title: Microcystic/reticular Schwannoma: morphological features causing diagnostic dilemma on fine-needle aspiration cytology.
abstract: BACKGROUND
  Schwannoma is a common, benign, peripheral nerve sheath tumor. Fine-needle aspiration (FNA) has been very useful for diagnosing classic Schwannoma. Recently, a new morphological variant, the so-called microcystic/reticular Schwannoma, has been recognized. Although histological features of microcystic/reticular Schwannoma have been described, there are no available reports on its FNA cytological appearance.
  
  
  METHODS
  A 28-year-old male presented with right arm and finger tingling and numbness. Physical examination found a right lower neck mass. He underwent FNA, followed by needle core biopsy. A diagnosis of microcystic/reticular schwannoma was made. In this case report, we focused on the FNA diagnostic features, thoroughly searched the literature, and discussed relevant information for differential diagnosis.
  
  
  CONCLUSIONS
  Unlike classic Schwannoma, microcystic/reticular variant has unique cytological features which can mimic those of several morphologically similar mass lesions, making the FNA interpretation more challenging. Cytopathologists should be aware of this new variant of Schwannoma when evaluating FNA cytology of mass lesions showing low-grade, paucicellular, and myxoid features.
authors.affiliation: Department of Pathology, University Hospitals of Cleveland and Case Western Reserve University School of Medicine, Cleveland, USA.
authors.forename: Shunyou
authors.initials: S
authors.lastname: Gong
authors.affiliation: Department of Pathology, University Hospitals of Cleveland and Case Western Reserve University School of Medicine, Cleveland, USA.
authors.forename: Said
authors.initials: S
authors.lastname: Hafez-Khayyata
authors.affiliation: Department of Pathology, University Hospitals of Cleveland and Case Western Reserve University School of Medicine, Cleveland, USA.
authors.forename: Wei
authors.initials: W
authors.lastname: Xin
mesh_terms: D000328:Adult; D044963:Biopsy, Fine-Needle / Q000379:methods*; D003581:Cytodiagnosis; D003937:Diagnosis, Differential; D006801:Humans; D008297:Male; D009442:Neurilemmoma / Q000175:diagnosis*; D010524:Peripheral Nervous System Neoplasms / Q000175:diagnosis*