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Atypical lipomatous tumor (ALT), one of the histologic subtypes of liposarcoma, is locally aggressive with intermediate malignant potential and is categorized as a synonymous entity with well-differentiated liposarcoma (ALT/WDLPS). Although ALT/WDLPS is the most common subtype of liposarcoma in the oral and maxillofacial region, its occurrence is extremely rare, and asymptomatic clinical behavior often delays definitive diagnosis and treatment. We present an extremely rare case of ALT/WDLPS in the buccal mucosa of an elderly Japanese woman. A provisional diagnosis of benign tumor was made from clinical symptoms that involved findings on magnetic resonance imaging. Microscopic examination revealed mature adipocytes with substantial variation in cell size, fewer multivacuolated lipoblasts, and positive stain with MDM-2 and P16, which resulted in a definitive diagnosis of ALT/WDLPS. Conservative surgical resection resulted in locoregional recurrence; however, no evidence of dedifferentiation was detected, and repeat conservative resection finally allowed the patient to avoid esthetic and functional disorder and to obtain an uneventful clinical prognosis over the long-term follow-up period. We also review previous reports of cases of ALT/WDLPS arising from the cheek/buccal mucosa.

A case of an intramasseter vascular malformation excised by the high perimandibular approach (alternatively called high submandibular transmasseteric approach) is presented. A 46-year-old Japanese woman complained of swelling of the right buccal region. Computed tomography (CT) of the right intramasseter region showed a radiolucent area of about 2 cm that included a rounded radiopaque lesion at the masseter muscle. Magnetic resonance imaging (MRI) showed hyperintensity on short T1 inversion recovery (STIR) images and T2-weighted images in the right masseter muscle lesion with the rounded hypointensity signal areas. A vascular malformation of the right masseter muscle was diagnosed, and, considering the size and location of the tumor, surgery was scheduled and performed by the high perimandibular approach. After placing the skin incision below the edge of the angle of the mandible, the skin and subcutaneous tissue were dissected and undermined upward over the platysma muscle. Then, the platysma muscle was incised, followed by exposure of the masseter muscle. After exposing the tumor lesion, tumor dissection with muscle tissue was performed under clear, direct visualization. The final diagnosis was an intramasseter venous malformation. There were no postoperative complications such as facial palsy or trismus. The patient was satisfied with the aesthetic outcome, and recurrence has not been seen 12 months after treatment. Considering the size and location of the tumor, the high perimandibular approach is an effective and useful alternative for intramasseter muscle tumors.

Objective Treatment of mandibular lesions sometimes leads to the formation of large defects in the bone. Mandible reconstruction using grafted tissue, bone, and/or medical implants is required following the resection of such lesions. However, such grafts may not completely restore the continuity of the mandible. Facial transplantations using allografts are common, but mandibular allotransplantation has not been performed in humans, due to the unstable immune reaction of the complex tissue. In this study, mandibular transplantations performed under the effect of the immunosuppressive agent, FK506, were evaluated in dogs. Methods Mandibular allotransplantations were performed in 21 pairs of sex-blind beagle dogs. The left side of the mandible in the donor dog was transplanted to the left side of the mandible in the recipient dog. The FK506 doses were 0 mg for 3 dog pairs, 0.08 mg/kg/day for 3, 0.12 mg/kg/day for 5, 0.16 mg/kg/day for 5, and 0.32 mg/kg/day for 5 pairs. Twelve weeks after transplantation, the dogs were euthanized. Computed tomography (CT) and histological examinations of the transplanted sides were performed. Results Successful graft acceptance was dependent on immunosuppressive agent doses, and dogs administered more than 0.16 mg/kg/day FK506 showed 100 % survival. However, dogs administered 0.32 mg/kg/day FK506 showed significant weight loss 12 weeks after the surgery. CT findings showed thick mandibular cortical bone in the transplanted sites. Conclusions These results indicate that 0.16 mg/kg/day FK506 was the ideal dose for allotransplantations. Bone hyperplasia was observed in the transplanted sides, but it is not a disadvantage for allotransplantations.

A 60-year-old woman presented with a painless swelling in the right preauricular region. Physical examination revealed a soft, nontender, oval-shaped lump in this location. Computed tomography indicated an anterolateral cystic lesion that was attached to the condyle of the mandible and to the accessory parotid gland. Differential diagnoses included ganglion cyst, synovial cyst of the temporomandibular joint, and accessory parotid gland cyst. Surgical removal of the cyst was performed with the patient under general anesthesia. The specimen was 18 × 20 × 18 mm in size; it contained fluid that was clear, slightly yellow, and amylase positive. Hematoxylin and eosin staining revealed that a bilayer cuboidal epithelium lined the cyst wall. Immunohistochemical analyses of the cyst wall showed strong expression of cytokeratin and weak expression of vimentin. The final diagnosis was a salivary duct cyst. The postoperative course was uneventful except for a transient facial motor paresis.

Lymph node (LN) metastasis has been suggested as a major prognostic factor for oral cancer. Knockdown of the growth factors and receptors involved in these metastatic mechanisms could significantly reduce LN metastasis and improve the survival of oral cancer patients after treatment. The present study, therefore, aimed to evaluate the expression levels of the following growth factors and receptors in squamous cell carcinoma (SCC) of the tongue: the vascular endothelial growth factor (VEGF)‑C and VEGF‑D, which bind to the cell surface tyrosine kinase receptor VEGF receptor‑3 (VEGFR‑3); C‑C motif chemokine receptor 7 (CCR7); neuropilin (NRP)1 and NRP2; and semaphorin 3E (SEMA3E). Furthermore, we assessed microvessel density (MVD) and lymphatic vessel density (LVD) to demonstrate the correlation between these factors and regional LN metastasis, with respect to the clinicopathological features. Finally, we analyzed the correlation between these proteins and overall or disease‑free survival, in order to demonstrate their prognostic value. Univariate analysis revealed a significant association between LN metastasis and the expression levels of VEGF‑C, VEGFR‑3, CCR7, NRP1, and SEMA3E, as well as LVD, in SCC cells. In contrast, multivariate analysis identified associations between LN metastasis and NRP1 expression, as well as between LN metastasis and LVD; however, no correlation was found between LN metastasis and the expression levels of the other proteins. The expression levels of VEGF‑C, VEGFR‑3, NRP1, and SEMA3E, as well as LVD, were correlated with disease‑free survival time. These results indicate that LN metastasis is associated with poor survival in SCC. This study suggests that NRP1 expression and LVD are independent factors that are likely to predict the risk of LN metastasis in SCC of the tongue, whereas the expression of VEGF‑C, VEGFR‑3, CCR7, and SEMA3E are non‑independent predictive factors.