Deciduoid mesothelioma: Cytologic presentation and diagnostic pitfalls

Abstract

We report two cases of malignant deciduoid mesothelioma (MDM), a very rare variant of malignant mesothelioma (MM). Case 1: An 18-year-old male with no history of asbestos exposure presented with worsening abdominal pain, anorexia, and vomiting after a motor vehicle accident. A CT scan showed small amount of ascites and abdominal mass. An exploratory laparotomy revealed multiple yellow tan, firm nodules on the peritoneum and omentum. He received palliative treatment and died 5 months after the diagnosis. Case 2: A 64-year-old female with history of asbestos exposure initially presented with abdominal distension. CT scan showed abdominal mass with a large amount of ascites. A diagnostic laparoscopy revealed multiple peritoneal nodules. She underwent several regimens of chemotherapy over a period of 69 months and is still alive to date. In both cases, features of mesothelial origin were subtle and the smears showed predominantly single cells with marked nuclear atypia. The second case also contained few two-dimensional loose cell clusters with scalloped or hobnail borders. The clusters often exhibited a pseudoacinar structure surrounding a globular extracellular material. Groups of three to four cells often formed doublets and triplets with cell-to-cell windows. Our results show that MDM may not present with the traditional cytological features described in MM and can manifest with more nuclear pleomorphism resulting in erroneous diagnosis. Recognition of the subtle mesothelial features along with the appropriate ancillary tests is essential for accurate diagnosis.

Deciduoid Mesothelioma of Peritoneum Masquerading as Peritoneal Carcinomatosis.

“…Because of the peritoneal con nement of MM and the low occurrence of metastasis, perioperative intraperitoneal chemotherapy, and cytoreductive surgery has been considered as a curative treatment option with an overall 5-year survival rate of 29-63%. [5,14] MDM behaves more aggressively than conventional epithelioid mesotheliomas. However, in many cases, this has not been proved to have a worse outcome.…”

“…[2] Deciduoid peritoneal mesothelioma has been reported in elderly patients in pleura, pericardium, and the spermatic cord in association with asbestos exposure. [4,5] The four major histological subtypes of mesothelioma are epithelioid, sarcomatoid, desmoplastic, and biphasic. Deciduoid mesothelioma is a rare subtype of epithelioid mesothelioma, in which a various range of histopathological patterns is seen.…”

Immunochemistry in the work‐up of mesothelioma and its differential diagnosis and mimickers

“…Moc‐31 staining has also been reported in a subset of squamous cell carcinoma and renal cell carcinoma 11,14,74 . SCC expresses MOC31 in 60%‐97% 11,14,75 …”

“…In one study, 16% of mesothelial cells along with macrophages and neutrophils revealed positive Ber‐EP4 staining on cytospins 78 . The expression of BerEP4 was reported as 87% to 100% in SCC cases 11,75 …”