Rare Diseases of the Salivary Glands and of Facial Nerve

Mucosa-Associated Lymphoid Tissue Lymphoma of the Sublingual Salivary Gland: A Case Report

Mucosa-associated lymphoid tissue (MALT) lymphoma is a type of B-cell lineage lymphoma that can affect the head and neck region. This report presents a rare case of an extra-nodal marginal zone B-cell MALT lymphoma of a sublingual gland, diagnosed in an 18-year-old male patient. The patient had a history of ranula surgical removal on the right side of the mouth. One year after surgery, the patient presented with complaints of swelling of the left parotid gland, with no significant changes found during the examination and a self-resolving outcome. Subsequently, two years later, the patient began to complain of a fast-growing cyst under the tongue. A surgical excision of the left sublingual gland and the ranula was performed, and a final diagnosis of MALT lymphoma was rendered. The patient was referred to the department of hematology for further treatment planning and follow-up.

MALDI Mass Spectrometry Imaging Highlights Specific Metabolome and Lipidome Profiles in Salivary Gland Tumor Tissues

Salivary gland tumors are relatively uncommon neoplasms that represent less than 5% of head and neck tumors, and about 90% are in the parotid gland. The wide variety of histologies and tumor characteristics makes diagnosis and treatment challenging. In the present study, Matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) was used to discriminate the pathological regions of patient-derived biopsies of parotid neoplasms by metabolomic and lipidomic profiles. Fresh frozen parotid tissues were analyzed by MALDI time-of-flight (TOF) MSI, both in positive and negative ionization modes, and additional MALDI-Fourier-transform ion cyclotron resonance (FT-ICR) MSI was carried out for metabolite annotation. MALDI-TOF-MSI spatial segmentation maps with different molecular signatures were compared with the histologic annotation. To maximize the information related to specific alterations between the pathological and healthy tissues, unsupervised (principal component analysis, PCA) and supervised (partial least squares-discriminant analysis, PLS-DA) multivariate analyses were performed presenting a 95.00% accuracy in cross-validation. Glycerophospholipids significantly increased in tumor tissues, while sphingomyelins and triacylglycerols, key players in the signaling pathway and energy production, were sensibly reduced. In addition, a significant increase of amino acids and nucleotide intermediates, consistent with the bioenergetics request of tumor cells, was observed. These results underline the potential of MALDI-MSI as a complementary diagnostic tool to improve the specificity of diagnosis and monitoring of pharmacological therapies.