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

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.

Metastatic Sarcomatoid Renal Cell Carcinoma: A Journey From the Kidney to the Gingiva

Oral metastatic lesions are very rare and are often diagnosed at a later stage, complicating treatment. Renal cell carcinoma (RCC) is the third most frequent neoplasm to metastasize to the oral cavity, following breast and lung cancers. These metastatic lesions are usually asynchronous and develop after the initial diagnosis, affecting the overall survival rate. This report describes a known case of RCC with a growth in the mandibular gingiva. Multiple pulmonary and femoral metastases appeared five years after the initial renal lesion. The gingival growth was excised and referred for histopathological examination, which revealed a pleomorphic sarcomatoid cellular morphology. Immunohistochemistry with an array of markers led to the diagnosis of sarcomatoid RCC, a rare high-grade tumor. This case underscores the importance of detailed history-taking, interpretation of clinical findings, and emphasis on histopathological examination to arrive at a conclusive diagnosis.

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.