Pleural malignant deciduoid mesothelioma: Case report of a rare variant of epithelioid mesothelioma

Abstract

Malignant deciduoid mesothelioma (MDM), a rare variant of epithelioid mesothelioma, accounts for less than 5% of mesotheliomas. The term deciduoid mesothelioma was introduced by Nascimento et al. in 1994 to describe a rare variant of epithelioid mesothelioma that bears a morphological resemblance to decidua or decidual-type changes. It has an unknown etiology, and the relation with asbestos exposure remains debatable. The presence of decidual-type cells often makes the diagnosis difficult in the small biopsy specimen, especially in the peritoneal biopsy of young female patients, as they can be misdiagnosed as normal decidualized tissue. The prognosis of deciduoid mesothelioma was considered poor, but now reports suggest that the prognosis depends on the grade of the tumor. Mesothelioma is more commonly seen in older men, but deciduoid mesothelioma most often occurs in young women and is initially thought to occur only in the peritoneum of young women. Later case reports of this rare variant occurring in the pleura, the pericardium, and the tunica vaginalis of older adults are also seen. Herein we report a case of a 60-year-old male patient diagnosed with high-grade malignant deciduoid pleural mesothelioma on small biopsy, treated with four cycles of neoadjuvant chemotherapy (Pemetrexed + Carboplatin + Bevacizumab), with partial favorable response to chemotherapy underwent pleurectomy. Following this, the patient was on maintenance chemotherapy; unfortunately, he had progressive disease with adrenal and lymph node metastasis.