Indian Journal of Pathology and Microbiology

: 2021  |  Volume : 64  |  Issue : 2  |  Page : 415--417

Malignant pleural epithelioid mesothelioma: A mulberry mayhem

Pallavi Mishra1, Sulagna Sahoo1, Prita Pradhan1, Shreyansh Deosale2, Ranjita Panigrahi1, Krishna Padarabinda Tripathy2, Jayasree Rath1,  
1 Department of Pathology, Kalinga Institute of Medical Sciences, Bhubaneswar, Odisha, India
2 Department of Medicine, Kalinga Institute of Medical Sciences, Bhubaneswar, Odisha, India

Correspondence Address:
Prita Pradhan
Department of Pathology, Kalinga Institute of Medical Sciences, Bhubaneswar - 751 024, Odisha

How to cite this article:
Mishra P, Sahoo S, Pradhan P, Deosale S, Panigrahi R, Tripathy KP, Rath J. Malignant pleural epithelioid mesothelioma: A mulberry mayhem.Indian J Pathol Microbiol 2021;64:415-417

How to cite this URL:
Mishra P, Sahoo S, Pradhan P, Deosale S, Panigrahi R, Tripathy KP, Rath J. Malignant pleural epithelioid mesothelioma: A mulberry mayhem. Indian J Pathol Microbiol [serial online] 2021 [cited 2021 Jun 20 ];64:415-417
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Full Text

Malignant Pleural Mesothelioma (MPM) is an aggressive rare tumor with a progressive increase in its incidence.[1] It shows striking male predominance and is believed to have a strong association with asbestos exposure.[2] Limited reports on the cytologic diagnosis have been documented from India.[1],[2] So here we report in detail the cytomorphology, cell block and immunohistochemical pattern in case of epithelioid type MPM in an elderly male with no history of asbestos exposure.

A 76-year-old male,farmer by occupation, hypertensive with smoking history for 50 years, presented with cough, breathlessness, and left-sided chest pain for 4 months. Cough was associated with scanty mucoid expectoration. Breathlessness was insidious gradually progressive to a point where patient had difficulty in breathing on minimal exertion. Patient also had left sided chest pain, localized to mammary area and aggravated on inspiration or coughing. No history of fever, weight loss or hemoptysis. Respiratory system examination showed right shift of trachea and absent breath sounds on left side. Left sided pleural effusion was confirmed on chest X-ray [Figure 1]. Pleural fluid LDH was 1564 U/L (serum LDH was 634 U/L), protein 5.4 g/dl, glucose 7 mg/dl and adenosine deaminase was 17 U/L.{Figure 1}

Two pleural fluid samples were received for cytology and cell block. Total cell count was 600/ with 90% lymphocytes. Cytology revealed moderately cellular cytosmears with three dimensional cohesive morules in a hemorrhagic background [Figure 2]a, [Figure 2]b, [Figure 2]c, [Figure 2]d. These “mulberry-shaped” morules, on higher magnification, showed tightly cohesive cellular clusters arranged around a central, homogenous, dense, magenta material. Few fragments showed papillary pattern and scalloping. These cells showed enlarged pleomorphic nuclei, anisokaryosis, macronucleoli, abundant vacuolated cytoplasm, cytoplasmic blebs, and characteristic windows. Good number of mitotic figures and multinucleated giant cells were also seen. Cell block preparation showed high cellularity with eosinophilic core and surrounding tumor cells arranged in the form of morules. [Figure 2]e. Masson trichrome confirmed the collageneous nature of the core by blue color [Figure 2]f. Owing to the 3-dimensional clusters central magenta matrix material, abundant vacuolated cytoplasm, vesicular nucleus, with prominent nucleoli, a malignant effusion was considered and possibility of malignant mesothelioma was suggested. As per the guidelines, a four marker panel two favoring malignant mesothelioma and two negative for the same, was done. WT1 showed diffuse strong nuclear positivity in the tumor cells, D2-40 showed diffuse strong cytoplasmic membranous positivity in the tumor cells and TTF 1 and CEA are negative in the tumor cells [Figure 3]a [Figure 3]d. Final diagnosis of malignant mesothelioma epithelioid type was made.{Figure 2}{Figure 3}

MPM is an uncommon yet highly aggressive tumor with an incidence of 7–13 per million per year in males.[1] In large studies spanning over 25-year period in India only 15 cases were reported.[2] It commonly occurs in males.[1] It has been strongly associated with asbestos exposure but cases without it have also been documented which are attributed to genetic predilection and viral infections.[1] The mean age of presentation is 46.5 years.[2] Clinically, these patients present with pleural effusion having continuous pain, cough and breathlessness.[1],[2] Massive pleural effusion, pleural thickening with or without nodule formation may be seen.[1],[2] Radiology, pleural effusion cytology or both had a high positive predictive value.[3] Pleural fluid on cytology does help in diagnosis, but for definitive confirmation histology and immunochemistry is required.[1],[4],[5] In the present case the sample for cell block showed higher cellularity. This re-emphasizes that cell block and liquid based cytology can serve to be excellent ways to enhance cell yield.[6]

Presence of 3-dimensional cellular morules, clusters and papillary fragments along with overt malignant nuclear features favor the diagnosis of malignancy. Presence of typical intercellular “windows” indicates mesothelial origin due to the rarified ectoplasm.[6] Pap-staining slides may show a brush border and two tones staining between the endoplasm and ectoplasm. Romanowsky stains highlight the blebbing and show a pink haze near cell border. It shows cytoplasmic vacuoles which appear punched out when overlying nucleus.[6] All of these useful features were seen in the present case. There is also a notable and distinct pink extracellular matrix material has been documented in this case. The exact nature of the core matrix material have been found to be collagen in a few studies while a few articles have suggested these to be water soluble glycosaminoglycan hyaluronan.[6] In our case, based on the trichrome stain this material was found to be to collagen.

Immunocytochemistry or a cell block preparation for immunohistochemistry can help in differentiating reactive mesothelial cells from adenocarcinoma.[6] Numerous markers are available with variable sensitivity and specificity.[7] Guidelines recommend a combination of 4 markers, of which two are to confirm and two to refute the diagnosis of MPM. The former includes calretinin, CK5/6, WT-1, and podoplanin while the latter includes MOC-31, CEA-1 and TTF-1.[7]

Well-differentiated papillary mesothelioma (WDPM) in this case is an important morphologic differential. But they are rare, more frequent in peritoneum, asymptomatic, show papillae and spherules lined by bland single layer of mesothelial cells, low-grade small smoothly contoured nuclei, no nucleoli and rare mitoses.[8] MPM shows 3 histologies (a) epithelioid, which is most common, (b) sarcomatoid and (c) biphasic type, containing both epithelial and sarcomatoid (mixed) patterns. The cell block in this case was suggestive of epithelioid type.

The primary limitations in cytodiagnosis of MPM in effusion specimens are posed by low cellularity due to scanty shedding of tumor cells, associated inflammation or bleeding and lack of awareness.[6] So, to summarize appropriate cytomorphologic evaluation, cell block and ancillary techniques can help in clinching the early diagnosis while histopathology and immunohistochemistry remains gold standard.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

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Conflicts of interest

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