title: Pleural "drop metastases" 21 years after resection of a thymoma.
abstract: We describe an unusual case of pleural drop metastases 21 years after complete resection of an encapsulated thymoma in a Southeast Asian patient with myasthenia gravis (MG).
  
  
  
  This investigation includes a case report and brief review of the literature.
  
  
  
  The patient presented in 2015 with generalized weakness, fatigue, and shortness of breath, but no diplopia, ptosis, dysphagia, or dysarthria. Because these symptoms were atypical for an MG exacerbation, a de-novo work-up was performed. Chest computed tomography (CT) showed numerous pleural nodules ("drop metastases"), and CT-guided biopsy revealed metastatic thymoma.
  
  
  
  The average disease-free interval for thymoma ranges from 68 to 86 months. Pleural and mediastinal recurrence are more common than distant hematogenous recurrence. Adverse prognostic factors include an initial higher Masaoka stage, incomplete resection, older age, and pleural or pericardial involvement. Despite apparent complete resection of thymoma, clinicians should remain vigilant for recurrence for as long as 20 years after initial management. Long-term follow-up with radiologic surveillance is recommended. Muscle Nerve 56: 171-175, 2017.
authors.affiliation: Department of Neurology, Mayo Clinic, Scottsdale, Arizona, USA.
authors.forename: Chia-Chun
authors.initials: CC
authors.lastname: Chiang
authors.affiliation: Department of Neurology, Mayo Clinic, Scottsdale, Arizona, USA.
authors.forename: Angela M
authors.initials: AM
authors.lastname: Parsons
authors.affiliation: Department of Radiology, Mayo Clinic, Phoenix, Arizona, USA.
authors.forename: J Scott
authors.initials: JS
authors.lastname: Kriegshauser
authors.affiliation: Department of Hematology/Oncology, Mayo Clinic, Scottsdale, Arizona, USA.
authors.forename: Harshita R
authors.initials: HR
authors.lastname: Paripati
authors.affiliation: Department of Pathology, Mayo Clinic, Scottsdale, Arizona, USA.
authors.forename: Matthew A
authors.initials: MA
authors.lastname: Zarka
authors.affiliation: Department of Neurology, Mayo Clinic, Scottsdale, Arizona, USA.|Center for Neuroscience and Neurological Recovery, Methodist Rehabilitation Center, 1350 E. Woodrow Wilson Drive, Jackson, Mississippi, 39216, USA.
authors.forename: A Arturo
authors.initials: AA
authors.lastname: Leis
mesh_terms: D000328:Adult; D006801:Humans; D008297:Male; D010997:Pleural Neoplasms / Q000209:etiology* / Q000556:secondary*; D049268:Positron-Emission Tomography; D011183:Postoperative Complications / Q000000981:diagnostic imaging; D013934:Thymectomy / Q000009:adverse effects*; D013945:Thymoma / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D013953:Thymus Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D014057:Tomography, X-Ray Computed
keywords: disease surveillance; disease-free survival; drop metastases; myasthenia gravis; recurrence; thymoma