SOX11 expression in a case of papillary thyroid carcinoma with fibromatosis/fasciitis-like stroma containing BRAF c.1799_1801delTGA and CTNNB1 c.133T>C mutations

Papillary thyroid carcinoma with nodular fasciitis-like stroma - an unusual variant with distinctive histopathology: A case report

BACKGROUND

Papillary thyroid carcinoma (PTC) is regarded as a fairly common endocrine malignancy, which can be divided into different multiple variants due to wide morphologic differences. The majority of PTC variants have been reported, but PTC with nodular fasciitis-like stroma (NFS) is a rare pathological variant and has been infrequently reported in the relevant literature. This condition involves abundant reactive stromal components rich in spindle cells, which may account for 60%-80% of the tumor along with a typical papillary carcinoma.

CASE SUMMARY

A 44-year-old man presented with a 4-mo history of a palpable mass over the anterior aspect of the left neck, the tumor demonstrated gradual enlargement but was painless during the 4 mo prior to discovery. Thyroid function test results were normal. Physical examination showed an enormous and firm nodular mass in the left lobe of the thyroid gland extending to the level of the hyoid bone. Ultrasonography of the neck revealed a well-defined heterogeneous lesion measuring around 5.0 cm × 4.0 cm with a hypoechoic complex nodule, decreased vascularity and speckles of microcalcification. The patient underwent left thyroidectomy with central compartment lymph node dissection. Final histopathological examination confirmed the diagnosis of PTC with extensive fibromatosis-like stroma combined with typical PTC. The patient was asymptomatic at the 3-mo follow-up.

CONCLUSION

PTC-NFS is a rare pathological variant and its diagnosis and prognosis may be similar to typical papillary carcinoma.

Papillary thyroid carcinoma with desmoid-type fibromatosis: the clinicopathological features with characteristic imaging and molecular correlation requiring comprehensive treatment

The pathogenesis and treatment of papillary thyroid cancer with desmoid-type fibromatosis (PTC-DTF), a rare subtype of papillary thyroid carcinoma characterized by a mixed epithelial-mesenchymal structure, are still ill-defined. Previous reports on PTC-DTF have had limited follow-up and recurrence has been rarely reported. To better understand this condition, we conducted a thorough analysis of five cases of PTC-DTF from our institute, including clinical and pathological examinations, imaging, immunohistochemistry, and molecular analysis. We also reviewed relevant literature. The mean age of the patients was 51.8 years, with three women and two men included in the group. Ultrasound often showed a hypoechogenic and well-defined nodule in the thyroid gland, except for one individual who had distant lung metastases detected by PET-CT. The nodules ranged in width from 0.5 to 5.0 cm and were excised in each case. Following surgery, ¹³¹I therapy was used in two cases. The overall number of PTC-DTF cases has risen from the previously reported 55 to 60, with females being the most commonly affected and ranging in age from 19 to 82. Most masses underwent a thyroidectomy, and approximately half of the patients had lymph node metastases. Histologically, PTC-DTFs were composed of a predominant stromal component (65% - 90%) and an intervening epithelial component. These spindle cells were arranged in parallel with abundant cytoplasm and vacuole-like nucleus but there wasn't evident atypia. The carcinoma cells were positively stained for CK and TTF-1 by immunohistochemistry, whereas mesenchymal cells were positive for SMA and displayed nuclear immunoreactivity for β-catenin. BRAF, NRAS, and CTNNB1 mutations were identified in the epithelial and mesenchymal components through molecular testing, respectively. Perhaps because the mesenchyme harbors aberrant nuclear β-catenin expression, PTC-DTF is more aggressive and prone to invasion and distant recurrence, as shown by our case 2, which is the first case to be reported thus far. PTC-DTF is typically treated with surgery, but clinicians may occasionally consider more holistic treatment plans that involve radioactive iodine and endocrine therapy.

Mesenteric desmoid fibromatosis entrapping metastatic urothelial carcinoma: a unique collision tumor or fibromatosis-like variant?

A collision tumor is a neoplastic lesion comprised of two or more distinct cell populations with distinct borders. Desmoid fibromatosis (DF) is a rare musculoaponeurotic tissue tumor that grows deep in the connective tissue and shows locally aggressive behavior. Only two cases of collision tumors with desmoid fibromatosis are reported in the English literature, albeit papillary thyroid carcinoma with desmoid fibromatosis-like stroma is regarded as a variant rather than a collision tumor. We present a unique case of collision tumor with desmoid fibromatosis surrounding intra-abdominal metastasis from urothelial carcinoma. A 65-year-old white male with history of bladder and left renal pelvis high-grade papillary urothelial carcinoma status post-nephrectomy was found to have a small bowel obstruction due to a soft tissue mass. Histology of the mass showed multiple matted lymph nodes with metastatic urothelial carcinoma admixed with a proliferation of spindle cells positive for nuclear beta-catenin, consistent with desmoid fibromatosis. While the prior surgical site likely acted as a nidus for development of desmoid fibromatosis, we also hypothesize that a dysregulation of beta-catenin signaling pathways within the cancer cells might have attributed to the spindle cell proliferation in the stroma surrounding the tumor. Our case emphasized the importance of clinical suspicion of desmoid fibromatosis in patients with metastatic cancer, requiring a prompt diagnosis and treatment to decrease the risk of complications and local recurrence.

Papillary Thyroid Carcinoma with Desmoid-Type Fibromatosis: Review of Published Cases

Simple Summary

Papillary thyroid cancer (PTC)-desmoid type fibromatosis (DTF) is one of the rarest variants of PTC. The diagnosis is histological, and detecting a mutation of CTNNB1 in the mesenchymal component is highly suggestive of PTC-DTF. The treatment is essentially surgical. We conducted a review of all cases of PTC-DTF found in the English literature and our aim is to describe patient’s characteristics, histology, immunohistochemistry and somatic mutations of every case.

Abstract

Desmoid-type fibromatosis (DTF) is a very rare variant of papillary thyroid carcinoma (PTC). It is essentially a dual tumor with a component of classical PTC with malignant epithelial proliferation (BRAF-mutated) and another component of mesenchymal proliferation (CTNNB1-mutated). We conducted a literature review on PTC-DTF. In total, 31 articles were identified, that together reported on 54 patients. The mean age was 47 years, with a 2.2:1 female predominance. No ultrasound features were found to be helpful in differentiating PTC-DTF from other PTC variants. Of the 43 cases that reported histological details, 60% had locally infiltrative disease (T3b or T4). Around 48% had cervical lymph node metastases, but none had distant metastases. While PTC-DTF may be locally more aggressive than classic PTC, its overall behavior is similar and can include extrathyroidal extension and lymph node metastases, which may contain a stromal component and show extranodal invasion. The mainstay of treatment for PTC-DTF is surgery, and the DTF component is not expected to be sensitive to radioactive iodine. External radiotherapy, non-steroidal anti-inflammatory drugs, tyrosine kinase inhibitors and chemotherapy have also been used in selected cases. Due to the rarity of these tumors and the lack of specific treatment guidelines, management should be discussed in a multidisciplinary team.

Papillary thyroid carcinoma with nodular fasciitis-like stroma: a rare variant

Papillary thyroid carcinoma with desmoid-type fibromatosis (PTC-DTF) or nodular fasciitis-like stroma (PTC-NFS) is a rare morphological variant of PTC with a favorable prognosis. There is a paucity of molecular data regarding this entity. We present the case of a 20-year-old female who presented with a palpable mass over the anterior aspect of the neck for the past 3–4 months, which was diagnosed as PTC-NFS. Ultrasonogram of the neck revealed a bulky left lobe of thyroid that contained a well-defined heterogenous lesion measuring around 24 × 26 × 36 mm with involvement of the adjacent isthmus. She underwent a total thyroidectomy with central compartment lymph node dissection. Histological examination revealed a biphasic tumor with epithelial and stromal components resembling nodular fasciitis. Two dissected lymph nodes showed metastasis of the epithelial component only. On immunohistochemistry, BRAF mutant protein expression was evident in the epithelial component only, while β-catenin was negative in both the components. The histopathological diagnosis of papillary thyroid carcinoma with nodular fasciitis-like stroma was offered. Sanger sequencing revealed a BRAFV600E (c.1799T>A, Val600Glu) mutation. Post-operatively, no residual tumor was detected on ultrasound and radioiodine scans. The patient was doing well at follow-up of 9 months. PTC-NFS/DTF is a histological variant of PTC with a favorable prognosis. Our index case was associated with the BRAF mutation, which was restricted to the epithelial component. Thorough sampling of the excised specimen is essential in order not to miss the epithelial component, which, in most reported cases (including ours) appears to be small.

The Involvement of the hsa_circ_0088494-miR-876-3p-CTNNB1/CCND1 Axis in Carcinogenesis and Progression of Papillary Thyroid Carcinoma

Recently, growing studies have demonstrated that circular RNAs (circRNAs) function as critical players in multiple human tumors, including papillary thyroid carcinoma (PTC). However, the expression and underlying potential mechanism of circRNAs in PTC are still not fully elucidated. In this study, 14 candidate differentially expressed circRNAs (DECs) between normal thyroid tissues and benign thyroid tissues or PTC were first screened using the GSE93522 dataset by the GEO2R online tool. Then, the structural loop graphs of these 14 circRNAs were obtained through the CSCD database. After performing miRNA co-prediction by combination of CSCD and CRI databases, a potential circRNA-miRNA sub-network, consisting of 9 circRNAs and 21 miRNAs, was successfully constructed. Subsequently, the expression and prognostic values of these miRNAs were further determined by starBase, and two miRNAs, namely, miR-605-5p and miR-876-3p, were identified as key miRNAs in PTC. Then, their downstream target genes were predicted by the miRNet database. CTNNB1 and CCND1 were found to be two most potential targets of miR-876-3p by combination of multiple in silico analyses, including protein–protein interaction (PPI), hub gene screening, correlation analysis, and expression analysis. Conclusively, we established a key hsa_circ_0088494-miR-876-3p-CTNNB1/CCND1 axis linked to carcinogenesis and progression of PTC, which may provide promising therapeutic targets in treating PTC in the future.

Pitfalls in Challenging Thyroid Tumors: Emphasis on Differential Diagnosis and Ancillary Biomarkers

Thyroid pathology encompasses a heterogenous group of clinicopathological entities including rare and diagnostically challenging neoplasms. The review is focused on morphological, immunohistochemical, and molecular features of rare thyroid neoplasms that can pose diagnostic problems. The tumors are organized based on growth patterns including thyroid neoplasms with predominantly papillary, follicular, solid, and spindle cell growth pattern, as well as neoplasms with distinct cytological characteristics. A special section is also dedicated to rare thyroid tumors with peculiar patterns including thyroid carcinoma with Ewing family tumor elements and intrathyroidal thymic-related neoplasms.

Papillary thyroid carcinoma with prominent myofibroblastic stromal component: clinicopathologic, immunohistochemical and next-generation sequencing study of seven cases

Papillary thyroid carcinoma with desmoid-type fibromatosis or nodular fasciitis-like stroma is an extremely unusual and poorly understood subtype of papillary thyroid cancer. Although prior studies have demonstrated alterations in the Wnt/β-catenin signaling pathway in some of these tumors, controversy still exists regarding the nature of the stromal spindle component. We have studied seven cases of papillary thyroid carcinoma with prominent myofibroblastic stroma, including six men and one woman aged 20-65 years (mean age = 44). All cases displayed areas consistent with conventional papillary thyroid carcinoma embedded in abundant myofibroblastic-like stroma. The myofibroblastic stroma in six cases resembled desmoid-type fibromatosis and in one case it more closely resembled nodular fasciitis. By immunohistochemical staining, the stromal spindle component showed positivity for SMA and low MIB1 proliferation index in all cases, and there was at least patchy strong nuclear positivity for beta-catenin in six/seven cases. Stains for cytokeratin AE1/AE3 and PAX8 were positive in the epithelial elements but negative in the stromal component. Next-generation sequencing was performed on six of seven cases. CTNNB1 gene mutations were identified in six/seven cases. The epithelial component showed BRAF mutations in two cases and an NRAS mutation in one case. The case with fasciitis-like stroma was negative for beta-catenin by sequencing and immunostaining as well as negative for USP6 gene rearrangement. Our findings indicate that papillary thyroid carcinoma with prominent myofibroblastic stroma may represent more than one category of lesions.