goiter. The patient's history, diagnostic images, cytology, pathology, and surgical management are presented and analyzed. The preoperative diagnosis of a cervical schwannoma was suspected by the use of MRI which led to additional specialized cytologic stains.

CONCLUSION

Pharyngeal wall schwannomas are important to consider in the differential diagnosis of thyroid nodules when fine needle aspiration cytology indicates cells of neural origin. Imaging by MRI can assist in identifying lesions of neural origin masquerading as thyroid nodules.

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.

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.

Primary neurilemmoma of the thyroid gland in a 12-year-old girl

A case of a neurilemmoma of the thyroid gland in a 12-year-old girl is reported. The tumor was noted as a asymptomatic left lower neck swelling 9 months before admission. Ultrasound scan showed the solid lesion of predominantly hypoechoic structure measuring 17.2 x 12 x 26 mm within the left lobe. Pathologic examination of the excised lobe was consistent with neurilemmoma with both Antoni A and Antoni B histologic patterns. To date only 14 cases of this nonepithelial tumor of the thyroid gland have been described in the literature, and all occurred in adult patients. This is the first report of thyroid neurilemmoma in a child.

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.