title: Abnormal distribution and hyperplasia of thyroid C-cells in PTEN-associated tumor syndromes.
abstract: BACKGROUND
  Cowden's disease (CD) and Bannayan-Ruvalcaba-Riley syndrome (BRRS) are allelic disorders characterized by multiple hamartomatous overgrowths of the thyroid, breast, skin, and gastrointestinal tract, and an increased risk of developing benign and malignant tumors of the breast and thyroid gland, secondary to germline point mutations in the PTEN gene. In contrast to thyroid epithelial lesions, abnormalities of the C-cells are currently not considered part of the spectrum of manifestations seen in PTEN-associated syndromes.
  
  
  METHODS
  The thyroid glands from two patients with overlapping CD/BRRS phenotypes, and with distinct PTEN mutations, were entirely submitted for histopathological examination, calcitonin immunostaining and C-cell mapping.
  
  
  RESULTS
  Multiple follicular adenomas and adenomatous nodules were present in the thyroid glands from both patients. A microscopic focus of papillary carcinoma was also present in one gland. C-cell hyperplasia was documented in both cases by calcitonin immunostaining.
  
  
  CONCLUSIONS
  PTEN-associated tumor syndromes should be considered in the differential diagnosis of C-cell hyperplasia of the thyroid.
authors.affiliation: Department of Pathology, Children's Hospital Boston, Harvard Medical School, Boston, MA 02115, USA.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Zambrano
authors.forename: Ingrid
authors.initials: I
authors.lastname: Holm
authors.forename: Jonathan
authors.initials: J
authors.lastname: Glickman
authors.forename: Stephen
authors.initials: S
authors.lastname: Huang
authors.forename: Antonio
authors.initials: A
authors.lastname: Perez-Atayde
authors.forename: Harry P W
authors.initials: HP
authors.lastname: Kozakewich
authors.forename: Robert C
authors.initials: RC
authors.lastname: Shamberger
authors.forename: Vânia
authors.initials: V
authors.lastname: Nosé
mesh_terms: D018263:Adenocarcinoma, Follicular / Q000473:pathology*; D000236:Adenoma / Q000473:pathology*; D000293:Adolescent; D000328:Adult; D002116:Calcitonin / Q000378:metabolism; D002648:Child; D003937:Diagnosis, Differential; D005260:Female; D006223:Hamartoma Syndrome, Multiple / Q000473:pathology*; D006801:Humans; D006965:Hyperplasia / Q000473:pathology*; D007150:Immunohistochemistry; D008297:Male; D009154:Mutation; D051059:PTEN Phosphohydrolase; D010744:Phosphoric Monoester Hydrolases / Q000235:genetics; D013961:Thyroid Gland / Q000166:cytology; D013964:Thyroid Neoplasms / Q000473:pathology*; D025521:Tumor Suppressor Proteins / Q000235:genetics
chemical_list: D025521:Tumor Suppressor Proteins; D002116:Calcitonin; D010744:Phosphoric Monoester Hydrolases; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human