Perineural spread is a well-known mechanism of dissemination of head and neck malignancies. There are few reports of melanoma involving the brachial plexus in the literature. To their knowledge, the authors report the first known case of perineural spread of malignant melanoma to the brachial plexus. Clinicoradiological and anatomopathological correlation is presented, highlighting the importance of peripheral nerve communications in perineural spread.
Carlos E. Restrepo, Robert J. Spinner, B. Matthew Howe, Mark E. Jentoft, Svetomir N. Markovic and Daniel H. Lachance
Ana C. Siquara de Sousa, Stepan Capek, Benjamin M. Howe, Mark E. Jentoft, Kimberly K. Amrami and Robert J. Spinner
Sciatic nerve endometriosis (EM) is a rare presentation of retroperitoneal EM. The authors present 2 cases of catamenial sciatica diagnosed as sciatic nerve EM. They propose that both cases can be explained by perineural spread of EM from the uterus to the sacral plexus along the pelvic autonomie nerves and then further distally to the sciatic nerve or proximally to the spinal nerves. This explanation is supported by MRI evidence in both cases. As a proof of concept, the authors retrieved and analyzed the original MRI studies of a case reported in the literature and found a similar pattern of spread. They believe that the imaging evidence of their institutional cases together with the outside case is a very compelling indication for perineural spread as a mechanism of EM of the nerve.
Desmond A. Brown, Nicholas L. Deep, Colin L. Driscoll, Michael J. Link, Mark E. Jentoft and David J. Daniels
Epstein-Barr virus–associated smooth-muscle tumors are rare tumors seen in immunocompromised patients. Most cases occur in the context of AIDS and organ transplantation, and very rarely in the setting of congenital immunodeficiency, with only 5 case reports of the latter published so far in the literature. The authors report the case of a previously healthy 8-year-old girl with headaches and precocious puberty who was found to have a large skull base lesion. There was a synchronous left adrenal lesion. She underwent resection of the skull base lesion and a left adrenalectomy. Thorough evaluation for immunodeficiency was negative for a known congenital immunodeficiency syndrome. She had a short course of intravenous immunoglobulin and has had no recurrence of disease or new lesions in the 17 months since presentation. Continued surveillance for the development of opportunistic infections and new or recurrent lesions is warranted in this case. Repeat surgery for surgically accessible tumors or chemoradiation would be recommended for any additional lesions.
Jonathan J. Stone, Nikhil K. Prasad, Pierre Laumonerie, B. Matthew Howe, Kimberly K. Amrami, Jodi M. Carter, Mark E. Jentoft and Robert J. Spinner
Desmoid-type fibromatosis (DTF) presents a therapeutic dilemma. While lacking metastatic potential, it is a locally aggressive tumor with a strong propensity for occurrence near nerve(s) and recurrence following resection. In this study, the authors introduce the association of an occult neuromuscular choristoma (NMC) identified in patients with DTF.
After experiencing a case of DTF found to have an occult NMC, the authors performed a retrospective database review of all other cases of biopsy-proven DTF involving the extremities or limb girdles in patients with available MRI data. Two musculoskeletal radiologists with expertise in peripheral nerve imaging reviewed the MRI studies of the eligible cases for evidence of previously unrecognized NMC.
The initial case of a patient with an occult sciatic NMC is described. The database review yielded 40 patients with DTF—18 (45%) in the upper limb and 22 (55%) in the lower limb. Two cases (5%) had MRI findings of NMC associated with the DTF, one in the proximal sciatic nerve and the other in the proximal tibial and sural nerves.
The coexistence of NMC may be under-recognized in a subset of patients with extremity DTF. This finding poses implications for DTF treatment and the likelihood of recurrence after resection or biopsy. Further study may reveal crucial links between the pathogenesis of NMC and DTF and offer novel therapeutic strategies.
Kathryn M. Van Abel, Grant W. Mallory, Jan L. Kasperbauer, M.D., Eric J. Moore, Daniel L. Price, Erin K. O’Brien, Kerry D. Olsen, William E. Krauss, Michelle J. Clarke, Mark E. Jentoft and Jamie J. Van Gompel
Swallowing dysfunction is common following transoral (TO) odontoidectomy. Preliminary experience with newer endoscopic transnasal (TN) approaches suggests that dysphagia may be reduced with this alternative. However, the reasons for this are unclear. The authors hypothesized that the TN approach results in less disruption of the pharyngeal plexus and anatomical structures associated with swallowing. The authors investigate the histological and gross surgical anatomical relationship between pharyngeal plexus innervation of the upper aerodigestive tract and the surgical approaches used (TN and TO). They also review the TN literature to evaluate swallowing outcomes following this approach.
Seven cadaveric specimens were used for histological (n = 3) and gross anatomical (n = 4) examination of the pharyngeal plexus with the TO and TN surgical approaches. Particular attention was given to identifying the location of cranial nerves (CNs) IX and X and the sympathetic chain and their contributions to the pharyngeal plexus. S100 staining was performed to assess for the presence of neural tissue in proximity to the midline, and fiber density counts were performed within 1 cm of midline. The relationship between the pharyngeal plexus, clivus, and upper cervical spine (C1-3) was defined.
Histological analysis revealed the presence of pharyngeal plexus fibers in the midline and a significant reduction in paramedian fiber density from C-2 to the lower clivus (p < 0.001). None of these paramedian fibers, however, could be visualized with gross inspection or layer-by-layer dissection. Laterally based primary pharyngeal plexus nerves were identified by tracing their origins from CNs IX and X and the sympathetic chain at the skull base and following them to the pharyngeal musculature. In addition, the authors found 15 studies presenting 52 patients undergoing TN odontoidectomy. Of these patients, only 48 had been swallowing preoperatively. When looking only at this population, 83% (40 of 48) were swallowing by Day 3 and 92% (44 of 48) were swallowing by Day 7.
Despite the midline approach, both TO and TN approaches may injure a portion of the pharyngeal plexus. By limiting the TN incision to above the palatal plane, the surgeon avoids the high-density neural plexus found in the oropharyngeal wall and limits injury to oropharyngeal musculature involved in swallowing. This may explain the decreased incidence of postoperative dysphagia seen in TN approaches. However, further clinical investigation is warranted.