Hyalinizing clear cell carcinoma of the parotid gland: Report of a recurrent case with aggressive cytomorphology and behavior diagnosed on fine-needle cytology sample

Fine-needle aspiration cytology of adamantinoma-like Ewing sarcoma: An unusual parotid tumor

Adamantinoma-like Ewing sarcoma (ALES) is a histological subtype of Ewing sarcoma that demonstrates the morphological and immunohistochemical features of the latter, harbors the EWSR1::FLI1 gene fusion, and additionally demonstrates complex epithelial differentiation on morphology and immunohistochemistry. Accurate preoperative diagnosis has potential to inform management and improve patient outcome. Cytomorphology of ALES is not well documented, with available reports showing a spectrum of features. An aspirate from a 30-year-old male with a swelling in right parotid region, interpreted elsewhere as acinic cell carcinoma (ACC), was submitted to us for review. Smears showed dispersed cells and loosely cohesive clusters with scant cytoplasm and large nuclei with focal nuclear molding, prompting a diagnosis of malignant neoplasm, possibly neuroendocrine carcinoma. Cytoplasmic vacuoles and tigroid background were present focally, the former of which had possibly led to interpretation as ACC. No material was available for ancillary tests. Parotidectomy revealed features of ALES. The cytological features of ALES in the parotid overlap with several basaloid and round blue cell neoplasms that are more common at this site. ALES should be considered in all salivary gland aspirates with isomorphic small round or basaloid cells, with or without the presence of squamous differentiation. Rosettes, cytoplasmic vacuoles, and a tigroid background are subtle morphological clues to the diagnosis, which if suspected on cytomorphology, can be confirmed using ancillary techniques.

Clear cell carcinoma: a comprehensive literature review of 254 cases

This comprehensive literature review represents a summary of all cases of clear cell carcinoma (CCC) of the salivary glands that are documented in the literature. PubMed was used to collect available reports of CCC; 97 reports detailing 254 cases, published between 1983 and 2020, were retrieved. Clinically the tumor manifests most commonly as a painless mass or swelling on the palate, and the duration of symptoms prior to seeking care ranges from 1 week to 6 years. Local tumor recurrence was present in 18.8% of the cases. By histopathology, CCC shows a mixture of growth patterns including solid (25.1%), nested (78.6%), sheet-like (23.5%), cords (46.1%), and trabeculae (42.4%). Immunohistochemical studies are positive for one or more cytokeratins (99.1%), PAS (95.1%), EMA (77.8%), and p63 (96.3%), but negative for S-100 (96.3%), PASD (91.1%), SMA (91.0%), and calponin (95.1%). Molecular features were reported in 113 cases; 96.0% were positive for an EWSR1 rearrangement by EWSR1 break apart FISH testing and 14.8% were positive for the rearrangement EWSR1-ATF1 tested by qPCR or targeted RNA sequencing. Clinical patterns and genetic studies imply that this tumor is the extraosseous counterpart of clear cell odontogenic carcinoma, an intraosseous odontogenic tumor of the jaws.

Does Nodal Metastasis and Perineural Invasion Affect Local Control in Hyalinizing Clear Cell Carcinoma of the Oral Cavity? A Case Report with Long Term Follow-Up

Hyalinizing clear cell carcinoma (HCCC) is a rare, low-grade neoplasm accounting for approximately 1% of salivary gland neoplasms. Histologically, it is characterized by a monomorphous population of clear cells arranged in sheets, nests, or cords, lacking ductal structures. Until recently, clear cell carcinoma of the oral cavity (OC) represented a diagnosis of exclusion when other head and neck pathologic entities such as epithelial-myoepithelial carcinoma or mucoepidermoid carcinoma could be ruled out, making definitive diagnosis by light microscopy and immunoprofiling a challenge. As a result, initial biopsies are often misclassified, and could result in under- or overtreatment. More recently, the presence of the EWSR1-ATF1 gene fusion has been adopted to definitively diagnose HCCC. Typically, HCCC demonstrates clinical indolence and responds well to curative surgical excision alone for localized disease, with adjuvant radiotherapy (RT) reserved for high risk features including perineural invasion, lymphovascular invasion, and regional cervical metastasis. The literature, however, lacks consensus regarding the role of adjuvant radiotherapy. In this article, we report a case of HCCC in a rare site involving the ventral tongue, with high risk features of perineural invasion and cervical nodal metastasis. The patient underwent surgical excision alone; declining adjuvant radiotherapy despite the high risk features, and was alive with no evidence of disease at the 42-month mark. Furthermore, we provide an update on the current prognostic indicators for HCCC, and emphasize the need for chromosomal analysis to achieve a definitive diagnosis.

Ancillary testing in salivary gland cytology: A practical guide

Salivary gland cytology is challenging, and historically the role of ancillary testing has been limited. However, numerous molecular/genetic advances in the understanding of salivary gland neoplasms during the last decade have facilitated the development of many useful diagnostic markers, such as PLAG1 and HMGA2 immunohistochemistry for pleomorphic adenoma and ETV6 fluorescence in situ hybridization for secretory carcinoma. Numerous salivary gland neoplasms are characterized by specific molecular/genetic alterations, many of which can be identified on cytologic preparations by karyotype analysis, fluorescence in situ hybridization, or immunohistochemical surrogates. Next-generation sequencing also has potential diagnostic applications, although to the authors' knowledge it currently has no routine role in salivary cytology. The primary goal of salivary fine-needle aspiration (FNA) is to facilitate appropriate clinical management. Ancillary testing has greatly enhanced the ability for accurate classification as per The Milan System for Reporting Salivary Gland Cytopathology and allows for the definitive diagnosis of many salivary FNA specimens, and also may resolve diagnostic uncertainty for FNAs that may be classified in The Milan System for Reporting Salivary Gland Cytopathology categories of salivary gland neoplasm of uncertain malignant potential or suspicious for malignancy. This review provides an updated discussion of the molecular/genetic features of the more commonly encountered salivary neoplasms by FNA, and discusses the application of available diagnostic immunohistochemical and molecular tests in salivary gland cytology.

The key radiologic and cytomorphologic features of oncocytic and oncocytoid lesions of the salivary gland

Oncocytic and oncocytoid lesions represent a distinct subset of salivary gland lesions. True oncocytic lesions of the salivary gland are entirely composed of oncocytes. These are characterized by the presence of abundant eosinophilic granules due to the presence of abundant cytoplasmic mitochondria. Oncocytic lesions of the salivary gland include oncocytosis, oncocytoma, and oncocytic carcinoma. In addition to the true oncocytic lesion, there exists another group of salivary gland lesions, which demonstrate cells with abundant and occasionally granular cytoplasm. These are often termed as "oncocytoid" lesions. The recently proposed Milan System for reporting salivary gland cytology clearly states that fine-needle aspiration specimens representing oncocytic/oncocytoid lesions of salivary gland cannot effectively distinguish between a nonneoplastic lesion, benign and malignant neoplasms. Therefore, most lesions lacking classic cytomorphologic features will be classified under the umbrella diagnostic term of "Salivary Gland Neoplasm of Uncertain Malignant Potential" (SUMP). In this review, we discuss and illustrate key clinicopathologic and radiologic features that can help the practicing cytopathologist narrow down the differential and provide the best management based diagnosis.

Hyalinizing clear cell carcinoma of salivary glands: A retrospective study focused on uncommon morphology, immunohistochemistry, and detection of gene fusion using fluorescence in situ hybridization

AIMS

To investigate histological, immunohistochemical, and molecular features, especially uncommon morphology of hyalinizing clear cell carcinoma (HCCC) to expand the morphological spectrum of HCCC.

METHODS AND RESULTS

We examined 5 cases of HCCC by histological, immunohistochemical, and molecular analysis. Generally, 5 HCCC cases shared similar characteristics, exhibiting clear to slightly eosinophilic cells arranged in cords, nests, islands, or trabeculae with a hyalinized stroma, while myxoid stroma, perineural invasion, and polygonal cells with high-grade nuclei were observed in 3 cases. Immunohistochemically, 5 cases were entirely immunoreactive for CKpan, whereas 80% HCCC cases were positive for P63, and CK14. None expressed immunoreactivity for S-100, Calponin, or GFAP. The positive rate of Ki-67 staining was about 5% in the classic area of case 3, but 40% in the high-grade area. As for the result of FISH findings, EWSR1 gene break was detected in all 5 HCCC cases.

CONCLUSIONS

Our study has expanded the morphological spectrum of HCCC, and proposed the diagnosis of HCCC should be confirmed by fully analyzing histological, immunohistochemical, and molecular features practically.

Cystic major salivary gland lesions: Utilizing fine needle aspiration to optimize the clinical management of a broad and diverse differential diagnosis

INTRODUCTION

The use of fine-needle aspiration (FNA) cytology for the preoperative evaluation of salivary gland lesions is an accepted but, currently, nonstandardized practice. More specifically, cystic major salivary gland lesions are relatively rare and can be very challenging to diagnose on FNA due to low cellularity and an incredibly broad differential diagnosis. The purpose of this study was to investigate the diagnostic utility of preoperative FNA cytology for cystic major salivary gland lesions.

METHODS AND MATERIALS

The electronic pathology archives of The Johns Hopkins Hospital were searched to identify FNA specimens of cystic major salivary gland lesions over a 15 year period (January 1, 2000 to December 21, 2015). The age, race, sex, biopsy site, use of ultrasound guidance, cytopathologic diagnosis, and presence or absence of clinical follow-up were recorded for each patient. Cases were divided into those with and without follow-up. Diagnostic performance between FNA and follow-up data were recorded.

RESULTS

A total of 145 cases met the inclusion criteria, while 123 (84.8%) patients had follow-up data available. Of these patients, 67.5% underwent FNA as the only pathologic diagnostic modality. Sensitivity, specificity, positive predictive value, and negative predictive value for the detection of cystic neoplasms were 41.6%, 99.0%, 90.9%, and 87.6%, respectively. For cases containing mucin, 100.0% sensitivity and specificity were achieved.

CONCLUSION

FNA of cystic salivary gland lesions is a useful clinical decision-making tool that can reduce the number of patients ultimately requiring surgical excision. Although specificity is high, a relatively low overall sensitivity makes clinical and radiologic correlation imperative.

Hyalinizing Clear Cell Carcinoma with Biopsy-Proven Spinal Metastasis: Case Report and Review of Literature

BACKGROUND

Hyalinizing clear cell carcinoma (HCCC) is a rare epithelial malignant neoplasm typically arising from the minor salivary glands. Although it has been described as a benign neoplasm, there are increasing reports of malignant features and metastases to the lungs; we present the first case of biopsy-proven spinal metastases from HCCC and an overview of the literature.

CASE DESCRIPTION

This is a single-patient case report in which we used immunohistochemistry and fluorescence in situ hybridization for Ewing sarcoma breakpoint region 1 translocation to confirm the diagnosis of HCCC in a spinal metastasis. The diagnosis of metastatic HCCC was confirmed on the basis of histopathology, immunohistochemistry, and fluorescence in situ hybridization studies.

CONCLUSIONS

We present the first pathologically confirmed case of a spinal metastasis in HCCC. As increasing of metastatic HCCC arise, a reconsideration of HCCC as a potentially high-grade disease seems increasingly necessary as it may impact the current treatment paradigm.

Nasopharyngeal hyalinizing clear cell carcinoma with EWSR1 rearrangements diagnosed by fluorescence in situ hybridization

Hyalinizing clear cell carcinoma (HCCC) is a rare, low-grade salivary gland neoplasm with a predilection for the palate and tongue. A 63-year-old woman presented a 14×14×17-mm mass at the roof of the nasopharynx. Endoscopic resection was performed via a transnasal approach. Histopathological findings of the salivary gland tumor indicated hyalinization of the stroma and neoplastic cells with clear cytoplasm without mucin. Fluorescence in situ hybridization analysis revealed that the tumor cells were positive for EWSR1 rearrangement. We finally diagnosed this case as HCCC of the nasopharynx. EWSR1 rearrangements are non-existent in other salivary gland tumors with clear cell change; thus, the identification of this rearrangement was very useful in accurately diagnosing HCCC.

Very delayed cervical lymph node metastases from hyalinizing clear cell carcinoma: report of 2 cases

BACKGROUND

Hyalinizing clear cell carcinoma (HCCC) is a rare salivary gland neoplasm most often found in the oral cavity. Although it is generally a low-grade malignancy that is treated with wide local excision, there is a growing body of evidence pointing toward the potential for more aggressive behavior.

METHODS

We reviewed available records of patients with delayed cervical lymph node metastases from HCCC.

RESULTS

Two patients who were treated with wide local resection for HCCC and remained disease-free at the primary site were diagnosed with cervical lymph node metastases 10 and 14 years later. We treated both with neck dissection, and 1 patient received adjuvant radiation therapy.

CONCLUSION

These cases illustrate the risk for occult nodal metastases from HCCC with delayed presentation. Clinician awareness of the presence of subclinical metastases in the neck requires thorough long-term surveillance and potential intervention should nodal disease become manifest.

Envisioning the next WHO head and neck classification

The next WHO classification should abandon "salivary duct carcinoma"; conventional salivary duct carcinoma should be classified as "high-grade salivary duct carcinoma". Low-grade salivary duct carcinoma should replace the current nosology of "low-grade cribriform cystadenocarcinoma". Cystadenocarcinoma should be classified with the descriptor "Not Otherwise Specified" and should be considered an exclusionary diagnostic category. On the other hand, "Not Otherwise Specified" does not fit for hyalinizing clear cell carcinoma (HCCC). The EWSR1-ATF1 fusion is specific for HCCC within the context of salivary neoplasia. We recommend adding "hyalinizing" even though this feature is not present in all cases; the benefit of which is the mental association with a salivary clear cell malignancy. Sinonasal Renal Cell-like Adenocarcinoma (SNRCLA) is a distinct clear cell neoplasm and should be added to the next WHO classification. Future studies will bear out whether SNRCLA is even a low-grade carcinoma, or may be reclassified as "adenoma". Lastly, the next WHO monograph should include the Risk Model in the general introductory statements on oral squamous cell carcinoma, under a subheading of "Histological Prognosticators". The positive predictive value for developing locoregional recurrence in patients with low-stage oral cavity squamous carcinoma (OSCC) and "worst pattern of invasion type-5" (WPOI-5) is 42 %. Low-stage high-risk OSCC with a combination of features other than WPOI-5 is associated with 32 % likelihood for locoregional progression. WPOI-5 also predicts occult metastatic disease (p = 0.0001, Chi squared, 2 DF). Thus the Risk Model can also be used to make decisions regarding staged elective neck dissections.