Bilateral submandibular gland oncocytoma in a patient with multiple endocrine neoplasia 2B syndrome and neurofibromatosis type 1: an unusual case

Submandibular Gland Oncocytoma: A Rare Tumor Case Series-Its Diagnosis and Treatment Based on Clinicopathology

Aim and Objective

Submandibular oncocytomas are rare benign salivary gland neoplasms, normally involves the parotid gland and few instances are stated in the submandibular gland region. As the clinical and histopathological features are overlapping to another salivary gland tumor like pleomorphic adenoma or warthin tumour, they are often misdiagnosed. They are typically found in patients aged 50-70 years with no gender preference. The aim of this paper is to assess the clinicopathological functions, diagnostic standards and treatment of submandibular gland oncocytomas via a series of three case reports.

Method and Results

We report a three case series of unilateral submandibular gland oncocytoma with female to male ratio 2:1, Size of tumor ranged from 1.8 to 10 cm, 2 cases have painless swelling and one involved tender mass. FNAC and CT scan confirmed the presence of an oncocytoma. The patient underwent unilateral submandibular gland resection and on follow up no evidence of any recurrence was identified.

Conclusion

Submandibular oncocytomas often present as solitary slow growing painless masses, which are firm on clinical examination. CT followed by fine-needle aspiration cytology (FNAC) would be the preferred diagnostic modalities. Due to its low rate of malignant transformation and recurrence, the best treatment is local resection with follow-up as necessary.

Oncocytoma of the Submandibular Gland: Diagnosis and Treatment Based on Clinicopathology

Background. Submandibular oncocytomas are rare benign salivary gland neoplasms. They are typically found in Caucasian patients aged 50-70 years with no gender preference. Due to the overlapping histological and clinical features of head and neck tumors, they are often misdiagnosed. Methods. We report a case of unilateral submandibular gland oncocytoma in a 63-year-old Caucasian man. Results. The patient underwent unilateral submandibular gland resection and histopathologic analysis of the tumor specimen. On follow-up at 2 weeks and 1 year, no recurrence was identified. Conclusion. Submandibular oncocytomas are best diagnosed with preoperative FNA and CT imaging and have distinctive findings on cytology and histology. CT followed by fine-needle aspiration cytology would be the preferred diagnostic modalities. Due to its low rate of malignant transformation and recurrence, the best treatment is local resection with follow-up as necessary.

Overexpression of the cell adhesion molecule claudin-9 is associated with invasion in pituitary oncocytomas

Pituitary oncocytoma is a subtype of nonfunctioning pituitary adenomas with the potential to be locally invasive. Currently, surgery is the most effective treatment, whereas functional pituitary adenomas can be treated by drugs. We analyzed the invasiveness of pituitary oncocytomas to identify biomarkers that may be useful for guiding future therapeutic decision making. To identify important biomarkers of pituitary oncocytomas, 20 oncocytomas that were negative for hormone-specific immunostaining were confirmed by anti-mitochondria antibody immunostaining and electron microscopy. Our clinical phenotype data showed a prominent male predilection (85%). These tumors were classified as invasive or noninvasive based on preoperative magnetic resonance imaging, intraoperative records, and pathology slide. We observed significantly different expression profiles between pituitary oncocytomas (n = 3) and normal pituitary glands (n = 3). A total of 1937 genes were differentially expressed between the pituitary oncocytomas and normal pituitary glands. Among these 1937 genes, 954 were up-regulated and 983 were down-regulated in pituitary oncocytomas. The most significantly altered gene, claudin-9 (CLDN9), was further confirmed by quantitative real-time polymerase chain reaction, Western blot, and immunohistochemical staining in 10 invasive pituitary oncocytoma samples and 10 noninvasive pituitary oncocytoma samples. High levels of CLDN9 were found in the pituitary oncocytomas, whereas low levels were detected in normal pituitary glands. In addition, the CLDN9 expression level was higher in invasive oncocytomas compared with noninvasive oncocytomas. Bioinformatics Gene Ontology analysis was performed to better understand the critical role of CLDN9 in the development and progression of oncocytomas. Consequently, CLDN9 may be an important biomarker for invasive pituitary oncocytomas.