title: Spindle cell lipoma of the oral cavity. Report of a rare intramuscular case with fine needle aspiration findings.
abstract: BACKGROUND
  Spindle cell lipoma (SCL) is a benign neoplasm characterized by a mixture of mature fat, bland spindle cells and wiry collagen in a variably myxoid background. Oral SCLs are rare, and only four cases of intramuscular SCL exist in the literature. We report the first case of intramuscular SCL of the oral cavity with fine needle aspiration (FNA) findings.
  
  
  METHODS
  A 61-year-old woman presented with a 3-cm mass in the right gingivobuccal sulcus. Papanicolaoustained FNA smears were hypocellular and contained loose collections of spindle cells in a myxoid background, numerous mast cells, rare capillary fragments and portions of skeletal muscle. The spindle cells had mild nuclear enlargement, focal nuclear irregularities, rare intranuclear inclusions and occasional small nucleoli. No lipoblasts or mitoses were identified. There was intermingling of the spindle cells with the skeletal muscle fragments.
  
  
  CONCLUSIONS
  Intraoral SCL is a rare lesion but should be considered in the differential for a benign spindle cell neoplasm in the oral cavity. Clues to diagnosis on cytology include mature fat, bland spindle cells, a myxoid background and mast cells.
authors.affiliation: Department of Cytopathology and Pathology, Harborview Medical Center and University of Washington Medical Center, Seattle, Washington, USA. agoff@u.washington.edu
authors.forename: S N
authors.initials: SN
authors.lastname: Agoff
authors.forename: A L
authors.initials: AL
authors.lastname: Folpe
authors.forename: V S
authors.initials: VS
authors.lastname: Grieco
authors.forename: R L
authors.initials: RL
authors.lastname: Garcia
mesh_terms: D001707:Biopsy, Needle; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008067:Lipoma / Q000473:pathology*; D008080:Liposarcoma / Q000175:diagnosis; D008407:Mast Cells / Q000166:cytology; D008875:Middle Aged; D009062:Mouth Neoplasms / Q000473:pathology*; D019042:Muscle Neoplasms / Q000473:pathology*; D009361:Neoplasm Invasiveness