Clear cell carcinoma of the palate

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.

Recent updates in salivary gland tumors of the lung

Salivary gland tumors are uncommon primary lesions in the lung. Their morphologic, immunophenotypic, and molecular characteristics resemble those of their counterparts in the head and neck or elsewhere. Most common primary pulmonary salivary gland tumors include mucoepidermoid carcinoma, adenoid cystic carcinoma, and epithelial-myoepithelial carcinoma. The study of these neoplasms is hampered by their paucity. Therefore, studies are in general small or restricted to individual cases. Despite this challenge recent advances have been made specifically at the molecular level. Molecular alterations such as MAML2 rearrangements in mucoepidermoid carcinoma, MYB rearrangements in adenoid cystic carcinomas, and EWSR1 rearrangements in hyalinizing clear cell carcinomas and myoepithelial tumors have been identified. These molecular alterations might be helpful in the distinction of these salivary gland tumors from other neoplasms in the lung. However, the distinction from metastatic disease remains challenging. Awareness of these tumors and knowledge of available ancillary studies to confirm the diagnosis is important to avoid misdiagnosis which might lead to differences in treatment, management, and prognosis. Further studies are needed to identify biomarkers to better predict patient's outcome and for individual management and treatment of patients.

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.

Glycogen-Rich Clear Cell Squamous Cell Carcinoma Originating in the Oral Cavity

Clear cell squamous cell carcinoma (CCSCC) is a rare histological subtype of squamous cell carcinoma (SCC) that was originally described in the skin. Here, we report a case of a 66-year-old female patient who presented with a fungating ulcerative mass of the left lateral tongue extending anteriorly to the floor of the mouth, and posteriorly to the left retromolar fossa and the oropharynx. The patient had a history of SCC of the left posterior tongue that was treated with partial glossectomy and adjuvant radiotherapy. Representative biopsies were obtained from the floor of the mouth, tongue and retromolar fossa. The examined biopsies showed various degrees of dysplastic surface epithelium with transition into infiltrating epithelial tumor nests and cords with clear cytoplasm and malignant cellular features. Pancytokeratin, CK5/6, and p63 were all diffusely positive. S-100, Calponin, and smooth muscle actin (SMA) were negative. PAS stain was diffusely positive and diastase labile in the tumor clear cells. Sparse areas of mucicarmine positivity were noted. Based on these findings a final diagnosis of a glycogen-rich CCSCC was given. This case represents a very rare histological variant of oral SCC, which is significant for the histological differential diagnosis of clear cell tumors of the oral cavity.

A Case of Hyalinizing Clear Cell Carcinoma, So-Called Clear Cell Carcinoma, Not Otherwise Specified, of the Minor Salivary Glands of the Buccal Mucosa

Hyalinizing clear cell carcinoma (HCCC), so-called clear cell carcinoma, not otherwise specified (CCC (NOS)), of the salivary glands is a rare and low-grade malignant tumor. We report a case of HCCC so-called CCC (NOS) (referred to as HCCC) of the minor salivary gland of the buccal mucosa. A 52-year-old woman had presented with a gradually growing and indolent mass in the right buccal mucosa for about two years. The first biopsy histopathologically suggested the possibility of malignancy derived from the minor salivary glands. A month later, she visited our hospital. The tumor measured approximately 1.5 cm in diameter and was elastic hard, smooth, and well movable. Image examinations demonstrated internal homogeneity of the lesion, which had a smooth margin, in the right buccal mucosa. Complete tumor resection followed by covering with a polyglycolic acid sheet and fibrin glue spray was performed without surgical flap reconstruction. Histopathological findings revealed proliferating tumor cells with clear cytoplasm surrounded by hyalinizing stroma in the submucosal minor salivary glands. Immunohistochemical stains revealed these tumor cells to be positive for epithelial cell markers but negative for myoepithelial ones. These findings confirmed the diagnosis of HCCC. Good wound healing and no evidence of local recurrence and metastasis have been shown since surgery.

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.

Primary glycogen-rich clear cell squamous cell carcinoma of the mandibular gingiva

Clear cell squamous cell carcinoma (CCSCC) is a rare variant of squamous cell carcinoma, first reported by Kuo, who described 6 cases of squamous cell carcinoma of the skin of the head and neck. CCSCC is composed of cells with clear cytoplasm, which Kuo attributed to the accumulation of intracellular fluid and not the presence of glycogen, lipid, or mucin. This case describes a 59-year-old woman who presented with an exophytic, hemorrhagic lesion on the posterior mandibular gingiva of 2 months' duration. Histologic examination revealed dysplastic stratified squamous epithelium showing transition to an infiltrating tumor composed of islands of epithelial cells with clear cytoplasm. The cytoplasm stained positive with periodic acid Schiff but was diastase labile. Mucicarmine stains were negative for intracytoplasmic mucin. This is the first reported case describing primary glycogen-rich CCSCC of the mandibular gingiva.

Hyalinizing clear cell carcinoma: a case report and review of the literature

Hyalinizing clear cell carcinoma (HCCC) is a low-grade malignancy with infiltrative growth pattern. It affects mainly the minor salivary glands of adult women. The most frequent locations of this tumor are the palate and tongue. HCCC shows a poorly circumscribed, infiltrative, and essentially monomorphic population of clear cells with few mitoses and almost no nuclear or cellular pleomorphism. These cells form trabeculae, cords, islands, and/or nests, circumscribed by variable amounts of hyalinized fibrous bands with foci of myxohyaline stroma. S-100 protein, muscle-specific actin, smooth muscle actin, myosin, and calponin are consistently negative, which strongly indicates the absence of myoepithelial cell differentiation in this tumor. We present a case of HCCC affecting the upper vestibule in a 53-year-old man. The patient was treated by surgery and postoperative radiation and did not show recurrence or distant metastases 3 years after treatment. Discussed also are the clinical and pathologic features of this tumor along with the differential diagnosis and a literature review.

Clear cell adenocarcinoma of the base of the tongue: a case report and review of the literature

Clear cell adenocarcinoma is an extremely rare tumor of the head and neck region. We report a case of a 75-year-old Caucasian woman with a 10-day history of hemoptysis but with no pain or other significant symptoms. A head and neck computed tomography scan with contrast medium showed an irregular, soft-tissue-like, irregularly enhanced lesion of the base of the tongue extending to its posterolateral portion. The tumor reached the lateral wall of the oropharynx, which showed a nonhomogeneous aspect. The patient underwent resection of the tumor via a conservative transmandibular approach. A clear cell adenocarcinoma of the base of the tongue is rarely a primary malignant lesion; it is more frequently a secondary lesion from a metastatic renal tumor. Because of this neoplasm's relatively slow growth rate and low incidence of metastasis or local recurrence, the gold standard of treatment is complete excision of the tumor with a sufficient tumor-free margin.

Clear cell carcinoma of the minor salivary gland: an autopsy case with multiple metastases 29 years after the initial surgery and a review of the literature

Clear cell carcinoma of the salivary gland is an uncommon tumor comprising about 1% of neoplasms of minor salivary glands. We report an autopsy case of a tumor with widespread metastases 29 years after initial surgery. At the initial presentation, the patient was a 48-year-old man with a small ulcerative tumor in the right hard palate, and the tumor was excised. Twenty-four years after the initial excision, the first recurrence was detected in the lung. Five years later, the patient died of widespread metastases of the disease at the age of 77. Specimens obtained at the initial excision and at autopsy were very similar histologically and immunohistochemically, and both were clear cell carcinoma of the salivary gland. The patient died of the disease after a very long disease-free period, which reinforces the classification of this tumor as a low-grade malignancy.

Hyalinizing clear cell carcinoma: report of eight cases and a review of literature

Hyalinizing clear cell carcinoma (HCCC) is an extremely rare neoplasm with a female predominance, composed of nests of monomorphic clear cells within a hyaline stroma. This tumor often follows an indolent course and treatment includes wide surgical excision with or without adjuvant radiotherapy. We report eight cases of HCCC identified at two academic institutions in six women and two men, ranging in age from 25 to 86 years. Histologically, all cases demonstrated cords, trabeculae, and nests of monomorphic clear cells as well as cells with eosinophilic granular cytoplasm. Mild cellular atypia was occasionally seen and mitoses were very rare. Seven cases demonstrated a hyalinized stroma, and one case, a myxoid stroma. Immunohistochemically, the tumor cells were positive for epithelial markers and negative for desmin and actin. Seven cases were negative for S-100. Cells were also positive for periodic acid-Schiff and negative for mucin. The important clinicopathologic features and the differential diagnoses of HCCC, as well as a review of the literature are discussed.

Clear cell carcinoma: review of its histomorphogenesis and classification as a squamous cell lesion

In current classification schemes, clear cell carcinoma-including both the hyalinized and nonhyalinized variety--is now an accepted subtype of malignant salivary gland tumors. Despite this, the underlying cellular differentiation process leading to the typical histomorphology of this neoplasm remains unclear. This review summarizes and illustrates the histologic, ultrastructural, and immunohistochemical evidence for the underlying squamous cell nature of clear cell carcinoma. Squamous cell differentiation is not an uncommon feature of nonneoplastic and neoplastic lesions of the salivary glands. Clear cell carcinoma needs to be added to this list as a unique but specific variety of clear cell squamous carcinoma.

Hyalinizing clear cell carcinoma: case series and comprehensive review of the literature

BACKGROUND

Hyalinizing clear cell carcinoma (HCCC) is an uncommon malignant salivary gland tumor that was characterized only recently as a distinct entity. Because of its histologic similarity to several other primary and metastatic tumors and its purported favorable clinical outcome after local resection, it is important to recognize the features of this unusual tumor.

METHODS

The authors present 8 new, fully characterized cases of HCCC and systematically reviewed 44 other cases of HCCC reported in the English language literature from 1980 to 2008. Historic cases were reviewed, and available data regarding morphology, special stains, demographics, clinical presentation, radiographic findings, management, and outcomes were extracted. Data from the current series were compared with the earlier published literature.

RESULTS

To the best of the authors' knowledge, this was the largest reviewed series of HCCC and included a total of 52 cases. The findings, which included key histologic features, clinical presentation, and outcome, generally were consistent with what was reported previously. However, the current review revealed that 25% of patients reported in the literature had metastatases at initial presentation, including 10 of 44 patients who had metastases to regional lymph nodes and 1 patient who had metastasis to the lung. The authors were unable to identify any specific histologic features that would predict this behavior.

CONCLUSIONS

The current results indicated that HCCC is less indolent than was believed previously; therefore, regional lymph node dissection should be considered in conjunction with wide local excision for patients with HCC.

Clear cell carcinoma, not otherwise specified, of salivary glands: a clinicopathologic study of 4 cases and review of the literature

Clear cell carcinoma, not otherwise specified (CCC-NOS), is a recently described rare malignant salivary neoplasm. We report the clinicopathologic and immunohistochemical features of 4 cases. The results were then analyzed collectively with the approximate 60 cases of CCC-NOS reported in the English-language literature to define the characteristics of this unusual neoplasm. Combining our cases with those in the literature, a total of 66 cases, confirms that CCC-NOS is a low-grade malignant neoplasm with distinctive clinical and pathologic features. It arises primarily in the minor salivary glands (91% of cases), particularly in the palate or base of tongue, and usually occurs in patients >30 years of age (mean 54.2 years) with a female-to-male ratio of 1.4:1; 12.3% of patients experience local recurrences, 19.3% develop positive regional lymph nodes, 8.8% have distant metastases, and 3.5% die of the disease. Immunohistochemical study focusing on tumor differentiation was performed for our cases, and the findings support the concept that CCC-NOS is of ductal epithelial origin without myoepithelial cell participation.

Hyalinizing clear cell carcinoma of the base of tongue

Hyalinizing clear cell carcinoma is a rare, low-grade neoplasm of the minor salivary glands. It is composed exclusively of epithelial cells with optically clear cytoplasm. There are only a few isolated cases reported in the literature involving the base of tongue. The treatment of choice is wide excision and selective neck dissection, with or without radiotherapy. The prognosis of these tumours is good. A 57-year-old male patient presented with a lesion in the base of tongue, which was well enhanced on contrast computerized tomography scan. Once confirmed by biopsy, the hyalinizing clear cell carcinoma was resected via a transcervical approach. The patient underwent postoperative radiotherapy. There was no evidence of locoregional recurrence or distant metastasis at 18 months of follow up.