Koutlas, Ioannis G.

The authors describe the case of an intraneural ganglion cyst involving a cranial nerve (V3), which was found to have a joint connection in support of an articular origin within the cranial nerves. An inferior alveolar intraneural cyst was incidentally discovered on a plain radiograph prior to edentulation. It was resected from within the mandibular canal with no joint connection perceived at surgery. Histologically, the cyst was confirmed to be an intraneural ganglion cyst. Reinterpretation of the preoperative CT scan showed the cyst arising from the temporomandibular joint. This case is consistent with the articular (synovial) theory of intraneural ganglion cysts. An anatomical explanation and potential joint connection are provided for this case as well as several other cases of intraneural cysts in the literature, and thus unifying cranial nerve involvement with accepted concepts of intraneural ganglion cyst formation and propagation.

AimsThe pathogenesis of intraosseous mucoepidermoid carcinoma (IMEC) remains unknown. Coexistence with odontogenic cysts (ODC) has been reported in 32–48% of IMEC. Furthermore, prosoplastic mucous cells are often seen in the epithelial lining of ODCs. MECT1–MAML2 fusion transcripts have been identified in >66% of salivary gland MEC cases. The aim of this study was to investigate the presence of MAML2 rearrangement in ODCs featuring mucous prosoplasia.Methods and resultsTen cases of ODC with a mucous cell component and three cases of IMEC were evaluated using fluorescence in‐situ hybridization. All cases occurred in the mandible. The ODCs exhibited a M:F ratio of 4:1 (mean age 49.2 years), while all IMECs occurred in women (mean age 68.3 years). All three IMECs demonstrated MAML2 rearrangement, in 26–61% of tumour cells. Successful hybridization was observed in nine of 10 cases of ODC. In two of these nine, there was MAML2 rearrangement in 12% and 24% of the lining epithelial cells, while three of the nine showed rearrangement in 7–8% of cells; the remaining four cases were negative.ConclusionsWe identified MAML2 rearrangements in five of nine ODCs lined by mucus‐secreting cells. This suggests that at least a subset of ODCs with mucous prosoplasia are characterized by molecular events considered diagnostic for intraosseous and extraosseous MEC.