Stromal tumors
Adenomatoid tumor

Author: Laura Ardighieri, M.D. (see Authors page)
Editor: Ayse Ayhan, M.D., Ph.D.

Revised: 22 October 2016, last major update October 2016

Copyright: (c) 2002-2016, PathologyOutlines.com, Inc.

PubMed search: adenomatoid tumor uterus
Cite this page: Adenomatoid tumor. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/uterusadenomatoid.html. Accessed October 24th, 2016.
Definition / General
  • Benign tumor of mesothelial origin
Essential Features
  • Synonyms: benign mesothelioma, benign mesothelial tumor, benign adenomatoid mesothelioma
ICD-10 coding
  • 9054 / 0
  • Reproductive aged women, mean 45 years, range 24 - 72 years
  • Sites
    • Neoplastic rather than reactive (based on molecular, clinical and pathological features)
    Clinical Features
    • By histopathology
    • Routine hematological and biochemical parameters are within normal limits
    • Occasional anemia and low hemoglobin level because of uterine bleeding
    Radiology Description
    • Magnetic resonance: small solid uterine masses with homogeneous hypointensity on T2 weighted images, and lower enhancement or cystic lesions with inner irregular solid nodules (J Comput Assist Tomogr 2015;39:499)
    Prognostic Factors
    • Benign tumor with excellent prognosis
    Case Reports
    • Surgical removal (hysterectomy or rarely simple excision)
    Gross Description
    • Solitary, small (range 0.2 - 3.5 cm, average 2.1 cm), solid nodular, well circumscribed but non encaspulated, ill defined margins, grey - white - yellow rubbery cut surface
    • Occasionally grossly inconspicuous
    • Rarely diffuse, multifocal, large or predominantly cystic (J Cancer Res Ther 2015;11:967)
    • Large multicystic tumors have a honeycomb, spongy pattern / cysts filled with serous fluid
    • Exophytic serosal component may rarely be seen
    Micro Description
    • Organized in vascular-like, gland-like, complex slit-like and cystic branching spaces; also tubules or combination of above
    • Less commonly cribriform, solid, anastomosing cords, single cells, focal papillary architecture
    • Tubules may contain basophilic secretions
    • “Thread like bridging strands” (attenuated cytoplasm that traverse the pseudovascular spaces) (Ann Diagn Pathol 2003;7:273)
    • No mitoses; no necrosis; no atypia
    • Background: hyperplastic smooth muscle
    • Stroma: edematous, inflammatory infiltrate; sometimes lymphoid follicles; lymphocytes or foamy macrophages can be found in the lumina of the tubules
    Micro Images

    Images hosted on Pathout server:

    Contributed by Ayse Ayhan, M.D., Ph.D.

    Images hosted on other servers:
    Missing Image Missing Image

    Various images

    Cytology Description
    • Flattened, cuboidal epithelioid cells: scant, pale, eosinophilic cytoplasm (may contain vacuoles) with hairy basophilic apical surface
    • Bland, round nuclei, small nucleoli
    • Occasional signet ring-like cells, which are PAS-, mucicarmine-, and may be acidic Alcian Blue+ and colloidal iron+
    • No mitotic activity / no cytological atypia
    • Occasional nests of squamoid cells
    Electron Microscopy Description
    • Abundant long slender microvilli, desmosomes, complex intercellular canalicular system, single layer basement membrane (Cancer 1970;25:171)
    Molecular / Cytogenetics Description
    • Uniform non random pattern of X chromosome inactivation, consistent with monoclonality (Hum Pathol 2016;48:88)
    Differential Diagnosis
    Additional References