Follicular lymphoid hyperplasia of the posterior maxillary site presenting as uncommon entity: a case report and review of the literature.

BACKGROUND: Follicular lymphoid hyperplasia (FLH) is characterized by an increased number and size of lymphoid follicles. In some cases, the etiology of FLH is unclear. FLH in the oral and maxillofacial region is an uncommon benign entity which may resemble malignant lymphoma clinically and histologically. CASE PRESENTATION: We report the case of a 51-year-old woman who presented with an asymptomatic firm mass in the left posterior maxillary site. Computed tomography scan of her head and neck showed a clear circumscribed solid mass measuring 28 × 23 mm in size. There was no evidence of bone involvement. Incisional biopsy demonstrated benign lymphoid tissue. The patient underwent complete surgical resection. Histologically, the resected specimen showed scattered lymphoid follicles with germinal centers and predominant small lymphocytes in the interfollicular areas. Immunohistochemically, the lymphoid follicles were positive for CD20, CD79a, CD10, CD21, and Bcl6. The germinal centers were negative for Bcl2. Based on these findings, a diagnosis of benign FLH was made. There was no recurrence at 1 year postoperatively. CONCLUSIONS: We diagnosed an extremely rare case of FLH arising from an unusual site and whose onset of entity is unknown. Careful clinical and histopathological evaluations are essential in making a differential diagnosis from a neoplastic lymphoid proliferation with a nodular growth pattern.

Toll-like receptor 2 activation implicated in oral squamous cell carcinoma development.

Recent studies have revealed that Toll-like receptors (TLRs) are highly expressed and activated in many types of cancer. Physiologically, TLR2 recognizes bacteria and other microorganisms in the oral cavity; however, the role of TLR2 in oral squamous cell carcinoma (OSCC) is unclear. In this study, we demonstrated that TLR2 is highly expressed in OSCC in comparison with adjacent non-malignant tissue. TLR2 was also expressed in OSCC-derived cell lines, and its expression was activated by ligands derived from bacteria and mycoplasma. Furthermore, to elucidate the mechanism of OSCC progression via TLR2 signal transduction, we focused on microRNAs (miRNAs) that are induced by TLR2 activation. Interestingly, ligand activation of TLR2 induced the expression of miR-146a and we found that downregulation of caspase recruitment domain-containing protein 10 (CARD10) mRNA in OSCC-derived cell lines. Moreover, knockdown of CARD10 induced resistance to cisplatin-induced apoptosis in OSCC cells. These findings suggest that the activation of TLR2 by bacterial components can enhance the progression of OSCC and may be implicated in acquired resistance to cisplatin-induced apoptosis through regulation of the miR-146a pathway.

Intraepithelial CD8+ lymphocytes as a predictive diagnostic biomarker for the remission of oral lichen planus.

Oral lichen planus (OLP) is an autoimmune inflammatory disease of the oral mucosa whose etiology remains unknown. Moreover, the possibility of OLP being a premalignant change is under debate. Various types of immune cells infiltrate the OLP lesion and affect its clinicopathological features. However, the diversity of infiltrating immune cells has not been fully clarified in relation to OLP diagnosis. In this study, we quantitatively examined CD8+ lymphocyte infiltration by immunohistochemistry, which is the principal effector of cytotoxic immune reaction in 123 cases of OLP specimens. Our examination revealed that high-grade intraepithelial CD8+ lymphocyte infiltration was associated with a high remission rate. Evaluation of the infiltration of T-bet+ and FoxP3+ lymphocytes, which corresponded to the Th1 and Treg CD4+ subsets, respectively, showed that intraepithelial CD8+ lymphocytes were associated with the remission rate in the subgroup with a higher T-bet/FoxP3 subset balance that is inducible for cytotoxic immunity. We also investigated the cutoff value of CD8+ lymphocyte infiltration for histopathological diagnosis. By microscopic counting, 16 cells/high-power field, which was also confirmed in the validation cohort, was established as the cutoff value for intraepithelial CD8+ lymphocyte infiltration for predicting the remission of OLP. Remitting OLP might be different from refractory OLP in terms of etiology and clinical behavior. Thus, intraepithelial CD8+ lymphocytes may serve not only as a predictive biomarker for remission but also as an area for further biomedical research regarding the etiology and premalignant potential of OLP.

Adenosquamous carcinoma of the tongue: clinicopathologic study and review of the literature.

Adenosquamous carcinoma (ASC) of the tongue is an uncommon malignant oral neoplasm with mixed glandular and squamous differentiation and a propensity for aggressive clinical behavior. Here, we report a rare case of ASC of the lateral border of the tongue in a 65-year-old Japanese man. The patient was treated by radical operation and remained well for 6 months before developing metastasis of the hilar and pretracheal lymph nodes. Subsequently, the patient was treated with combined chemotherapy (nedaplatin plus docetaxel and S-1 for two cycles, intravenously) and radiotherapy. Radiation therapy of metastatic lymph nodes was performed at a total dose of 60 Gy and was delivered in 2 Gy fractions 5 days/week. The patient is currently tumor free and is being followed up carefully. This article describes a rare case of ASC of the tongue and its conventional histologic, immunohistochemical, and electron microscopic findings, together with a review of the literature. The findings provide important information to better understand the possible clinical and therapeutic approaches for this uncommon tumor of the tongue.

Solitary myofibroma of the mandible: an immunohistochemical and ultrastructural study with a review of the literature.

A solitary myofibroma (MF) is an unusual spindle cell neoplasm that usually arises in the soft tissue, skin, or bone of the head and neck region in infancy. We report an extremely rare case of MF of the mandible in an 18-year-old Japanese woman together with the conventional histologic, immunohistochemical, and electron microscopic findings. The tumor was well circumscribed and composed of fibroblast-like or myofibroblast-like spindle cells. On immunohistochemical evaluation the tumor cells were positive for vimentin, α-smooth muscle actin, HHF-35, and calponin, but negative for neurogenic antigens and markers for vascular endothelial cells. The Ki-67 labeling index was 10 % and the p53 labeling index was 10 %. Ultrastructural examination revealed smooth muscle cell differentiation. The patient was treated by surgical resection and underwent follow-up without any signs of recurrence. MF presents a wide range of differential diagnosis, including benign and malignant neoplasms. Therefore, accurate diagnosis may avoid an unnecessarily aggressive therapy.

Exceptionally large solitary fibrous tumor arising from the cheek: an immunohistochemical and ultrastructural study with a review of the literature.

Solitary fibrous tumor (SFT) is a rare mass-forming soft tissue tumor that occurs most commonly in the pleura, but has been described in various extrathoracic sites. Extrapleural manifestation of SFT, particularly in the head and neck region, is rare. The most common extrapleural site is the oral cavity; these tumors have also been described in the orbit, nasopharynx, paranasal sinuses, salivary glands, and larynx. We report an extremely rare case of a SFT in the subcutaneous region of the cheek. This tumor in the left cheek was a large firm mass, approximately 8.5 cm × 6 cm in size and was successfully treated by surgical resection. Immunohistochemistry revealed reactivity for vimentin, CD34, and bcl-2, but no staining for cytokeratin, epithelial membrane antigen, S-100, desmin, caldesmon, actin, α-smooth muscle actin, CD117, and CD99. Immunohistochemical study is the key to establish a definitive diagnosis of SFT, and ultrastructural study is also useful for making an accurate diagnosis. The patient recovered uneventfully without evidence of tumor recurrence 2 years after surgery.