title: Paraneoplastic syndromes (PNS) associated with Merkel cell carcinoma (MCC): A case series of 8 patients highlighting different clinical manifestations.
abstract: BACKGROUND
  Paraneoplastic syndromes (PNS) are commonly associated with neuroendocrine cancers, such as small cell lung cancer.
  
  
  OBJECTIVE
  We examined the association of PNS in Merkel cell carcinoma (MCC), a rare neuroendocrine skin cancer.
  
  
  METHODS
  We identified PNS associated with MCC based on chart review of a Seattle-based repository and examined the incidence of MCC-associated hyponatremia in an independent cohort within Kaiser Permanente Northern California.
  
  
  RESULTS
  Eight PNS cases were identified from the Seattle repository. Three distinct PNS types were observed: cerebellar degeneration (1 case), Lambert-Eaton myasthenic syndrome (2 cases), and malignancy-associated hyponatremia (5 cases). Moreover, the incidence of severe hyponatremia (serum sodium <125 mmol/L) coincident with MCC was identified among 4.3% (9 of 211) patients with MCC in the Kaiser Permanente Northern California cohort.
  
  
  CONCLUSIONS
  We did not have access to complete medical records on all patients so it was not possible to determine the prevalence of PNS in MCC.
  
  
  CONCLUSIONS
  MCC can be associated with PNS similar to those found in other neuroendocrine cancers. Clinicians should be aware of these presentations as PNS often precede the identification of the underlying malignancy and usually resolve with appropriate treatment of the cancer.
authors.affiliation: Dermatology Division, Department of Medicine, University of Washington, Seattle, Washington.
authors.forename: Jayasri G
authors.initials: JG
authors.lastname: Iyer
authors.affiliation: Dermatology Division, Department of Medicine, University of Washington, Seattle, Washington.
authors.forename: Kaushik
authors.initials: K
authors.lastname: Parvathaneni
authors.affiliation: Medical Oncology Division, Department of Medicine, University of Washington, Seattle, Washington.
authors.forename: Shailender
authors.initials: S
authors.lastname: Bhatia
authors.affiliation: Dermatology Division, Department of Medicine, University of Washington, Seattle, Washington.
authors.forename: Erica S
authors.initials: ES
authors.lastname: Tarabadkar
authors.affiliation: Dermatology Division, Department of Medicine, University of Washington, Seattle, Washington.
authors.forename: Astrid
authors.initials: A
authors.lastname: Blom
authors.affiliation: Dermatology Division, Department of Medicine, University of Washington, Seattle, Washington.
authors.forename: Ryan
authors.initials: R
authors.lastname: Doumani
authors.affiliation: Dermatology Division, Department of Medicine, University of Washington, Seattle, Washington.
authors.forename: Jill
authors.initials: J
authors.lastname: McKenzie
authors.affiliation: Division of Research, Kaiser Permanente Northern California, Oakland, California; Department of Dermatology, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Maryam M
authors.initials: MM
authors.lastname: Asgari
authors.affiliation: Dermatology Division, Department of Medicine, University of Washington, Seattle, Washington. Electronic address: pnghiem@uw.edu.
authors.forename: Paul
authors.initials: P
authors.lastname: Nghiem
mesh_terms: D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D015266:Carcinoma, Merkel Cell / Q000175:diagnosis* / Q000453:epidemiology / Q000601:surgery; D015897:Comorbidity; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D010257:Paraneoplastic Syndromes / Q000175:diagnosis* / Q000453:epidemiology* / Q000628:therapy; D011379:Prognosis; D012042:Registries; D018570:Risk Assessment; D012494:Sampling Studies; D017678:Sex Distribution; D012878:Skin Neoplasms / Q000175:diagnosis* / Q000453:epidemiology / Q000628:therapy; D016019:Survival Analysis
keywords: Lambert-Eaton myasthenic syndrome; Merkel cell carcinoma; cerebellar degeneration; malignancy-associated hyponatremia; neuroendocrine; paraneoplastic syndrome