Clinicopathological and molecular study of 10 salivary gland clear cell carcinomas, with emphasis on rare cases with high grade transformation and occurring in uncommon sites

Hyalinizing Clear Cell Carcinoma of the Salivary Gland in an Elderly Female: A Case Report Supported by EWSR1 Molecular Studies

Hyalinizing clear cell carcinoma of the salivary gland is a rare neoplasm, accounting for only less than 1% of malignancies arising from the salivary gland. It is molecularly defined by the expression of the EWSR-ATF1 fusion oncogene. To date, there has been no previous studies published yet in the Philippines regarding the existence of this tumor. In this paper, we present a case of a 70-year-old elderly female who had a 10-year history of a gradually enlarging left lateral neck mass. Histopathologic examination showed a tumor arranged of cords, nests, and trabeculae of monomorphic round cells with abundant clear to lightly eosinophilic cytoplasm surrounded by thick hyalinized collagen bundles. Immunohistochemistry and molecular studies were done which revealed a positive p63 staining, negative SMA and S100, and an EWSR1 rearrangement in Fluorescence in situ hybridization (FISH), thus, confirming the diagnosis.

High-Grade Transformation and Carcinosarcoma: A Review of Two Forms of Advanced Progression in the Salivary Gland

CONTEXT.—

High-grade transformation, previously known as dedifferentiation, in salivary gland carcinoma and carcinosarcoma ex pleomorphic adenoma is a rare phenomenon. It is, however, clinically relevant and affects treatment and prognosis.

OBJECTIVE.—

To review the existing literature, describe the histologic and immunophenotypic features, and highlight the diagnostic criteria of high-grade transformation in various salivary gland carcinomas and carcinosarcomas; to review its effect on clinical presentation and prognosis; and to review relevant molecular characteristics and recent concepts and advances.

DATA SOURCES.—

Literature search in PubMed using key words such as "high-grade transformation," "dedifferentiation," and "carcinosarcoma" in salivary gland. Relevant articles were reviewed, and additional articles were curated from the references of these articles.

CONCLUSIONS.—

High-grade transformation occurs rarely but has a significant impact on prognosis and management. By microscopy, the high-grade area is usually a distinct nodule and shows solid and nested architecture, cellular atypia, high mitotic count, and necrosis. The molecular features are not well established. Carcinosarcoma almost always arises in a pleomorphic adenoma and likely follows an adenoma-carcinoma-sarcoma pathway.

Hyalinizing clear cell carcinoma of the sublingual gland: A case report and literature review

RATIONALE

Hyalinizing clear cell carcinoma (HCCC) of the salivary glands is a rare low-grade malignant tumor. This type of tumor is particularly uncommon in the sublingual glands.

PATIENT CONCERNS

A 57-year-old female with a mass on the left side of the floor of the mouth that had been present for 2 months. The computed tomography scan of the neck revealed a nodular abnormal density shadow in the left sublingual area, measuring approximately 2.6 cm × 1.9 cm.

DIAGNOSES

Primary HCCC of the sublingual gland.

INTERVENTIONS

The patient underwent surgical treatment and reconstruction using a left anterolateral femoral free flap, which showed immunohistochemical positivity for CK 5/6, CK 7, CK (AE1/AE3), and Ki-67 (<5%), but negative for SMA and S-100.

OUTCOMES

No recurrence was observed during the 12-month postoperative follow-up period.

LESSONS

The absence of characteristic clinical manifestations makes HCCC highly susceptible to misdiagnoses. This case presents a rare instance of HCCC in the sublingual gland, providing a reference for the clinical diagnosis and treatment of the disease.

High-grade transformation of head and neck adenoid cystic carcinoma demonstrates distinctive clinicopathological features and an unfavorable prognosis: a matched case-control study of the largest series in China

PURPOSE

Amidst the rarity of High-grade transformation (HGT) in adenoid cystic carcinoma (ACC), this study offers unprecedented insights into its aggressive nature and clinical implications.

METHODS

A 1:1 match comparison between 23 HGT patients and non-HGT counterparts was extracted from 412 ACC cases, focusing on dissecting distinctive clinicopathological features and prognostic outcomes.

RESULTS

The predominant sites of HGT were the sinonasal and lacrimal glands (30.4% each). Notably, the solid subtype was the most prevalent pattern within HGT, accounting for 69.6% of cases. Compared to non-HGT, the HGT cohort exhibited significantly higher rates of lymph node metastasis (39.1% vs. 8.7%; P < 0.05), perineural invasion (60.9% vs. 26.1%; P < 0.05), and increased Ki-67 proliferation index (35.0% vs. 10.0%; P < 0.05). Moreover, HGT regions typically showed reduced or absent p63 expression, along with high-grade pathomorphology. HGT was associated with increased recurrence (55.0%) and distant metastasis (78.3%), leading to an average survival of 35.9 months and a 3-years mortality rate of 35.0%. Overall and progression-free survival rates were significantly decreased in the HGT group.

CONCLUSION

This study represents the largest single-center cohort of HGT cases to our knowledge, highlighting its frequent occurrence in the sinonasal and lacrimal glands and association with poorer outcomes. The findings support classifying HGT in ACC as Grade 4, reflecting its severity.

Clinical and Histopathologic Analyses of Nasopharyngeal Hyalinizing Clear Cell Carcinoma: A Series of 26 Cases With Molecular Confirmation

The aim of this study was to evaluate the clinicopathologic features, molecular characteristics, treatment strategy, and prognosis of nasopharyngeal hyalinizing clear cell carcinoma (HCCC). Retrospective observational case series. Institutional pathology records between 2006 and 2022 were searched for all cases of nasopharyngeal HCCC. We included 10 male and 16 female patients aged 30 to 82 years (median: 60.5 y, mean: 54.6 y). The most common symptoms were blood-stained rhinorrhea and nasal obstruction. Tumors most often involved the lateral wall of the nasopharynx, followed by the superior posterior wall. Microscopically, all tumor cells were arranged in sheets, nests, cords, and single cells in a hyaline/myxoid/fibrous stroma. The tumor cells were polygonal, with or without distinct cell borders, and displayed abundant clear-to-eosinophilic cytoplasm. All 26 cases were positive for pancytokeratin, CK7, p40, and p63 but negative for myoepithelial differentiation markers. Ki-67 labeling was low and ranged from 1% to 10%. All 26 cases demonstrated EWSR1 and EWSR1-ATF1 rearrangements, and no case demonstrated MAML2 rearrangement. Complete follow-up data were available for 23 patients: 14 patients underwent endoscopic surgery alone, 5 underwent radiation therapy followed by endoscopic surgery, 3 underwent radiation therapy followed by biopsy, and 1 underwent cisplatin chemotherapy before endoscopic surgery. Clinical follow-up ranged from 6 to 195 months; 13 patients (56.5%) were alive without tumor, 5 patients (21.7%) died of disease, 5 patients (21.7%) survived with tumor. HCCCs of the nasopharynx are rare tumors. The definitive diagnosis depends on histopathology, immunohistochemistry, and molecular studies. The optimal treatment for patients with nasopharyngeal HCCC is wide local excision. Radiation and chemotherapy might be good options for managing locally advanced cases. Nasopharyngeal HCCC is less indolent than previously thought. Tumor stage and the choice of treatment are key factors affecting the prognosis of nasopharyngeal HCCC patients.

Histopathological Aspects of the Prognostic Factors for Salivary Gland Cancers

Salivary gland cancers (SGCs) are diagnosed using histopathological examination, which significantly contributes to their progression, including lymph node/distant metastasis or local recurrence. In the current World Health Organization (WHO) Classification of Head and Neck Tumors: Salivary Glands (5th edition), malignant and benign epithelial tumors are classified into 21 and 15 tumor types, respectively. All malignant tumors have the potential for lymph node/distant metastasis or local recurrence. In particular, mucoepidermoid carcinoma (MEC), adenoid cystic carcinoma (AdCC), salivary duct carcinoma, salivary carcinoma, not otherwise specified (NOS, formerly known as adenocarcinoma, NOS), myoepithelial carcinoma, epithelial-myoepithelial carcinoma, and carcinoma ex pleomorphic adenoma (PA) are relatively prevalent. High-grade transformation is an important aspect of tumor progression in SGCs. MEC, AdCC, salivary carcinoma, and NOS have a distinct grading system; however, a universal histological grading system for SGCs has not yet been recommended. Conversely, PA is considered benign; nonetheless, it should be cautiously treated to avoid the development of metastasizing/recurrent PA. The aim of this review is to describe the current histopathological aspects of the prognostic factors for SGCs and discuss the genes or molecules used as diagnostic tools that might have treatment target potential in the future.

Primary pulmonary hyalinizing clear cell carcinoma with pseudopapillary structures and abundant cysts filled with mucus

Pulmonary hyalinizing clear cell carcinoma (HCCC) is a new and rare form of lung salivary gland tumor. Only twenty-two cases have been reported in the literature to date. Furthermore, their clinicopathological features have not been fully characterized. In this paper, we describe the clinicopathological characteristics, immunohistochemical features, and molecular genetic changes in two HCCC cases. We also simultaneously reviewed related literature on similar cases reported. Of the two cases, one was of a 58-year-old man with a 4.3 cm lung tumor, which was the largest among all previously reported cases. The tumor showed an infiltrative growth pattern and perineural and vascular invasion microscopically. Moreover, nuclear grooves, high mitotic figures, and comedo necrosis were observed in addition to classic morphological features. More importantly, rare pseudopapillary structures were observed. The second case was of a 60-year-old woman in whom the tumor was mainly composed of multiple cysts filled with mucus. The remaining focal solid areas of the tumor comprised clear and acidophilic cells embedded in the hyalinizing stroma. Immunohistochemical analysis revealed that the tumor cells of both cases were positive for CK5/6, p40, and p63 expression, but negative for napsin A, TTF-1, and SOX10 expression. The HCCC diagnosis in both cases was validated by fluorescence in-situ hybridization (FISH) examination, which showed Ewing sarcoma breakpoint region 1-activating transcription factor 1 (EWSR1-ATF1) gene fusion. Primary pulmonary HCCC is a rare lung tumor originating from the bronchial mucosa, and its histological features may vary, such as rare pseudopapillary structures and abundant cysts. Thus, the diagnosis should be a combined analysis of histopathological characteristics with immunophenotype and molecular examination, including EWSR1-ATF1 gene fusion detection.