Extranodal nasal NK/T-cell lymphoma: a rare oral presentation and FASN, CD44 and GLUT-1 expression.

Extranodal natural killer (NK)/T-cell lymphoma is an aggressive malignant tumor with distinctive clinicopathological features, characterized by vascular invasion and destruction, prominent necrosis, cytotoxic lymphocyte phenotype and a strong association with Epstein-Barr virus. Here is reported an extranodal nasal NK/T-cell lymphoma case, involving the maxillary sinus, floor of the orbit, and interestingly extending to the oral cavity through the alveolar bone and buccal mucosa, preserving the palate, leading to a primary misdiagnosis of aggressive periodontal disease. Moreover, this work investigated for the first time the immunohistochemical expression of fatty acid synthase (FASN) and glucose transporter 1 (GLUT-1) proteins in this neoplasia. FASN showed strong cytoplasmatic expression in the neoplastic cells, whereas GLUT-1 and CD44 were negative. These findings suggest that the expression of FASN and the loss of CD44 might be involved in the pathogenesis of the extranodal nasal NK/T-cell lymphoma, and that GLUT-1 may not participate in the survival adaptation of the tumor cells to the hypoxic environment. Further studies with larger series are required to confirm these initial results.

Extranodal Nasal NK/T-Cell Lymphoma: A Rare Oral Presentation and FASN, CD44 and GLUT-1 Expression

Extranodal natural killer (NK)/T-cell lymphoma is an aggressive malignant tumor with distinctive clinicopathological features, characterized by vascular invasion and destruction, prominent necrosis, cytotoxic lymphocyte phenotype and a strong association with Epstein-Barr virus. Here is reported an extranodal nasal NK/T-cell lymphoma case, involving the maxillary sinus, floor of the orbit, and interestingly extending to the oral cavity through the alveolar bone and buccal mucosa, preserving the palate, leading to a primary misdiagnosis of aggressive periodontal disease. Moreover, this work investigated for the first time the immunohistochemical expression of fatty acid synthase (FASN) and glucose transporter 1 (GLUT-1) proteins in this neoplasia. FASN showed strong cytoplasmatic expression in the neoplastic cells, whereas GLUT-1 and CD44 were negative. These findings suggest that the expression of FASN and the loss of CD44 might be involved in the pathogenesis of the extranodal nasal NK/T-cell lymphoma, and that GLUT-1 may not participate in the survival adaptation of the tumor cells to the hypoxic environment. Further studies with larger series are required to confirm these initial results.

O linfoma de células natural killers (NK)/T extranodal é um tumor maligno agressivo com características clinicopatológicas distintas, caracterizadas por invasão e destruição vasculares, necrose proeminente, fenótipo linfocítico citotóxico e uma forte associação com o vírus Epstein-Barr. Relatamos aqui um caso de linfoma de células NK/T nasal extranodal, envolvendo o seio maxilar, assoalho de órbita, e interessantemente estendendo-se para a cavidade oral através do osso alveolar e mucosa vestibular, preservando o palato, levando a um diagnóstico inicial equivocado de doença periodontal agressiva. Ainda, nós investigamos pela primeira vez a expressão imunoistoquímica das proteínas Fatty acid sinthase (FASN) e glucose transporter 1 (GLUT-1) nesta neoplasia. FASN revelou uma forte expressão citoplasmática nas células neoplásicas, enquanto GLUT-1 e CD44 foram negativas. Estes achados sugerem que a expressão de FASN e a perda de CD44 podem estar envolvidas na patogênese do linfoma de células NK/T nasal extranodal, e que GLUT-1 não deve participar da adaptação das células tumorais ao ambiente de hipóxia. Estudos adicionais com séries maiores são necessários para confirmar nossos resultados iniciais.

Ectomesenchymal chondromyxoid tumor: histopathologic and immunohistochemical study of two cases without a chondroid component.

Ectomesenchymal chondromyxoid tumor (ECT) is a rare benign neoplasm usually affecting the anterior dorsum of the tongue. Histopathologically, it is formed by spindle, round and/or polygonal cells embedded in a chondromyxoid matrix. Immunohistochemical positivity for vimentin, S-100 protein, glial fibrillary acid protein and neuron-specific enolase are helpful to confirm the diagnosis. There are 42 cases of ECT of the tongue reported in the English language literature, three of them showing no chondroid matrix. We describe two additional cases of ECT lacking the chondroid component, exhibiting areas of reticulated myxoid and cellular pattern. Considering the microscopical features, ECT can be classified in classic and 'chondroid-free' variants, the latter including the reticulated myxoid and cellular patterns. It is important to consider that the cellular ECT usually exhibits predominance of an infiltrative atypical cellular component that may mimic a malignant tumor.

Crystal-storing histiocytosis: a rare lesion in periapical pathology.

Crystal-storing histiocytosis is a rare manifestation of plasma cell dyscrasia/monoclonal gammopathies and lymphoproliferative disorders, characterized by cytoplasmic accumulation of crystallized immunoglobulins in histiocytes. Nevertheless, some reported cases of crystal-storing histiocytosis raise the possibility that this lesion may also be reactive. Crystal-storing histiocytosis in the oral cavity is extremely rare; only one case affecting the tongue has been reported in the English-language literature. In this report, we discuss the case of a 38-year-old man who presented a persistent periapical lesion affecting the maxillary left lateral incisor. Histopathological analysis showed numerous crystal-laden histiocytes associated with a mild plasma cell infiltrate within a fibrous stroma. The plasma cells failed to show clonal light-chain restriction, and the patient had no associated hematologic disorder or systemic disease. Thus, this lesion was probably the result of hypersecretion of immunoglobulins by polyclonal plasma cells found in the periapical lesion. Crystal-storing histiocytosis should be considered in the differential diagnosis of periapical lesions.

Immunohistochemical evaluation of angiogenesis and tryptase-positive mast cell infiltration in periapical lesions.

INTRODUCTION: Several studies have linked mast cells (MCs) with angiogenesis. The aim of this study was to correlate angiogenesis with MCs in radicular cyst (RC) and periapical granuloma (PG) cases. METHODS: Forty-eight samples of periapical lesions, diagnosed as RC (n = 24) and PG (n = 24), were included. The microvessel density and microvessel area measured through the immunoexpression of CD105 and CD34 and the MC density measured through the immunoexpression of tryptase were performed. RESULTS: MCs were detected in all RCs and PGs (P = .888), mainly in perivascular location and within fibrous stroma. CD34 stained all vessels present in all RC and PG cases. CD105 revealed differential expression, stained preferentially vessels of greater lumen, and showed variable location inside fibrous stroma in both lesions. There was a significant difference of microvessel density determinate by CD34 and CD105 in RCs (r = 0.634, P = .002) and in PGs (r = 0.5709, P = .0036). The difference was also observed when comparing age of the patient in both lesions. Considering the microscopic association between highest concentration of MCs and vascularization, CD105-positive vessels in 50% of RCs and 70.8% of PGs and CD34-positive vessels in 66.7% of RCs and 87.5% of PGs showed areas of close association with MCs. CONCLUSIONS: These results suggest differential expression of CD105 within RC and PG. There is no difference in angiogenesis and MC density between RC and PG. Moreover, because of the association between MCs with vessels and fibrous stroma, other possible roles of tryptase, in addition to the angiogenic properties, should also be considered.

Oral metastasis of alveolar soft-part sarcoma: a case report and review of literature.

Alveolar soft-part sarcoma (ASPS) is a rare malignant neoplasm with uncertain histogenesis and with a distinctive morphology. It has been described in the oral cavity, but this is the first report of ASPS metastasizing to the maxillary tuber region. A 27-year-old male patient, who was under chemotherapy treatment for ASPS of the thigh, presented in our dental clinic with a painless and pedunculated nodule on the right tuber maxillae. The nodule was erythematous with smooth and lobular surface, measuring 3 cm in maximum diameter. An incisional biopsy was performed and the diagnosis of metastatic ASPS was made. Histologically, the tumor was characterized by a proliferation of polyhedral cells in pseudoalveolar pattern. Tumor cells were large, showing granular cytoplasm, periodic acid-Schiff positive diastase-resistant intracytoplasmic material, and vesicular nuclei with prominent nucleoli. Unfortunately, the patient died 2 months after the diagnosis of the oral metastasis. Metastases of ASPS to the mouth are very rare and indicate a poor prognosis.