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Rhabdomyosarcoma (RMS) is a soft tissue sarcoma that develops from skeletal striated muscle cells. RMSs are exceedingly rare in the oral cavity, particularly in the gingiva. Herein, we reported the clinicopathological and immunohistochemical features of a rare case of RMS in a 30-year-old female presenting clinically as a painful polypoid nodule on the mandibular gingiva. Microscopically, the tumor showed atypical spindle cells with elongated nuclei and eosinophilic cytoplasm arranged in a fascicular pattern. In focal areas, the tumor cells exhibited rhabdomyoblastic differentiation. Immunohistochemistry showed strong positivity for desmin, myogenin (scattered cells), and MyoD1. The patient underwent surgical resection followed by postoperative complementary radio- and chemotherapy. However, the patient had a local recurrence seven months after the initial treatment. She was submitted to a total mandibulectomy associated with adjuvant radiotherapy. However, she died two months after reoperation due to complications secondary to radiation therapy. Because of the rarity in the oral cavity and non-specific signs and symptoms, the clinical diagnosis of RMS is difficult and often overlooked. Therefore, careful histopathological and immunohistochemistry analysis of these tumors is essential to correct diagnosis. Early surgical excision with tumor-free margins and prolonged follow-up are strongly recommended.

Metastases in the oral cavity are rare and frequently associated with widespread disease and poor prognosis. Clear cell renal cell carcinoma (ccRCC) is the most common subtype of renal cell carcinoma (RCC), known for its propensity for metastatic spread. The diagnosis of oral metastases from ccRCC is challenging, especially when the patient has no history of primary neoplasm. Herein, we reported a rare metastatic ccRCC in a 58-year-old female presenting clinically as a painless nodule on the tongue mimicking a benign lesion. Microscopically, the tumor showed a proliferation of clear cells organized in nests with a predominantly lobular arrangement. The dense connective tissue stroma was highly vascularized, exhibiting some areas with a hyalinized aspect. Immunohistochemistry showed focal positivity for pan-cytokeratin AE1/AE3 and strong positivity for CK8, CK18, epithelial membrane antigen (EMA), vimentin, and CD10. S-100 protein, HMB-45, CK7, and CK20 were negative. The definitive diagnosis was metastatic ccRCC. The treatment was initiated with sunitinib. However, the disease progressed, and the patient was submitted to palliative care. Despite the low survival rate of patients with metastases, the clinician's experience in identifying an oral metastatic lesion may reveal undiagnosed primary tumors and provide better prognosis and survival rates.

Myoepithelial carcinomas of the head and neck are often located in the major salivary glands, notably in the parotid glands, being less frequent in the minor salivary glands. Noteworthy, myoepithelial carcinoma in the maxillary sinus is extremely rare. In fact, only five cases have been previously published to date. Here, we present, for the first time, a detailed immunohistochemical and in situ hybridization analysis of a SMARCB1 (INI-1)-intact myoepithelial carcinoma with rhabdoid features, expanding the histopathological spectrum of high-grade sinonasal carcinomas.

To identify chromosome deletions in 1q25, 1p36 and 1pTEL, and chromosome 17 ploidy status in oral epithelial dysplasia (OED) and oral squamous cell carcinoma (OSCC).Samples from 57 OED and 63 OSCC were selected. FISH was performed using centromeric probes 17 and n LSIR 1p36/LSI 1q25 Dual Color Probe.In OED, deletions were found only in 1pTEL region (29.8%). In OSCC, there was a higher frequency of deletion in 1pTEL (79.4%), followed by 1p36 (73.0%), and 1q25 (20.6%). Advanced TNM clinical stages (III/IV) showed all the deletions studied; at early clinical stages (I/II) of OSCC, deletions were observed only in 1pTEL. The frequency of deletion in 1p36 was 17.0 times higher in OSCC at advanced clinical stages (PR: 17.00). The median number of cell nuclei with chromosome 17 aneuploidy was higher in OSCC than in OED (P 0.001). Early clinical stages of OSCC showed lower median number nuclei with aneuploidy when compared to advanced tumors (P 0.05). Tumors harboring deletions in 1p36, 1q25 and 1pTEL revealed higher median numbers of trisomic/polysomic nuclei when compared to lesions exhibiting no abnormalities in chromosome 1 (P 0.05).A higher prevalence of chromosomal abnormalities was found in OSCC than in OED, while in OSCC, higher abnormalities were present in lesions with higher TNM staging. 1pTEL deletion and monosomy of chromosome 17 are possible markers for progression of OED to OSCC. 1p36 deletion and trisomy/polysomy of chromosome 17 could be markers of worse prognosis of OSCC.