title: Pituitary adenoma with adipose tissue: A new metaplastic variant.
abstract: Pituitary adenomas are benign tumors representing approximately 15-20% of intracranial neoplasms. There have been few reports of metaplastic osseous transformation and about 60 cases of neuronal metaplasia in pituitary adenoma but adipose metaplasia has not been previously described in the English literature. Here we report a case of pituitary adenoma with metaplastic adipose tissue in a 58-year-old male patient. Histologically this case fulfilled the criteria of a non-functioning pituitary adenoma, and moreover a central area of adipose tissue, made by mature adipocytes, and many tumor cells, containing fat droplet were evident. Lipomatous transformation of tumor cells in the CNS has been previously observed but, to the best of our knowledge, our case is the first pituitary adenoma with such change. The histogenesis of the adipose element in pituitary adenoma is not well understood, and could be a result of a metaplastic change or divergent differentiation from a common progenitor cell.
authors.affiliation: Pathology Unit, Anna Meyer Children's University Hospital, Florence, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Caporalini
authors.affiliation: Pathology Unit, Anna Meyer Children's University Hospital, Florence, Italy.
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: Buccoliero
authors.affiliation: Neurosurgery Unit, Careggi University Hospital, Florence, Italy.
authors.forename: Luigi
authors.initials: L
authors.lastname: Pansini
authors.affiliation: Pathology Unit, Anna Meyer Children's University Hospital, Florence, Italy.
authors.forename: Selene
authors.initials: S
authors.lastname: Moscardi
authors.affiliation: Pathology Unit, Careggi University Hospital, Florence, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Novelli
authors.affiliation: Pathology Unit, Careggi University Hospital, Florence, Italy.
authors.forename: Gianna
authors.initials: G
authors.lastname: Baroni
authors.affiliation: Neurosurgery Unit, Careggi University Hospital, Florence, Italy.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Bordi
authors.affiliation: Neurosurgery Unit, Careggi University Hospital, Florence, Italy.
authors.forename: Franco
authors.initials: F
authors.lastname: Ammannati
authors.affiliation: Pathology Unit, Careggi University Hospital, Florence, Italy.
authors.forename: Gian Luigi
authors.initials: GL
authors.lastname: Taddei
mesh_terms: D000236:Adenoma / Q000473:pathology*; D000273:Adipose Tissue / Q000473:pathology*; D006801:Humans; D008297:Male; D008679:Metaplasia / Q000473:pathology; D008875:Middle Aged; D010911:Pituitary Neoplasms / Q000473:pathology*
keywords: adenoma; adipose tissue; fat droplets; metaplasia; pituitary