| 'Pseudomesotheliomatous'
carcinomas are uncommon pathologically heterogeneous tumours with poor
prognosis.
The term 'pseudomesotheliomatous
adenocarcinoma was coined for these lesions by Harwood et al.
History of
asbestos exposure is present one study. A smoking history is present in
more than 70% cases.
By light
microscopy and immunophenotype many of the tumours mimicked malignant
mesothelioma.
Age:
Usually occurs in elderly patients.
Clinical
symptoms: Chest pain, dyspnea, cough, infiltrative pleural tumour.
The symptoms are indistinguishable from those of malignant mesothelioma.
Macroscopic
features: Thick, fleshy pleural plaques and masses that extend along
the pleura surface and encase the lung.
Microscopic
features: Pleura is infiltrated by nests and sheets of cells ;
Tumour may focally form glandular structures or tubulo-papillary
structures ; Psammoma bodies may be present ; Isolated glands may
be present in a fibrous stroma.
Histochemistry: PAS -positive diastase resistant mucin or
intracytoplasmic vacuoles are often present in the glandular lumen.
Immunohistochemistry: CEA & low molecular weight cytokeratins are
positive in almost all cases. BER-EP4 and Leu M1 may also be positive.
Misdiagnosis of
this tumour may have medico-legal implications in asbestos-related
compensation claims. |