Clinicopathologic Findings in Patients With Paraneoplastic Neuropathies and Antibodies Strongly Associated With Cancer.

BACKGROUND AND OBJECTIVES: Pathologic descriptions of peripheral nerve involvement in paraneoplastic neuropathies are sparse, mostly from autopsies focusing on CNS and dorsal root ganglia tissues. Here, we describe the clinicopathologic features of peripheral nerve biopsies in patients with paraneoplastic neurologic syndromes to expand the currently limited knowledge. METHODS: Retrospective review of the Mayo Clinic electronic medical record from 1995 to 2022 for patients identified to have subacute onset neuropathy with paraneoplastic antibodies identified in our neuroimmunology laboratory having available nerve biopsies performed at the time of diagnosis. Patients with another cause of neuropathy not linked to their subacute onset were excluded. RESULTS: Nineteen patients met inclusion criteria: 4 with amphiphysin antibodies, 6 with antineuronal nuclear antibody (ANNA)-1 only, 3 with both ANNA-1 and collapsin response-mediator protein 5 (CRMP-5), 2 with ANNA-2, and 4 with CRMP-5 antibodies only. Fifteen biopsies had reduced the density of myelinated nerve fibers-4 with multifocality. Subperineurial edema was present in 17 biopsies. Prominent epineurial perivascular inflammation was present in 3 biopsies, all belonging to patients with a lumbosacral radiculoplexus neuropathy (LRPN) phenotype. DISCUSSION: Axonal loss, subperineurial edema, and an absence of prominent inflammation are the most common findings in nerve biopsies of patients with paraneoplastic antibodies strongly associated with cancer. The LRPN phenotype was the only subset with inflammatory collections. Paraneoplastic autoantibody testing should be considered in patients with subacute onset neuropathies, with or without interstitial inflammatory findings.

Anterolateral Triangle: A Cadaveric Study with Neurosurgical Significance.

The anterolateral triangle is one of 10 surgical triangles of the cavernous sinus and serves as an important anatomic landmark for the skull base surgeon. There are few studies in the English literature that have precisely defined and measured the borders of the anterolateral triangle and little agreement has been made regarding the nomenclature within the English literature. A total of 12 midsagittally hemisected adult human cadaveric head halves were dissected to expose the anterolateral triangle. The triangle was defined and measurements of the anterior, posterior, and lateral borders were taken. The mean lengths and standard deviations of the anterior, posterior, and lateral borders were 8.3 ± 2.2 mm, 5.9 ± 2.0 mm, and 11.5 ± 2.9 mm, respectively. The mean area and standard deviation were 20.46 ± 9.30 mm2. The anterolateral triangle is helpful in understanding and planning surgical approaches to the cavernous sinus and middle cranial fossa. As such, normal anatomic relationships and the sizes of the anterolateral triangle must first be recognized to better access the pathologic changes within and around this region.