Pleura & peritoneum
Pleura mesothelial tumors
Mesothelioma versus adenocarcinoma

Topic Completed: 1 December 2013

Minor changes: 9 April 2021

Copyright: 2003-2021,, Inc.

PubMed Search: Pleura mesothelioma adenocarcinoma[TIAB]

Vaidehi Avadhani, M.D.
Page views in 2020: 16,070
Page views in 2021 to date: 4,149
Cite this page: Avadhani V. Mesothelioma versus adenocarcinoma. website. Accessed April 10th, 2021.
Definition / general
  • Difficult to differentiate histologically if adenocarcinoma does not produce mucin
  • Adenocarcinomas tend to have columnar morphology with more pleomorphism, nuclear molding and cellular crowding
Radiology description
  • Mesothelioma
    • Confluent nodules
    • Diffuse thick rind-like mass encasing adjacent organs
  • Adenocarcinoma / metastatic carcinoma
    • Extraserosal mass - multiple studded on the serosa
Microscopic (histologic) images

Images hosted on other servers:

Epithelioid malignant mesothelioma


Mesothelioma markers:


Alcian blue

Adenocarcinoma markers:

Monoclonal CEA

Positive stains
  • Initial workup could use 2 mesothelial markers and 2 markers for the other tumor in the differential diagnosis, on the basis of morphology
  • Use more markers if results inconclusive
  • IMIG (International Mesothelioma Interest Group) recommends 2 mesothelial markers and 2 carcinoma markers be included in the panel
  • Best positive mesothelioma markers: calretinin, CK5 or CK5/6, WT1, D2-40
  • Best positive carcinoma markers: MOC31, BerEP4, CEA and BG8 (Lewis antigen blood group)
  • Best positive lung adenocarcinoma markers: TTF1 and Napsin (Arch Pathol Lab Med 2013;137:647)

IHC stain Mesothelioma Adenocarcinoma
Cytokeratin 5 / 6 Positive Negative
Calretinin Positive Negative
D2-40 (podoplanin) Positive Negative
WT1 Positive Negative
B72.3 Negative Positive
MOC31 Negative Positive
TTF1 Negative Positive
Claudin4 Negative Positive
Special stains
  • Periodic acid Schiff after pretreatment with diastase or Alcian blue after hyaluronidase, positive, indicates neutral mucin, favors adenocarcinoma (Alcian blue without hyalurinadase is not helpful)
  • Mucicarmine should not be used as it sometimes cross reacts with hyaluronic acid
  • Histochemical methods are most useful in epithelioid mesotheliomas and not useful in nonepithelioid malignant mesotheliomas

Special stain Mesothelioma Adenocarcinoma
Alcian blue with hyaluronidase Negative Positive
PAS with diastase Negative Positive
Alcian blue Positive Positive
Pleural fluid measurements
  • High levels of hyaluronic acid levels are suggestive of mesothelioma
  • High levels of CEA are associated with adenocarcinoma
  • Intracytoplasmic neutral mucins (mucicarmine positive after hyaluronidase predigestion) is relatively specific but not sensitive for adenocarcinoma
Electron microscopy description

EM features Mesothelioma Adenocarcinoma
Apical microvilli Long and thin, no glycocalyx Shorter and have microvilli
Perinuclear tonofilament bundles Present Absent
Basal lamina Present Absent
Long desmosomes Present Absent

  • Ultrastruct Pathol 2006;30:3
  • Helpful in distinguishing mesothelioma from adenocarcinoma in well differentiated tumors
  • Not helpful in distinguishing benign / reactive from malignant mesothelial proliferations
Additional references
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