Cellular myxoma is an uncommon type of myxoid benign tumor, predominantly occurring in adult female patients aged >40 years. This report aims to document a case of cellular myxoma that occurred in the buccal mucosa. Compared to intramuscular myxomas, cellular myxoma demonstrates hypercellularity and vascularity. Its manifestation in the soft tissue of the head and neck area is exceptionally rare. Generally, cellular myxoma manifests as a firm and immovable mass covered with normal oral mucosa, with no associated clinical symptoms. Homogenous low signal intensity on T1-weighted scans and high-signal intensity on T2-weighted magnetic resonance scans reveal cellular myxoma, as most lesions show well-defined margins and heterogeneous contrast enhancement. The significant histologic features include a focal or diffuse increase in cellularity with fibroblast-like cells and vascularity with an abundant collagenous matrix. Our presented case reflects these facts examinations, based on which a final diagnosis of cellular myxoma was made. Immunohistochemistry revealed locally and diffusely positive SMA and CD34. The clinical tendency of cellular myxoma with hypercellularity may affect the production of myxoid and collagenous substrates, and if complete resection is not performed, the possibility of local recurrence in the primarily affected region remains. Hence, complete surgical excision was performed under general anesthesia, and follow-up until a year after treatment revealed no observed recurrence. To achieve precise diagnosis and complete treatment without local recurrence, several diagnostic examinations should be considered.

Oral adenosquamous carcinoma (ASC) is a rare and aggressive type of squamous cell carcinoma (SCC). It is characterized by a squamous component originating at the mucosa and a deep glandular component. ASC may be misdiagnosed as SCC by superficial incisional biopsy including only the squamous component. ASC has a worse prognosis than general variants of SCC, so accurate diagnosis is essential for patient survival. We present a case report of a large ASC arising in the buccal mucosa, first mistaken as general SCC.

Caliber persistent artery (CPA) is a vascular anomaly presenting as a bluish and pulsatile artery in the subepithelial tissue. Although the incidence of CPA was debated, many CPAs occurred in the perioral and facial tissues at which the embryonal strapedial artery networks were distributed. The present study demonstrated a case of CPA occurred in the retromolar buccal mucosa in a 37 years old male. The lesion showed many pinkish granular spots, but was asymptomatic except biting irritation during mastication. It had slowly increased in size up to 20 × 25 mm for 3 years, and recently became hemorrhagic due to the biting injury between left upper and lower second molars. With the fear of oral cancer an incisional biopsy was performed, and followed by histological and immunohistochemical study. Histologically the lesion showed many tortuous artery localized at the submucosa area, and the arterial wall was thick and its lumen was narrowed and shrunken. In the immunochemistry α-SMA was positive for thick smooth muscle layer of artery and arterioles, TGase 2 was weakly positive for the luminal surface of arterial intima, and bFGF was consistently positive for the perivascular fibrous tissue. But PCNA, VEGF, CD31, CMG2, TGF-β1, HSP-70, and 14-3-3 were almost negative for the vascular tissue. Therefore, it was presumed that the lesion was not actively proliferative nor degenerative but still retained its cellular stability and slow growing potential. It was finally diagnosed as CPA differentially from arterio-venous malformation, hemangioma, lymphangioma, and squamous cell carcinoma. The retromolar buccal mucosa CPA is first reported in this study and may present usual clinical findings depending on its size and location. This asymptomatic lesion could be severely hemorrhagic by minor biting injury, therefore, precise differential diagnosis should be made through biopsy, and careful therapy be followed.

Oral galvanism is known to induce chronic irritation on oral mucosa, but the related pathology rarely occurs. A 65 years old male complained of linear horizontal ulcerations on his bilateral buccal mucosa for one month. The oral ulcerations were parallel and approximated to his occlusal plane. He had multiple metallic crowns using gold and nickel cobalt alloy at bilateral upper and lower molar teeth, and also had accustomed to heavy smoking for more than twenty years. Biopsy examination was performed with immunohistochemical staining using antisera of PCNA, D2-40, and PARP. The epithelial ulcer had clear margin and was replaced by granulation tissue containing many dilated lymphatic vessels, which were positive for D2-40, but showed no feature of pseudo-necrotic membrane. Nearby epithelium showed the typical features of leukoedema, characterized by edematous keratinocytes with clear cytoplasms and pyknotic nuclei, low rete ridges, and rough superficial epithelial layer, where PCNA was rarely positive. Some superficial edematous keratinocytes showed perinuclear cytoplasmic vacuolization, and their peripheral nuclear chromatins were positive for PARP. Taken together, the present mucosa ulceration was different from aphthous stomatitis, herpes stomititis, oral lichen planus, etc., thus it was postulated that the galvanic current generated from between the upper and lower dissimilar metal crowns could affect the precedent leukoedema caused by heavy smoking habit and produce the linear horizontal buccal ulceration. Therefore, the present case was diagnosed as galvanic mucositis associated with leukoedema, and it was also hypothesized that the mild and persistent galvanic current was able to deplete the cytoplasmic fluid of leukoedema keratinocytes via the osmotic pressure difference elicited by increased ionic concentration of galvanism, and followed by severe keratinocyte apoptosis and oral mucosa ulceration.

Dermoid and epidermoid cysts in the oral cavity are uncommon and account for less than 0.01% of all oral cysts. The large majority of cases arise in the floor of the mouth and there are rare in other sites. We would like to report an unusual case of epidermoid cyst at the buccal mucosa in a 66-year-old male with a review of literature.