{
  "abstract": "Background Contactin-associated protein-like 2 (CASPR2) antibodies are associated with various peripheral and central nervous system syndromes including peripheral nerve hyperexcitability, neuropathic pain and limbic encephalitis. A paraneoplastic association is identified in 20–30% of cases of CASPR2 antibody associated syndromes. This case describes the novel association of a CASPR2 antibody associated peripheral nerve syndrome and a spermatocytic testicular tumour.Case Presentation A 62-year-old male presented with a 3-month history of painful progressive sensory disturbance associated with 13kgs of unintentional weight loss, and mild cognitive slowing with personality changes. His only significant history was a 40-pack-year smoking history.Examination showed trophic skin changes below the mid-shin, reduced small fibre sensation to the mid-shin and reduced large fibre sensation to the ankle. Power was normal though ankle reflexes were diminished.Nerve conduction studies revealed an axonal predominant sensorimotor neuropathy with prolonged tibial F waves and associated after-discharges. Electromyogram was normal.CASPR2 antibodies were positive in CSF and serum. CSF protein was 0.46 g/dL with normal cell count and negative oligoclonal bands. Routine neuropathy workup was unremarkable aside from a weakly positive speckled pattern ANA.Testicular ultrasound and pelvic MRI identified an enlarged right testis with cystic changes. Right orchidectomy confirmed a spermatocytic tumour confined to the right testis. Post-orchidectomy positron emission topography was normal.The presence of a typical CASPR2 associated syndrome and unintentional weight loss in the setting of spermatocytic tumour were in keeping with a paraneoplastic syndrome.Conclusion Spermatocytic testicular tumours may be associated with CASPR2 antibody mediated paraneoplastic syndromes.",
  "authors": [
    {
      "affiliations": [
        "Flinders Medical Centre, Bedford Park, SA, Australia",
        "University of Adelaide, Adelaide, SA, Australia"
      ],
      "name": "Piyanit Wijaithum"
    },
    {
      "affiliations": [
        "Flinders Medical Centre, Bedford Park, SA, Australia"
      ],
      "name": "Lachlan Tamlin"
    },
    {
      "affiliations": [
        "Flinders Medical Centre, Bedford Park, SA, Australia"
      ],
      "name": "Mhapamkar Kunal"
    },
    {
      "affiliations": [
        "Flinders Medical Centre, Bedford Park, SA, Australia"
      ],
      "name": "Shaddy El-Masri"
    },
    {
      "affiliations": [
        "Flinders Medical Centre, Bedford Park, SA, Australia"
      ],
      "name": "David Schultz"
    },
    {
      "affiliations": [
        "Flinders Medical Centre, Bedford Park, SA, Australia",
        "University of Adelaide, Adelaide, SA, Australia"
      ],
      "name": "James Triplett"
    }
  ],
  "title": "3686 CASPR2-antibody peripheral nerve hyperexcitability associated with a spermatocytic testicular tumour",
  "uid": "e756ec5c-3079-54e9-a076-29d3a3ab33f6"
}