Extrapleural solitary fibrous tumor of the thyroid gland: A case report and review of literature

BACKGROUND

Solitary fibrous tumor (SFT) is an uncommon mesenchymal neoplasm that arises from the pleura. A few SFTs have also been described in extrapleural sites. However, SFT of the thyroid gland is rare. Here, we report a case of extrapleural SFT on the thyroid gland, in addition to a literature review.

CASE SUMMARY

A 59-year-old man visited our hospital in July 2017 complaining of a large mass in his neck. His thyroid function test results, including antibody levels, were within the normal limits. Ultrasonography showed a 4.7 cm × 4.0 cm × 3.2 cm solitary mass of intermediate suspicion in the left thyroid lobe. A fine-needle aspiration biopsy was subsequently performed. The pathologist reported a benign follicular lesion. However, the size of this nodule increased to 5.5 cm × 5.0 cm × 3.4 cm by April 2018. After a multidisciplinary discussion, a left lobectomy was performed in May 2018. The specimen showed a well-demarcated, partly encapsulated, soft nodule of whitish and tan/brown color on the cut surface. Light microscopy revealed high cellularity with moderate cytologic atypia. The mitotic count was 5/10 high-power fields. There was no tumor necrosis or lymphovascular invasion. The tumor was CD34-positive and signal transducer and activator of transcription 6-positive. Neither thyroid transcription factor-1 nor cytokeratin expression was detected. The Ki-67 showed intermediate proliferative activity. The final diagnosis was extrapleural SFT of the thyroid gland with a clear resection margin. The patient was discharged without complication three days after the surgery.

CONCLUSION

In the literature, extrapleural SFT of the thyroid gland has been reported to behave indolently with the capacity for recurrence and rare metastasis, although surgical resection is the treatment of choice. Understanding this disease entity is important for accurate diagnosis and proper management.

A Novel Technique for Performing Transoral Endoscopic Thyroidectomy Vestibular Approach (TOETVA): A Single-port Platform

During transoral endoscopic thyroidectomy vestibular approach (TOETVA), the mental nerve can be injured by the lateral ports. Mental nerve injury is a worrisome complication, which can be minimized by using the single-port platform. A 56-year-old woman was diagnosed with a 5-mm sized papillary thyroid carcinoma on the isthmus. A horizontal 21-mm incision was made on the mucosa at the lower lip, followed by vertical dissection from the mentalis muscles down to the mandibular area. Subsequent hydrodissection widened the working space. For the single-port procedure, the KeyPort system was applied. After inserting the endoscopic instruments, the thyroid isthmus was resected as usual. The patient was discharged without any complications. To our knowledge, this is the first report of single-port TOETVA. Although the indications are limited, a single-port platform can be utilized for TOETVA. This will minimize the risk of mental nerve injury.

Transcriptome Analysis Reveals Significant Differences in Gene Expression of Malignant Pheochromocytoma or Paraganglioma

Prediction of malignant behavior of pheochromocytoma (PC) or paraganglioma (PG) is of limited value. The Cancer Genome Atlas (TCGA) and the French 'Cortico et Médullosurrénale: les Tumeurs Endocrines' (COMETE) network in Paris (France) facilitate accurate differentiation of malignant PC/PG based on genetic information. Therefore, the objective of this transcriptome analysis is to identify the prognostic genes underlying the differentiation of malignant PC/PG in the TCGA and COMETE databases. TCGA carries data pertaining to multigenomic analysis of 173 PC/PG surgical resection samples while the COMETE cohort contains data involving 188 PC/PG surgical resection samples. Clinical information and mRNA expression datasets were downloaded from TCGA and COMETE databases. Based on eligibility criteria, 58 of 173 PC/PG samples in TCGA and 171 of 188 PC/PG samples collected by the COMETE network were selected. Using Ingenuity Pathway Analysis, the mRNA expression of malignant and benign PC/PG was compared. The 58 samples in TCGA included 11 malignant and 47 benign cases. Among the 171 samples obtained from the COMETE cohort, 19 were malignant and 152 were benign. A comparative analysis of the mRNA expression data of the two databases revealed that 11 up/downregulated pathways involved in malignant PC/PG were related to cancer signaling, metabolic alteration, and prominent mitosis, whereas 6 upregulated genes and 1 downregulated gene were significantly enriched in the functional annotation pathways. The TCGA and COMETE databases showed differences in mRNA expression associated with malignant and benign PC/PG. Improved recognition of prognostic genes facilitates the diagnosis and treatment of PC/PG.