Papillary mesothelioma, also referred to as well-differentiated papillary mesothelioma (WDPM), is a subtype of epithelial mesothelioma. This type isn’t definitively correlated to asbestos exposure as most patients have no history of contact with the carcinogenic material, though a handful of cases have shown a potential connection. Mostly affecting women, papillary mesothelioma is benign in most cases with a generally promising prognosis.
Where Is Papillary Mesothelioma Found?
Well-differentiated papillary mesothelioma is most commonly seen in women, but cases have also emerged in men. The majority of female patients are within reproductive ages, but there have been some reported cases in children and elderly women as well.
The three main types of mesothelioma include pleural mesothelioma, peritoneal mesothelioma and pericardial mesothelioma, based on where the cancerous growth originates. Papillary mesothelioma is most commonly found in the female peritoneum, the lining of the abdominal cavity, but has also been seen in the pleura (lung linings), tunica vaginalis (testicular linings) and other areas of the male and female reproductive system.
Diagnosis of Papillary Mesothelioma
With all forms of mesothelioma, early detection is key to ensuring the best treatment options and prognosis for the patient. Papillary mesothelioma is benign in most cases, but the potential for malignancy stresses the importance of an early diagnosis.
Symptoms of Papillary Mesothelioma
The majority of patients diagnosed with papillary mesothelioma present no symptoms. In a recent study that involved 26 female cases of papillary mesothelioma, only two patients presented symptoms. While prior results have shown many as asymptomatic, there have been some patients that have presented with the following symptoms:
- Abdominal pain
- Chronic pelvic pain
- Shortness of breath
- Swelling of the lower extremities
Observing medical history, previous exposure to asbestos and symptoms can help differentiate between papillary mesothelioma and other malignant forms, though a biopsy is key to a differential diagnosis.
Image Testing and Biopsies
Image tests, such as X-rays, CT scans, MRIs and PET scans are often one of the first steps in diagnosing mesothelioma, helping specialists to identify tumor location, sizing, progression and stage. However, the asymptomatic nature of well-differentiated papillary mesothelioma often leads to the accidental finding of mesothelioma during testing or surgeries for other conditions.
A biopsy is performed to definitively diagnose mesothelioma. A tissue sample is collected, and specialists analyze cell structure through a process known as histology. Such testing can provide insight to whether a tumor is benign or malignant, the cell type and staging.
Imaging tests and biopsies may reveal defining characteristics of papillary tumors. They are usually composed of finger-like projections (papillae) lined by single layers of flat mesothelial cells. Mutated tumor cells are often hard to distinguish from healthy cells, complicating diagnosis. Some physicians feel that the presence of psammoma bodies may help diagnose papillary tumors, but they aren’t beneficial in distinguishing mesothelioma from other cancers. Biopsies help physicians prevent a misdiagnosis, which can challenge effective mesothelioma treatment options.
- Reactive mesothelial hyperplasia
- Adenomatoid tumors
- Peritoneal carcinomatosis
- Tuberculous peritonitis
- Ovarian or peritoneal serous papillary carcinoma
- Papillary endosalpingiosis
- Malignant mesothelioma
- Malignant vascular tumors of the serous membranes
- Other low-grade serous carcinomas
Treatment of Papillary Mesothelioma
Typically benign, papillary mesothelioma is generally easy to treat. WDPM also has shown a microscopic growth pattern (metastasis), making it easier to treat than other aggressive forms, such as sarcomatoid subtypes.
The main treatment plan for papillary mesothelioma patients consists of surgical resection to remove the tumor, without a need for adjuvant therapy. In very rare cases, if WDPM is malignant, alternative treatment plans will be determined, likely consisting of a combination of surgery, chemotherapy and radiation (multimodal treatment).
With so few cases of papillary mesothelioma, specialists have struggled to come up with a standard treatment plan for the disease. In some cases, chemotherapy and radiation have been used to help shrink the tumor. However, since WDPM has low potential for malignancy, oftentimes the side effects and risks of chemotherapy and radiation outweigh the benefits, and surgery is the main course of treatment.
Potential For Recurrence
In some case reports, recurrence rates have been extremely low for patients with papillary mesothelioma. However, others have seen significantly high rates. For example, one clinicopathologic study recorded 8 cases of recurrence out of 20 patients, 4 of which had multiple recurrences.
Recurrence of papillary mesothelioma has the potential to return as malignant, and the uncertain malignant potential makes long-term follow-ups and monitoring crucial. Patients will likely then face a similar outcome to patients initially diagnosed with malignant mesothelioma, which entails a poor prognosis.
Prognosis of Papillary Mesothelioma
In general, benign cancers have a better prognosis than malignant forms. Patients ideally have a full recovery after complete surgical resection of papillary tumors. Some patients have died after going through a combination of radiation and chemotherapy, though it’s unknown whether or not the treatment combination or the tumor was the direct cause of death.
During a study of 39 reports of papillary mesothelioma, one patient died as early as one year after diagnosis, some after two years, others after 7 years, spanning all the way up to over 20 years for long-term survival rates. Varied life expectancies of WDPM bring the disease’s long-term and potentially aggressive behavior into question and further stress the importance of frequent follow-ups for patients that have faced any mesothelioma diagnosis.
If you or a loved one feel that you may have mesothelioma it’s important to seek out professional medical advice. Individual patients will decide with their doctor what the best treatment plan is, as well as determine a patient-based prognosis. Rare subtypes of mesothelioma can be difficult to understand with a lack of substantial case numbers and varying nature of the cancer, so each patient may have a different prognosis.Sources
Churg A, Allen T, Borczuk AC, et al. Well-differentiated Papillary Mesothelioma With Invasive Foci. The American Journal of Surgical Pathology. July 2014;38(7):990-998. doi: 10.1097/PAS.0000000000000200.
Clarke JM and Helft P. Long-term survival of a woman with well differentiated papillary mesothelioma of the peritoneum: a case report and review of the literature. Journal of Medicine Case Reports. October 29, 2010;4:346. doi: 10.1186/1752-1947-4-346.
Galateau-Salle F, Vignaud JM, Burke L, et al. Well-differentiated papillary mesothelioma of the pleura: a series of 24 cases. The American Journal of Surgical Pathology. April 2004;28(4):534-540.
Hoekstra, A., Riben, M., Frumovitz, M. et al. Well-Differentiated Papillary Mesothelioma of the Peritoneum: a pathological analysis and review of the literature. (2005). Gynecologic Oncology; 98(1): 161-167
Malpica A, Sant’Ambrogio, Sara, et al. Well-Differentiated Papillary Mesothelioma of the Female Peritoneum: A Clinicopathologic Study of 26 Cases. The American Journal of Surgical Pathology. January 2012;36(1):117-127. doi: 10.1097/PAS.0b013e3182354a79.