The clinicopathological and prognostic significance of autonomic nerves in salivary duct carcinoma.

Many researchers have focused on the role of the autonomic nervous system in the tumor microenvironment. Autonomic nerves include the sympathetic and parasympathetic nerves, which are known to induce cancer growth and metastasis. However, in salivary duct carcinoma (SDC), a rare and highly malignant tumor, the issue should be investigated from both biological and therapeutic perspectives. We explored the clinicopathological and prognostic implications of the autonomic nerves in 129 SDCs. Immunohistochemistry was performed to determine the nature of each nerve using antibodies against S100, tyrosine hydroxylase (TH) as a sympathetic marker, and vesicular acetylcholine transporter (VAChT) as a parasympathetic marker. The area of each marker-positive nerve was digitized and evaluated quantitatively. Double immunofluorescence for TH and VAChT was performed in selected cases. The expression of the secreted neurotrophins was also examined. S100-positive nerves were present in the cancer tissue in 94 of 129 cases (72.9%). Among them, TH-positive sympathetic nerves and/or VAChT-positive parasympathetic nerves were identified in 92 cases (97.9%), and 59 cases (62.8%) had TH/VAChT-co-expressing nerves. Double immunofluorescence revealed a mosaic pattern of sympathetic and parasympathetic fibers in co-expressing nerve bundles. The presence of autonomic nerves, regardless of their area, was significantly associated with aggressive histological features, advanced T/N classification, and a poor prognosis, with shorter disease-free and overall survival. There was an association between some tumor immune microenvironment-related markers and the autonomic nerve status, but not the latter and the secreted neurotrophin expression. This study suggests that autonomic nerves might play a role in the progression of SDC.

A giant peripheral ossifying fibroma of the maxilla with extreme difficulty in clinical differentiation from malignancy: a case report and review of the literature.

BACKGROUND: Peripheral ossifying fibroma is a nonneoplastic inflammatory hyperplasia that originates in the periodontal ligament or periosteum in response to chronic mechanical irritation. Peripheral ossifying fibroma develops more commonly in young females as a solitary, slow-growing, exophytic nodular mass of the gingiva, no more than 2 cm in diameter. While various synonyms have been used to refer to peripheral ossifying fibroma, very similar names have also been applied to neoplastic diseases that are pathologically distinct from peripheral ossifying fibroma, causing considerable nomenclatural confusion. Herein, we report our experience with an unusual giant peripheral ossifying fibroma with a differential diagnostic challenge in distinguishing it from a malignancy. CASE PRESENTATION: A 68-year-old Japanese male was referred to our department with a suspected gingival malignancy presenting with an elastic hard, pedunculated, exophytic mass 60 mm in diameter in the right maxillary gingiva. In addition to computed tomography showing extensive bone destruction in the right maxillary alveolus, positron emission tomography with computed tomography revealed fluorodeoxyglucose hyperaccumulation in the gingival lesion. Although these clinical findings were highly suggestive of malignancy, repeated preoperative biopsies showed no evidence of malignancy. Since even intraoperative frozen histological examination revealed no malignancy, surgical resection was performed in the form of partial maxillectomy for benign disease, followed by thorough curettage of the surrounding granulation tissue and alveolar bone. Histologically, the excised mass consisted primarily of a fibrous component with sparse proliferation of atypical fibroblast-like cells, partly comprising ossification, leading to a final diagnosis of peripheral ossifying fibroma. No relapse was observed at the 10-month follow-up. CONCLUSIONS: The clinical presentation of giant peripheral ossifying fibromas can make the differential diagnosis from malignancy difficult. Proper diagnosis relies on recognition of the characteristic histopathology and identification of the underlying chronic mechanical stimuli, while successful treatment mandates complete excision of the lesion and optimization of oral hygiene. Complicated terminological issues associated with peripheral ossifying fibroma require appropriate interpretation and sufficient awareness of the disease names to avoid diagnostic confusion and provide optimal management.

Brain metastases in patients with salivary duct carcinoma: A retrospective study.

BACKGROUND: Salivary duct carcinoma (SDC) is a high-grade adenocarcinoma with a 5-year survival rate of 40%. Although drug therapy has improved patients' prognosis, the impact of brain metastasis (BM) remains poorly understood. We aimed to retrospectively examine the incidence of BM in patients with SDC (n = 464) and develop a tool to estimate their prognoses. METHODS: We retrospectively examined 464 patients with SDC enrolled in a multicenter study. We investigated the incidence of BM, overall survival (OS) rates, and factors affecting prognosis in patients with BM. We also developed an SDC-graded prognostic assessment (GPA) score for disease prognostication. RESULTS: Sixty-five (14%) patients had BM. The median OS (mOS) was 13.1 months. On univariate and multivariate analyses, factors such as Eastern Cooperative Oncology Group Performance Status >1, human epidermal growth factor receptor 2-negative status, and locoregional uncontrolled disease were associated with poor OS. SDC-GPA scores according to the prognostic factors were 0, 1, 2, and 3 points, and mOS estimates were 50.5, 16.1, 3.9, and 1.2 months, respectively (p < 0.001). CONCLUSION: The SDC-GPA score emerged as a useful prognostication tool for patients with BM.