title: Oral Spindle Cell Lipoma in a Rare Location: A Differential Diagnosis.
abstract: BACKGROUND
  Spindle cell lipoma (SCL) is an uncommon and histologically distinct variant of lipoma. It usually occurs as a solitary, subcutaneous, and well-circumscribed lesion in the posterior neck, shoulders, and back of older men. SCL of the oral cavity is rare. We present the clinical-pathologic features of the third case of SCL located on the hard palate and discuss the histological differential diagnosis with other fusiform neoplasms.
  
  
  METHODS
  A 56-year-old man was evaluated for an asymptomatic swelling on the right side of the hard palate. The intraoral examination showed a 25×20 mm sessile and circumscribed tumor, underlying an apparently healthy mucosa of normal color. The lesion revealed a floating consistency during palpation. Excisional biopsy was carried out based on a clinical diagnosis of lipoma or a benign minor salivary gland tumor. The histopathology demonstrated a well-circumscribed but unencapsulated proliferation of bland spindle cells admixed with mature adipocytes in a collagenous/myxoid stroma. The spindle cells were uniform, exhibiting elongated nuclei and narrow cytoplasmic processes without atypia. They were positive to CD34 and negative to factor VIII, alpha-smooth muscle actin, S100, cytokeratin, and actin. Mitotic activity was low, as confirmed by Ki-67 immunostaining. No lipoblastic activity was found. The diagnosis of SCL was therefore established.
  
  
  CONCLUSIONS
  Oral spindle cell lipoma is a rare benign lipomatous tumor. The histologic picture shows a range of variations and the observation of morphological features is important to distinguish this lesion from other fusiform tumors. Immunohistochemistry should be helpful in this differentiation.
authors.affiliation: Department of Oral Pathology and Surgery, School of Dentistry, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
authors.forename: Filipe
authors.initials: F
authors.lastname: Jaeger
authors.affiliation: Department of Oral Pathology and Surgery, School of Dentistry, Pontifícia Universidade Católica de Minas Gerais, Belo Horizonte, MG, Brazil.
authors.forename: Hermínia Marques
authors.initials: HM
authors.lastname: Capistrano
authors.affiliation: Department of Oral Pathology and Surgery, School of Dentistry, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
authors.forename: Wagner Henriques
authors.initials: WH
authors.lastname: de Castro
authors.affiliation: Department of Oral Pathology and Surgery, School of Dentistry, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
authors.forename: Patrícia Carlos
authors.initials: PC
authors.lastname: Caldeira
authors.affiliation: Department of Oral Pathology and Surgery, School of Dentistry, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
authors.forename: Maria Auxiliadora
authors.initials: MA
authors.lastname: Vieira do Carmo
authors.affiliation: Department of Oral Pathology and Surgery, School of Dentistry, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
authors.forename: Ricardo Alves
authors.initials: RA
authors.lastname: de Mesquita
authors.affiliation: Department of Oral Pathology and Surgery, School of Dentistry, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
authors.forename: Maria Cássia
authors.initials: MC
authors.lastname: Ferreira de Aguiar
mesh_terms: D001706:Biopsy; D003937:Diagnosis, Differential; D006801:Humans; D008067:Lipoma / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D009061:Mouth Mucosa / Q000473:pathology*; D009062:Mouth Neoplasms / Q000175:diagnosis*