Oral focal mucinosis: A multi-institutional study and literature review.

BACKGROUND: Oral focal mucinosis (OFM) is a rare benign condition of unknown etiology, considered the oral counterpart of cutaneous focal mucinosis. We report the clinicopathologic features of 21 cases of OFM in conjunction with a review of the literature. METHODS: Clinical data were collected from the records of five oral and maxillofacial pathology services. All cases were evaluated by hematoxylin and eosin staining, histochemistry, and immunohistochemistry (vimentin, S-100, α-SMA, CD34, and mast cell). RESULTS: The series comprised 14 females (66.7%) and seven males (33.3%), with a mean age of 48.2 ± 20.7 years (range: 8-77 years) and a 2:1 female-to-male ratio. Most of the lesions affected the gingiva (n = 6, 28.6%) and presented clinically as asymptomatic sessile or pedunculated nodules with fibrous or hyperplasic appearance. All cases were negative for S-100 protein, CD34, and α-SMA and positive for Alcian blue staining. Conservative surgical excision was the treatment in all cases, and there was only one recurrence. CONCLUSION: OFM is a rare benign disorder that is often clinically misdiagnosed as reactive lesions or benign proliferative processes. Dermatologists and pathologists should consider OFM in the differential diagnosis of soft tissue lesions in the oral cavity, mainly located in the gingiva.

A rare case of oral squamous cell carcinoma in a patient with Cowden syndrome: Association or coincidence?

Cowden Syndrome (CS) is a rare genetic disease caused by mutations in the PTEN tumor suppressor gene, often presenting a challenging diagnosis due to its diverse clinical manifestations. Although extensively linked to several types of cancer, the precise association between CS and oral malignancies, particularly squamous cell carcinoma (SCC), remains poorly understood. This report describes a unique case of late diagnosis of CS in a 53-year-old female patient who later developed SCC in the inferior alveolar ridge, even without exposure to classic risk factors. The need to increase awareness in the medical and dental communities about CS and its manifestations in the oral cavity is highlighted. Early recognition and management of conditions associated with CS have a significant impact on patients' quality of life. Encouraging the publication of similar cases is recommended to encourage detailed analyzes and investigations in order to better understand the possible association between the syndrome and the development of malignancies in the oral cavity.

Intraosseous rhabdomyosarcoma of the maxilla with TFCP2 fusion: A rare aggressive subtype with predilection for the gnathic bones.

Rhabdomyosarcomas (RMS) are malignant tumors with skeletal muscle differentiation extremely rare in intraosseous sites. We reported a rare case of an aggressive intraosseous RMS found in the maxilla of a 17-year-old female patient with five months of evolution. Computed tomography revealed a large osteolytic lesion extending from tooth 21 to 27, causing buccal and lingual cortical plate perforation. Microscopically, the lesion showed a proliferation of spindle-shaped cells with elongated nuclei and eosinophilic cytoplasm, arranged in an interlaced fascicle pattern. The nuclei ranged from vesicular with distinct nucleoli to hyperchromatic. A focal component of plump to epithelioid cells with a moderate amount of eosinophilic cytoplasm was seen at the periphery of the tumor. The immunohistochemical analysis revealed positivity for desmin, MyoD1, and myogenin (scattered cells). S-100, SOX10, HMB45, ß-catenin, and CD34 were negative. Ki-67 was positive in 30% of tumor cells. Fluorescence in situ hybridization (FISH) analysis showed the presence of a FUS-TFCP2 fusion. The diagnosis was intraosseous RMS with TFCP2 fusion. Surgical excision followed by chemo- and radiotherapy was carried out; however, the patient died of disease nine months after the treatment. Because of the rarity and non-specific signs and symptoms, the clinical diagnosis of intraosseous RMS is difficult and often overlooked. Therefore, careful histopathological evaluation, supported by immunohistochemical and molecular analysis, is essential to correct diagnosis. Early surgical excision with tumor-free margins and prolonged follow-up are strongly recommended.

Regional Odontodysplasia Affecting the Maxilla.

Regional odontodysplasia (RO) is a rare dental anomaly of unknown etiology that can affect both deciduous and permanent dentition. RO is characterized by severe hypoplasia of enamel and dentin, and teeth affected are friable and more susceptible to caries and fractures. Most of the lesions occur in the anterior maxilla and correlation with clinical and radiographic features is essential to provide a correct diagnosis. The major criteria for diagnosis are predominantly based on radiography, which shows presence of large pulp chambers and a marked reduction in the radiopacity of enamel and dentin, making the distinction between these mineralized structures difficult. Early diagnosis is important to minimize future sequels and allow preventive or conservative treatment. The therapeutic approach of the RO should be based on the degree of severity of the anomaly and in the individual functional and aesthetic needs of each case. A classic case of RO affecting the maxilla is exemplified in this Sine Qua Non Radiology-Pathology article.