Pleura & peritoneum

Peritoneum

Adenomatoid tumor



Last author update: 1 February 2016
Last staff update: 9 June 2023

Copyright: 2003-2024, PathologyOutlines.com, Inc.

PubMed Search: Adenomatoid tumor

Joseph Peevey, M.D.
Rouba Ali-Fehmi, M.D.
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Cite this page: Peevy J, Abdulfatah E, Ali-Fehmi R, Bandyopadhyay S, Shi DP. Adenomatoid tumor. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/pleuraperitoneumadenomatoid.html. Accessed March 29th, 2024.
Definition / general
  • Benign lesion, often incidental finding on oophorectomy specimen
  • More frequently these lesion are found in males (epididymis, spermatic cord and testicular membrane); however, in females lesions are seen more commonly in fallopian tubes, broad ligament and uterus
  • Thought to arise from mesothelial serosal cells
  • First described by Golden and Ash in 1945 (Am J Pathol 1945;21:63)
Essential features
  • Rarely found within ovary
  • Typically small with 0.5 - 3 cm incidental lesions near hilum
Terminology
  • Previously known as benign mesothelioma of the genital tract
Epidemiology
Sites
  • Ovarian and juxtaovarian sites are rare
  • Occur predominantly at the ovarian hilum and may extend into and replace the ovarian parenchyma
  • Most frequently unilateral, found within fallopian tube, broad ligament or on uterine serosal surface
Pathophysiology / etiology
Clinical features
  • Asymptomatic, discovered as an incidental finding
  • Usually 0.5 - 3.0 cm, rarely larger and symptomatic
Diagnosis
  • Histologic recognition, confirmed by immunophenotype
  • Often incidental
Laboratory
Radiology description
  • Not routinely performed for primary diagnosis
  • Case reports describe incidental lesions on transvaginal ultrasound displaying multilocular cystic mass often with vascularized central / solid portion
  • Radiographic differential diagnosis, if provided, may include epithelial tumors, inclusion peritoneal cysts, and multiple large follicles
  • CT imaging seldom describes lesion (J Clin Ultrasound 2005;33:233)
Prognostic factors
  • Benign behavior, no reports of recurrence or malignant transformation
Case reports
Treatment
  • Excision results in complete cure
  • Recurrence after excision is rare
Gross description
  • Small, round to oval, well circumscribed tumor
  • Cut surface may have small cystic spaces
Microscopic (histologic) description
  • Composed of clefts and spaces lined by cuboidal, low columnar or flattened epithelial-like cells
  • Surrounded by connective tissue that varies from loose and edematous to dense and hyalinized
  • The epithelial-like cells may exhibit marked vacoulation, which in some cases may contain weakly basophilic material
  • A spotty lymphoid aggregate may be a low power clue to the diagnosis
  • Distinctive thread-like bridging strands crossing the tubular spaces are useful diagnostic features
  • Morphologic patterns:
    • Adenoid
    • Angiomatoid
    • Cystic
    • Glandular
    • Solid
    • Tubular
    • Plexiform
    • Canalicular
  • Similar appearance to appearance found within other locations
  • Relatively well demarcated, nonencapsulated solid aggregates of cells forming cleft-like spaces lined by low columnar to cuboidal flattened epithelial-like cells
  • Cells often surrounded by stroma that ranges from dense / fibrotic to loose / edematous
  • Epithelial-like cells may display marked vacuolization, signet ring cell-like appearance or oxyphilic cytoplasm
Microscopic (histologic) images

Contributed by Eman Abdulfatah, M.D., AFIP and @AnaPath10 on Twitter
Adenoid pattern Adenoid pattern

Adenoid pattern

Adenoid pattern Adenoid pattern

Adenoid pattern


Angiomatoid pattern Angiomatoid pattern

Angiomatoid pattern

Trabecular pattern Trabecular pattern

Trabecular pattern,


Scattered cysts

Scattered cysts

Adenomatoid tumor

Cytology description
  • Smears are moderately cellular with sheets of monotonous round to oval cells showing indistinct cell borders and moderate to abundant pale cytoplasm with vacuolations
  • Nuclei are eccentric in location, but regular with inconspicuous nucleoli
Positive stains
Negative stains
Electron microscopy description
  • No microvilli, no bundles of cytoplasmic filaments, no tight junctional complexes, no intercellular spaces
Molecular / cytogenetics description
  • No specific genetic abnormality has been identified
Differential diagnosis
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