Clear-cell variant of squamous cell carcinoma in maxilla as primary lesion: A rare case

Decoding the Rarity: A Unique Case of Clear-Cell Variant of Oral Squamous Cell Carcinoma

The clear-cell variant of oral squamous cell carcinoma is an extremely rare histological variant and an incompletely understood entity. Clear cell appearance in squamous cell carcinoma may be attributed to hydropic degeneration of neoplastic cells. We report a case of a 32-year-old male patient who presented with an ulceroproliferative growth in the left maxillary posterior region on the hard palate and gingiva, obliterating the buccal vestibule. Histopathologic examination revealed thick anastomosing strands of round to ovoid neoplastic cells with predominantly clear cytoplasm and marked cellular and nuclear pleomorphism infiltrating into the fibro-cellular connective tissue stroma. Special staining and immunohistochemistry (IHC) were performed to rule out the differentials of clear-cell variants of different sites such as salivary gland, odontogenic origin, and metastatic tumors. The clear cells were negative for periodic acid Schiff (PAS) and mucicarmine. The malignant clear cells showed positive reactions with IHC markers pan-cytokeratin and P63 and yielded negative results for S100 and CD10, confirming the diagnosis as a clear-cell variant of oral squamous cell carcinoma. We emphasize the importance of prompt and comprehensive diagnostic work-up to identify this rare, aggressive, and possibly fatal neoplasm.

Clear cell oral squamous cell carcinoma as a diagnostic conundrum: report of 2 rare cases

The occurrence of clear cell histologic sub-type of oral squamous cell carcinoma in the oral cavity is a distinct and exceedingly rare entity exhibiting aggressive behavior. To date, only 10 cases have been published in the literature. We describe 2 extremely rare cases, both presenting with swelling and ulcerated nodule-like proliferative growth in the mandible. Microscopically, sheets and lobules of neoplastic squamous epithelial cells showing clear cell differentiation were appreciated in both patients. Periodic acid-Schiff and mucicarmine revealed negative staining. Immunohistochemical (IHC) analysis for antibody for renal cell tumor marker CD 10 was immune-negative. The malignant clear cells in both cases showed intense positive reactions with IHC markers pan-cytokeratin and epithelial membrane antigen, confirming the diagnosis as a clear cell variant of oral squamous cell carcinoma (CCOSCC). The first patient was unwilling for treatment and eventually died within 2 months of the diagnosis. In the second patient, right hemi-mandibulectomy with level 1A and 1B lymph nodes was performed. Adjuvant chemotherapy with low-dose methotrexate was initiated. Follow-up after 2 months of surgery was uneventful. Current rare reports emphasize the significance of prompt and extensive diagnostic work-up of clear cell neoplasms, as the CCOSCC may be fatal.

Clear Cell Squamous Cell Carcinoma of the Maxillary Gingiva Associated with PIK3CA and HRAS Mutations: Report of a Case and Literature Review

BACKGROUND

Squamous cell carcinoma (SCC) is the most common oral malignancy, and somatic mutations in some driver genes have been implicated in SCC development. Clear cell SCC (CCSCC) is a rare histological variant of SCC, and various clear cell neoplasms must be considered in the differential diagnosis of CCSCC in the oral cavity. Based on a limited number of CCSCC cases reported in the oral cavity, CCSCC is considered an aggressive variant of SCC with a poor prognosis; however, its genetic characteristics remain unknown.

METHODS

A maxillary gingival tumor in an 89-year-old female was described and investigated using immunohistochemical staining, special staining, fluorescence in situ hybridization, and next-generation sequencing (NGS) with a custom panel of driver genes, including those associated with SCC and clear cell neoplasm development.

RESULTS

Histopathological examination revealed a proliferation of atypical epithelial cells with abundant clear cytoplasm and enlarged and centrally placed round nuclei. The tumor was exophytic with deep, penetrating proliferation. The atypical clear cells were continuous with the conventional SCC cells. Immunohistochemical analysis showed that the clear cells were positive for CK AE1/AE3 and CK5/6 and nuclear-positive for p63. In contrast, the clear cells were negative for αSMA, S100, HMB45, Melan-A, CD10, and p16. p53 immunoreactivity exhibited a wild-type expression pattern. Additionally, the clear cells were positive for periodic acid-Schiff (PAS) and negative for diastase-PAS, mucicarmine, and Alcian blue. Based on these results, the diagnosis of CCSCC was confirmed. Molecular analysis of the clear cells identified PIK3CA p.E542K (c.1624G>A) and HRAS p.G12A (c.35 G>C) somatic mutations classified as oncogenic. No pathogenic variants were identified in TP53, EWSR1, AKT1, PTEN, BRAF, KRAS, NRAS, RASA1, or MAML2.

CONCLUSIONS

We report a case of CCSCC of the oral cavity with PIK3CA and HRAS mutations. The identification of PIK3CA and/or HRAS mutations is rare in SCC; however, both mutations are important potential targets for antitumor therapy. A detailed analysis of gene mutations in CCSCC may lead to a better understanding of its biological behavior and an improved prognosis, as well as a differential diagnosis from other clear cell neoplasms.

Acantholytic oral squamous cell carcinoma with clear cell change - a rare amalgamated variant

Background

Acantholytic squamous cell carcinoma (ASCC) is an uncommon histological variation of oral squamous cell carcinoma (OSCC), accounting for fewer than 4% of all occurrences. The tumor shows a slight masculine predisposition, with the lower lip being the most commonly affected location. ASCC is reported to have a diverse biologic behavior, which explains its ability to metastasize to distant places and, thus, its poor prognosis. Similarly, clear cell change in OSCC is a rare occurrence with an unknown etiology that suggests its aggressive nature.

Method and Results

Histopathology reveals central acantholytic cells with numerous duct-like features. The presence of distinct cytological atypia contributes to the diagnosis of SCC. Special stains and IHC aid in distinguishing tumor from other histopathologically similar entities.

Conclusion

The case of a 29-year-old male presented here with an updated literature review highlights the need for histological study of the unique and seldom seen oral ASCC with clear cell change, which can be ignored because of similarities with other entities. Because recurrence rates are so high for ASCC, amalgamated clear cell change makes it critical for proper treatment initiation with a definite diagnosis. To the best of our knowledge, this is the first documented occurrence. Our experience with the present case suspected a more aggressive behavior due to a high Ki-67 index, anticipating a poorer prognosis in the oral cavity considering the patient's young age.

Do Clear Cell Changes in Oral Squamous Cell Carcinoma Warrant It Being Recognised as a Variant?

Histological variants of oral squamous cell carcinoma (OSCC) include verrucous, basaloid, spindle cell, adenosquamous, papillary, and acantholytic types. Clear-cell changes in OSCC are rare.

We report a case of a 65-year-old male Chinese patient who presented with a swelling in the lower-left mandible for three weeks, causing ill-fitting of his lower denture and an ulcer on the floor of the mouth. Histologically, the lesion showed a dense proliferation of malignant tumor cells arranged in islands and sheets consisting of squamoid cells intermixed with signet ring-shaped clear cells. The clear cells were negative for mucicarmine, periodic acid Schiff (PAS), periodic acid Schiff-diastase (PAS-D), and alcian blue (AB). Immunohistochemistry showed the tumor cells were immuno-positive for cytokeratin (CK) and p63, but CK7, CK20, and S100 were immuno-negative. Therefore, a metastatic tumor in the oral cavity was suggested. However, the CT scan did not show any primary tumors in other sites. Histopathologically, the surgical specimen showed signet-ring-shaped clear cells in the stroma with squamoid cells invading the underlying connective tissue from the surface epithelium, suggesting a diagnosis of clear cell changes in OSCC. Follow-up showed recurrent OSCC at the base of the tongue with lymph node metastasis and distant metastasis in the lung.

Only a few cases of clear-cell changes have been reported, with most having a poor prognosis. This case report adds one more case of clear cell changes in the OSCC with a poor prognosis. We reviewed the literature to understand their clinical behavior. Due to the rarity of its (clear cell changes) occurrence, further research is required in order to obtain a better understanding of the clinical behavior and prognosis of these clear cell changes seen in OSCC.

Oral metastatic clear-cell tumours: To and fro: Unusual case reports

We report two extremely rare cases of metastatic clear-cell carcinomas, which metastasized from and to the oral cavity and both presented clinically in the oral cavity. First case was a primary lesion in the oral cavity, which showed distant metastatic deposits in liver, kidney, bone and brain. Histopathologically, lobules of pleomorphic clear cells were evident descending from the overlying mucosa, raising the suspicion of renal cell carcinoma. Immunohistochemical staining for CD10 was negative and the case was diagnosed as clear-cell type of oral squamous cell carcinoma which had disseminated to distant organs. In the second case, dysplastic clear granular cells were seen invading the bone. Immunohistochemical staining for CD10 showed focal mild positivity, confirming the diagnosis as clear-cell renal carcinoma which had metastasized to the oral cavity. Metastatic tumours must be considered in the differential diagnosis of rapidly growing ulcero proliferative lesions in the oral cavity.

Malignant lesion of clear cells: A diagnostic challenge of an unusual presentation mimicking a benign lesion

In the oral cavity, a broad spectrum of differential diagnostics includes lesions composed of clear cells. Under this umbrella, Clear Cell Odontogenic Carcinoma (CCOC) and Hyalinizing Clear Cell Carcinoma (HCCC) are rare malignancies that arise from different histological origins. However, the histology is similar; therefore, differentiation of CCOC and HCCC lesions is difficult and, in some cases, impossible to distinguish morphologically and immunohistochemically. Herein, we report an unusual presentation of a well-defined nodular lesion affecting the maxillary gingiva in a 19-year-old female, which presented clinically as a benign or reaction etiology lesion. Microscopic evaluation showed a tumor composed of cell sheets with clear cytoplasm, separated by septa of fibrous tissue and invading the connective tissue. Tumor cells were positive for p63 and AE1/AE3 and negative for PAX8, smooth muscle actin (AML) and estrogen receptor. The diagnosis was carcinoma with a clear cell pattern, and it was not possible to distinguish between HCCC and CCOC. In this study, clinicopathologic, histologic, and immunohistochemistry features of CCOC and HCCC were discussed due to the challenging histological diagnosis. Radical surgical treatment and rehabilitation of the patient through graft and dental implants were performed. The patient is under follow-up with no signs of recurrence.

Clear-cell variant of oral squamous cell carcinoma: A rare entity

Clear-cell variant of oral squamous cell carcinoma is an extremely rare entity in the maxillofacial region. We report a case of 42-year-old female who presented with a soft-tissue growth with erythematous and nonscrapable irregular white patches on the left alveolar mucosa for the past 3 months. Histopathologic examination showed lobules and sheets of clear cells with features of malignancy extending from the surface epithelium. Periodic acid–Schiff and mucicarmine stains showed a negative reaction. Immunohistochemical study using antibody for pan-cytokeratin revealed intense positivity and negative for the markers such as S-100, smooth muscle actin and CD 117.

Clear cell variant squamous cell carcinoma of temporal bone: Case report and literature review

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Squamous cell carcinomas of the temporal bone are rare malignancies.

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This is a case of clear cell squamous cell carcinoma.

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Otalgia, otorrhea, and hearing loss are the usual presenting symptoms.

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This case of temporal bone SCC was aggressive in nature and presentation.

Introduction

Squamous cell carcinoma (SCC) of the temporal bone is a rare malignancy. Clear cell SCC is a rare variant of SCC of temporal bone in which no clear risk factor has been suggested as possible etiology. Otalgia, otorrhea, and hearing loss are the usual presenting symptoms of SCC of the temporal bone.

Presentation of case

This is a case is of a 62-year-old female who presented with a 6 months’ history of experiencing intermittent left hearing disturbance, loss of balance, persistent left tinnitus, left otalgia radiating to the lateral neck and post auricular swelling. Histology showed clear cell variant, well differentiated SCC. The patient’s tumor was found to be non-resectable due to the extensive invasion. The patient was referred for palliative therapy by medical and radiation oncology, however, the patient couldn't tolerate it. One month later she passed away.

Discussion

SCC of the temporal bone is a challenging clinical entity. It is diagnosed mainly by clinical and radiological assessment, and deep biopsies are used to confirm the diagnosis. Temporal bone SCC is usually diagnosed late due to delayed presentation. This case of temporal bone SCC was aggressive in nature and presentation. The presentation was different from the known triad of symptoms of temporal bone SCC which is offensive otorrhea, pain, and bleeding.

Conclusion

This case showed a very destructive and bizarre clinical presentation but more report of cases is needed to have a better characterization of the clinical presentation and prognosis of this variant of SCC of temporal bone.