To the best of our knowledge, fewer than 60 cases of WDPMP have been described in the literature. The reported age at diagnosis has ranged from two to 74 years old [1, 4]. Of 39 case reports we reviewed, the mean age at presentation was 44 years (median 43 years). In all, 28 patients were women and 11 patients were men [1, 2, 4, 6–12]. Symptoms at presentation included acute and chronic abdominal pain, ascites, pleural effusion, bloating, weight loss, dyspareunia, and menorrhagia [1, 4]. However, the diagnosis of WDPMP was frequently made incidentally during surgery . Only six of the patients were reported to have possible asbestos exposure, but no definitive causation has ever been described [8, 10]. Follow-up time was recorded for 37 of the 45 patient case reports we reviewed and ranged from six weeks to 29 years (median 36 months, mean 51 months) [1, 2, 4, 6–12].
The reported cases of WDPMP retain several uniting histomorphological features. Coarse papillary architecture with fibrovascular cores is the most commonly seen appearance, with occasional areas of tubulopapillary pattern [1, 4, 7–10, 12]. The papillae are lined by a simple uniform cuboidal epithelium, with little to no nuclear atypia or mitoses. The amount of fibrosis present can be variable and psammoma bodies can also be found [4, 8]. Areas of invasion are typically not seen [4, 5, 8]. Microscopic analysis of cytology from ascites can show spheroid tumor cell clusters . Classically, WDPMP exists within a spectrum of primary papillary peritoneal tumors described in women, which ranges from mesothelial hyperplasia to the more aggressive atypical diffuse mesothelioma and papillary carcinoma [1, 5]. As suggested in several previous reports, the tumor must be distinguished from its benign and malignant counterparts based on degree of cellular differentiation and atypia [1, 4, 5, 8, 12].
The case presented above is unusual in two respects. She maintained follow-up and remains alive with disease after 24 years from her initial diagnosis. This is the second longest time of follow-up reported for WDPMP. The longest follow-up was a 41-year-old woman observed for 29 years who eventually died of a pancreatic carcinoma . While many reported cases portray WDPMP as a clinically benign tumor, several case reports have described more aggressive behavior with long-term follow-up. In one case, a patient died five years following diagnosis. He was found at autopsy to have extensive retroperitoneal, anterior abdominal wall, diaphragmatic, and pericardial invasion, culminating in a large embolism of tumor cells to the pulmonary artery . A second case describes a patient who died of diffuse malignant mesothelioma approximately nine years after the diagnosis of WDPMP, suggesting a malignant transformation at some point in the clinical course . To better understand and characterize the malignant potential of this tumor, additional case reports with long-term follow-up are required.
Secondly, she received extensive chemotherapy with substantial associated morbidity, we believe on the basis of the fact that her tumor was thought originally to be an ovarian-derived tumor or primary peritoneal carcinoma, and was later thought to be a malignant peritoneal mesothelioma. Only after a repeat biopsy 19 years after her original diagnosis was the probable identity of her tumor finally understood.
Management of patients with WDPMP remains controversial. The majority of patients undergo initial exploratory laparotomy for diagnostic and cytoreductive purposes [1, 4, 8]. However this approach is contentious, given the low malignant potential of the tumor. Some authors recommend close observation or serial biopsy for surveillance . Adjuvant treatment for WDPMP also remains poorly defined and was described in only 14 of the cases that we reviewed [2, 4, 8, 10–12]. In the largest series, three patients received a combination of chemotherapy and radiation therapy, one of these with intravenous thiotepa, and two additional patients received radiation therapy alone . Of the patients who received adjuvant radiation therapy, two patients had died of radiation enteritis and intestinal obstruction at two-year and seven-year follow-up, respectively . Intraperitoneal administration of chemotherapy has been described in several case reports. One patient with simultaneous involvement of the pleural and peritoneal surfaces with ascites and pleural effusion was treated successfully with intraperitoneal, intrapleural, and intravenous carboplatin . Our patient remained disease free at four years following presentation. Four patients have received intraperitoneal hyperthermic chemoperfusion (IPHP) therapy [2, 6, 10]. Two of these patients received cisplatin and doxorubicin following optimal debulking. One patient was alive with disease at 15 months, while the other patient suffered a post-operative colobronchial fistula requiring partial colectomy and was alive 40 months later [2, 6]. Another patient received IPHP with cisplatin and mitomycin C after suboptimal debulking and died of disease progression 13 months later . A third patient with concurrent rectal carcinoma underwent a low anterior resection with omentectomy and peritonectomy and subsequent IPHP with mitomycin-C and 5-fluorouracil . Our patient had no evidence of disease at six months follow-up.
Five patients whose care reports we reviewed received intravenous chemotherapy alone, two of these with unspecified regimens [4, 8, 11]. Two patients received cisplatin and doxorubicin. One of these patients had no evidence of disease at three years, and the second patient died of disease three years later . One case described an 11-year-old girl who was treated with combination cisplatin, cyclophosphamide and maintenance lupron . She had stable diffuse peritoneal nodules at nine months. Considerable variability exists in the literature regarding the chemotherapeutic management of this tumor.