<prompt> A 60 year old male had a chronic history of exposure of asbestosis. He now presents with a mass in the apex of right lung. Which of the following would be seen on electron microscopy of a biopsy from the lesion?MelanosomesNeurosecretory granulesNumerous long slender microvilliDesmosomes with secretory endoplasmic reticulum  <response>: Ans. c Numerous long slender microvilliRef: Robbins 9thpg 723-724; 8thpg 733-734Prolonged asbestos exposure increases the risk of mesothelioma, which presents as a localized gray-white pleural mass.FeaturesAdenocarcinomaMalignant MesotheliomaImmunohistochemistryCarcinoembryonic antigen CEA, CD15, Ber-EP4, MUC4, thyroid transcription factor 1 TTF-1, Napsin ACalretinin, WT1, keratin 56, claudin-4,thrombomodulin, D2-40podoplanin, h-caldesmon, caveolin-1, vimentinElectron microscopyShort plump microvillilonger and more slender microvillAbout other options,A. Melanosomes: Seen in Malignant MelanomaB. Neurosecretory granules: Seen in Small Cell Carcinoma of lungD. Desmosomes with secretory endoplasmic reticulum: can suggest Adenocarcinoma 