title: True thymic hyperplasia versus follicular thymic hyperplasia: a retrospective analysis of 13 cases.
abstract: BACKGROUND
  Thymic enlargement is a rare phenomenon that can be challenging.
  
  
  METHODS
  We present a retrospective study over a 13-year period (from 1996 to 2008) of 13 cases of thymic hyperplasia that included 4 cases of true thymic hyperplasia (TTH) and 9 cases of follicular thymic hyperplasia (FTH).
  
  
  OBJECTIVE
  To describe the pathogenesis and different associations of these 2 entities; to emphasize the difficulties in accurate diagnosis without histological examination and to report an unusual association between TTH and cutaneous leishmaniasis.
  
  
  RESULTS
  There were 9 women and 4 men. All patients with FTH had a past medical history of myasthenia gravis (MG). In the group of TTH, 2 patients received chemotherapy and one patient had been administered amphotericin B for a cutaneous leishmaniasis. Radiologic findings showed a mediastinal mass in 7 cases. Thymectomy was performed in all patients with FTH and in one patient with TTH and suspect malignant disease. We observed no complications in any case.
  
  
  CONCLUSIONS
  The two main types of thymic hyperplasia have different pathogenic characteristics and diverse treatment modalities.
authors.affiliation: Department of Pathology, Abderrahmen Mami Hospital, 2080 Ariana, Tunisia. mlika.zorgati.mona@hotmail.com
authors.forename: M
authors.initials: M
authors.lastname: Mlika
authors.forename: A
authors.initials: A
authors.lastname: Ayadi-Kaddour
authors.forename: A
authors.initials: A
authors.lastname: Marghli
authors.forename: O
authors.initials: O
authors.lastname: Ismail
authors.forename: T
authors.initials: T
authors.lastname: Kilani
authors.forename: F
authors.initials: F
authors.lastname: El Mezni
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D005260:Female; D006801:Humans; D016773:Leishmaniasis, Cutaneous / Q000150:complications; D008297:Male; D008875:Middle Aged; D009157:Myasthenia Gravis / Q000150:complications; D012189:Retrospective Studies; D013952:Thymus Hyperplasia / Q000150:complications / Q000473:pathology*; D055815:Young Adult