18F-FDG PET/CT in a recurrent diffuse malignant peritoneal mesothelioma. Clin Nucl Med. 2012;37:492-494. [PMID: 22475902 DOI: 10.1097/rlu.0b013e3182478bb5]

Imaging of Malignant Pleural, Pericardial, and Peritoneal Mesothelioma

Malignant mesothelioma is a rare tumor arising from the mesothelial cells that line the pleura, pericardium, peritoneum, and tunica vaginalis. Imaging plays a primary role in the diagnosis, staging, and management of malignant mesothelioma. Multimodality imaging, including radiography, computed tomography (CT), magnetic resonance imaging (MRI), and F-18 fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT), is used in a variety of scenarios, including diagnosis, guidance for tissue sampling, staging, and reassessment of disease after therapy. CT is the primary imaging modality used in staging. MRI has superior contrast resolution compared with CT and can add value in terms of determining surgical resectability in equivocal cases. MRI can further assess the degree of local invasion, particularly into the mediastinum, chest wall, and diaphragm, for malignant pleural and pericardial mesotheliomas. FDG PET/CT plays a role in the diagnosis and staging of malignant pleural mesothelioma (MPM) and has been shown to be more accurate than CT, MRI, and PET alone in the staging of malignant pleural mesothelioma. PET/CT can also be used to target lesions for biopsy and to assess prognosis, treatment response, and tumor recurrence.

Peritoneal well-differentiated papillary mesothelioma coexisting with endometrial adenocarcinoma mimicking peritoneal carcinomatosis: A case report

OBJECTIVE

We present a rare case of well-differentiated papillary mesothelioma (WDPM) found incidentally in a 59-year-old woman with endometrial cancer.

CASE REPORT

A 59-year-old nulliparous obese woman with a past history of hypertension and diabetes mellitus presented with postmenopausal bleeding for 11 months. Two months prior to this admission, an episode of massive vaginal bleeding lasting for a day was noticed by the patient. Hysteroscopy was performed after her visit to our outpatient department. Papillary tumors with active bleeding were found in the uterine cavity. Endometrial biopsy showed adenocarcinoma, endometrioid type characterized by papillary architecture lined by columnar cells with mild nuclear pleomorphism. The patient proceeded to magnetic resonance imaging (MRI), which demonstrated a 6.4 × 5.5 × 4.9 cm intrauterine mass. Her tumor marker levels were elevated (CA 125 87.8 IU/ml, CA19-9160.54 IU/ml). The patient then underwent a staging surgery and final pathology revealed stage IA endometrial cancer. During surgery, multiple nodules were found in the peritoneum, initially considered as tumor metastasis and eventually proved to be WDPM.

CONCLUSION

In conclusion, the simultaneous occurrence of WDPM with endometrial cancer is a rare entity. Although no standardized treatment has been established, WDPMs have a relatively favorable prognosis compared to malignant mesotheliomas.

The Diagnostic Value of FDG-PET/CT for Urachal Cancer

BACKGROUND

Urachal carcinoma (UrC) is a rare malignancy that often presents at an advanced stage with metastases in up to a quarter of patients. There is no consensus on the optimal form of staging for patients with UrC. In the present study, we evaluated the diagnostic value of ¹⁸F-fluorodeoxyglucose-positron emitted tomography/computed tomography (FDG-PET/CT) for UrC.

PATIENTS AND METHODS

We evaluated 40 consecutive patients who were staged for urachal cancer between 2010 and 2020. They underwent a total of 62 FDG-PET/CTs (40 for primary staging, and 22 during follow-up), which were compared with standard-of-care contrast-enhanced CT (CECT). The metabolic detection of primary tumors, lymph node metastases (LNMs), peritoneal metastases (PMs), distant metastases (DMs), and local recurrence by FDG-PET/CT was evaluated. Sensitivity and specificity were calculated compared with CECT. Histopathology or follow-up imaging was the reference standard.

RESULTS

Of all 40 patients, 33 patients (83%) had urachal adenocarcinoma-26 (65%) with a mucinous component and 7 (17%) with invasive urothelial carcinoma. All local UrC tumors could be visualized on CT, and 80% showed increased FDG uptake. At initial staging, FDG-PET/CT detected FDG-avid LNMs, PMs, and DMs in 50%, 17%, and 25% of patients, respectively. These metastases were also visualized on CECT. During follow up, FDG-PET/CT revealed FDG-avid local recurrences that were not seen on CT in two out of eight patients (25%).

CONCLUSION

The present study demonstrates that most UrC can be visualized on FDG-PET/CT. At initial diagnosis, FDG-PET/CT does not seem to yield additional information compared with CECT; however, FDG-PET/CT may be helpful during follow-up. This is a small study, and the findings should be corroborated with larger series.

Multicystic and diffuse malignant peritoneal mesothelioma in children

BACKGROUND

Malignant and multicystic peritoneal mesotheliomas are extremely rare tumors in children, developing from mesothelial cells. No specific guidelines are available at this age.

METHODS

We performed a retrospective analysis of all identified children (< 18-year-old) treated in France from 1987 to 2017 for a diffuse malignant peritoneal mesothelioma (DMPM) or a multicystic peritoneal mesothelioma (MCPM).

RESULTS

Fourteen patients (5 males and nine females), aged 2.2 to 17.5 years, were included. The most frequent presenting symptoms were abdominal pain, ascitis, and alteration in the general condition. Eight patients had epithelioid mesothelioma, three had biphasic mesothelioma, and three had MCPM. Eight patients with DMPM diagnosis received cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC). Among them, six patients had neoadjuvant systemic chemotherapy, one patient, post-operative chemotherapy, and one patient CRS and HIPEC only. Three patients received only systemic chemotherapy. All patients with MCPM had only surgery. After a median follow-up of seven years (2-15), six patients (6/11; one death) with DMPM and two patients (two/three) with MCPM had a local and distant recurrences.

CONCLUSION

Peritoneal mesothelioma in children is a rare condition with difficult diagnosis and high risk of recurrence. Worldwide interdisciplinary collaboration and networking are mandatory to help diagnosis and provide harmonious treatment guidelines.

Malignant peritoneal mesothelioma: clinical aspects, and therapeutic perspectives

Malignant peritoneal mesothelioma (MPM) is a rare disease with a wide clinical spectrum. It arises from the peritoneal lining and commonly presents with diffuse, extensive spread throughout the abdomen and, more rarely, metastatic spread beyond the abdominal cavity. Computed tomography, magnetic resonance imaging and positron-emission tomography are important diagnostic tools used for the preoperative staging of MPM. The definitive diagnosis is based on histopathological analysis, mainly via immunohistochemistry. In this regard, paired-box gene 8 negativity represents a useful diagnostic biomarker for differentiating MPM from ovarian carcinoma. In addition, BRCA1-associated protein-1 (BAP1) loss is specific to MPM and allows it to be distinguished from both benign mesothelial lesions and ovarian serous tumors. Cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) has become an increasingly important therapeutic approach, while systemic therapies are still being developed. Histology, Ki-67, completeness of cytoreduction, age, sex, and baseline thrombocytosis are commonly used to optimize patient selection for CRS with HIPEC. Additionally, it is well recognized that, compared to other subtypes, an epithelial morphology is associated with a favorable prognosis, whereas baseline thrombocytosis predicts an aggressive biologicalbehavior. Platelets and other immunologic cytokines have been evaluated as potential novel therapeutic targets. Epigenetic modifiers, including BAP1, SETD2 and DDX3X, are crucial in mesothelial tumorigenesis and provide opportunities for targeted treatment. Overexpression of the closely interacting phosphoinositide 3-kinase (PI3K) and the mammalian target of rapamycin (mTOR) pathways appears crucial in regulation of the malignant phenotype. The use of targeted therapies with PI3K-mTOR-based inhibitors requires further clinical assessment as a novel approach.

Current management strategies for peritoneal mesothelioma

Mesothelioma of the peritoneum is a distinct entity that requires multidisciplinary care to improve oncological outcomes. In this article, we review the current management strategies discussed at the PSOGI meeting in Washington DC 2016 and provide evidence based recommendations for diagnosis and management of this disease.

Clinical presentation, diagnosis, classification and management of peritoneal mesothelioma: a review

Peritoneal mesothelioma (PM) is an uncommon but a serious, and often, fatal primary peritoneal tumour, with increasing incidence worldwide. Conventional systemic chemotherapy, generally based on experience with pleural mesothelioma, usually has disappointing results considering PM as a terminal condition. Patients usually present with non-specific symptoms of abdominal distension and pain making the diagnosis challenging. As PM is confined to the abdomen for all, or much, of its clinical course, a multimodality treatment combining cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) has emerged as a new standard of care, and has been reported to achieve promising survival outcomes and local disease control in selected patients with PM. This review updates the presentation, diagnosis, classification and treatment strategies for PM.

Peritoneal mesothelioma: the site of origin matters

The etiology, gender distribution, pathology, natural history, and treatment options for mesothelioma (MM) differ substantially depending on the site of origin. Peritoneal mesothelioma (MPeM) is a rare disease, comprising only approximately 10% to 15% of the 2,500 cases of MM diagnosed in the United States each year. Patients with MPeM are younger than patients with pleural MM, and a higher proportion, mostly women, are long-term survivors. Most MPeM is caused by asbestos exposure. Germ-line mutations of BAP1 (BRCA associated protein 1) can predispose to MM, uveal melanoma, and potentially other cancers. MPeM can be challenging to diagnose, and cytology is rarely helpful. Review by an experienced pathologist using a panel of at least two positive and two negative immunohistochemical stains is essential. The three major pathologic subtypes are epithelial, sarcomatoid, and biphasic. Most cases are epithelial; the others have a dismal prognosis. Two indolent subtypes of borderline malignant potential-well-differentiated papillary mesothelioma and benign multicystic mesothelioma-are more common in the peritoneum and are treated surgically. In highly selected patients receiving treatment at experienced referral centers, an aggressive locoregional strategy that combines cytoreductive surgery to remove all gross disease and hyperthermic intraperitoneal chemotherapy to treat residual microscopic tumors yields a 3-year survival of 60% and a median survival approaching 5 years, far better than expected from historic controls. This approach also provides durable palliation of malignant ascites in nearly all patients. Pemetrexed is the only U.S. Food and Drug Administration (FDA)-approved systemic chemotherapy for pleural MM. Largely on the basis of data from pharmaceutical registry studies, the activity of pemetrexed-based chemotherapy appears to be similar in pleural MM and MPeM.

Serendipitous discovery of peritoneal mesothelioma

We present the case of a 64-year-old patient with a history of Birt-Hogg-Dube syndrome, polycystic kidney disease treated with renal transplantation in May 2013, and multiple types of skin cancers, including malignant melanoma. He presented for lymphoscintigraphy for sentinel lymph node identification of the melanoma. Subsequent biopsy of the right axillary sentinel lymph node yielded a diagnosis of epithelial type malignant mesothelioma without a known primary tumor. Follow-up positron emission tomography with 2-deoxy-2-(fluorine-18)fluoro-D-glucose integrated with computed tomography (F-18 FDG PET/CT) demonstrated several suspicious hypermetabolic abdominal masses that were later confirmed to be epithelial-type mesothelioma via percutaneous biopsy.

Malignant Peritoneal Mesothelioma Masquerades as Peritoneal Metastasis on (18)F-FDG PET/CT Scans; a Rare Diagnosis that Should Not Be Missed

Malignant peritoneal mesothelioma (MPM) is a rare but fatal tumor. The clinical presentations and imaging findings are nonspecific and resemble various diseases, including peritoneal metastasis. Imaging findings of MPH on (18)F-(18)F-fluorodeoxyglucose ((18)F-FDG) positron emission tomography (PET)/computed tomography (CT) are diverse and not well described. We report the two cases of biopsy-proven MPH using (18)F-FDG PET/CT. In our cases, interesting disease patterns-including MPH arising from visceral peritoneal lining of kidney that suffer from polycystic disease and from the parietal peritoneum beneath the appendectomy scar-were presented. One case showed classical metastases localized within the abdominal cavity; while the other case exhibited the rare pattern of extensive multi-organ metastases. By knowing the possible variations and diagnostic pitfalls of (18)F-FDG PET/CT findings in MPM, more accurate interpretation of such mysterious cancer is attainable.

A rare case of primary paranasal sinus angiosarcoma with pulmonary metastasis detected by 18F-FDG PET/CT

The study reports a rare case of primary paranasal sinus angiosarcoma with pulmonary metastases detected by 18F-FDG PET/CT. A 29-year-old woman presented with nasal congestion and rhinorrhea for 6 months. CT scanning showed a large mass in the right maxillary sinus, which had infiltrated the surrounding tissues. Subsequent evaluation by 18F-FDG PET/CT indicated numerous nodules in the lung, in addition to the paranasal sinus mass, which exhibited elevated FDG activity. Histologic examination after nasal endoscopic biopsy confirmed the diagnosis as primary paranasal sinus angiosarcoma with pulmonary metastases.

Advances in malignant peritoneal mesothelioma

BACKGROUND

Malignant mesothelioma is a rare, insidious, and aggressive tumor arising from the mesothelial surface of pleural and peritoneal cavities, the pericardium, or the tunica vaginalis, with an increasing incidence worldwide, high misdiagnosis rate, and overall negative prognosis. A total of 20% of all cases is peritoneum in origin.

METHODS

The present study is a review of literatures focusing on the advances in epidemiology, clinical presentations, radiological features, diagnosis, misdiagnosis, management, and prognostic factors of malignant peritoneal mesothelioma (MPM) occurred in the past decades.

RESULTS

Asbestos, SV40, and radiation exposures have been demonstrated to be correlated with the pathogenesis of MPM. The main presentations are abdominal distension and pain. Computed tomography (CT), magnetic resonance imaging (MRI), and positron-emission tomography (PET) play an important role in the preoperative imaging and staging. Definitive diagnosis is made on the basis of immunohistochemistry. Prognostic factors have been identified and verified. Negative indicators include advanced age, male gender, poor performance status, non-epithelial histology, and absence of surgery. The management of MPM has evolved from single chemotherapy to multimodality treatment of cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC), chemotherapy, radiotherapy, and immunotherapy. Promising results have been achieved after a combined treatment of CRS and HIPEC, with an elevated median survival time of 29.5-92 months and a 5-year survival rate of 39-63%.

CONCLUSIONS

CRS and HIPEC represent the standard treatment strategy for selected patients with MPM, and patients with unresectable tumors can benefit from the combined treatment of chemotherapy, radiotherapy, and immunotherapy.

Advances in the management of peritoneal mesothelioma

Malignant peritoneal mesothelioma (PM) is an infrequent disease which has historically been associated with a poor prognosis. Given its long latency period and non-specific symptomatology, a diagnosis of PM can be suggested by occupational exposure history, but ultimately relies heavily on imaging and diagnostic biopsy. Early treatment options including palliative operative debulking, intraperitoneal chemotherapy, and systemic chemotherapy have marginally improved the natural course of the disease with median survival being approximately one year. The advent of cytoreduction (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) has dramatically improved survival outcomes with wide median survival estimates between 2.5 to 9 years; these studies however remain largely heterogeneous, with differing study populations, tumor biology, and specific treatment regimens. More recent investigations have explored extent of cytoreduction, repeated operative intervention, and choice of chemotherapy but have been unable to offer definitive conclusions. CRS and HIPEC remain morbid procedures with complication rates ranging between 30% to 46% in larger series. Accordingly, an increasing interest in identifying molecular targets and developing targeted therapies is emerging. Among such novel targets is sphingosine kinase 1 (SphK1) which regulates the production of sphingosine-1-phosphate, a biologically active lipid implicated in various cancers including malignant mesothelioma. The known action of specific SphK inhibitors may warrant further exploration in peritoneal disease.

Radiology-pathology conference: primary peritoneal mesothelioma

Primary peritoneal mesothelioma is a rare neoplasm which carries a dismal prognosis. These highly aggressive tumors arise from mesothelial cells lining the peritoneum and are rapidly fatal. The neoplasm is typically associated with crocidolite asbestos exposure. We present the case of a 75-year-old man with primary peritoneal mesothelioma, with invasion into the right hepatic lobe.

18F-fluoro-2-deoxy-d-glucose positron emission tomography/computed tomography fused imaging in malignant mesothelioma patients: looking from outside is not enough

Malignant mesothelioma (MM) is an uncommon neoplasm with a poor prognosis usually associated with asbestos exposure. 18F-fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET)/computed tomography (CT) has become an invaluable tool for the diagnosis, staging, and prognosis of this severe disease as it combines both anatomic and functional information in a single imaging procedure, allowing for improved management of this disease. For many authors, 18F-FDG-PET/CT is the cornerstone of the pre-therapeutic evaluation of mesothelioma patients, particularly when multimodal therapy (including extra-pleural pneumonectomy or omentectomy) is considered. However, while characteristic patterns have been reported as predictive of macroscopic pleural or peritoneal involvement, false negative findings are possible, both for pleural and peritoneal mesothelioma, during the initial diagnosis or during the patient's surveillance as illustrated by this report of three cases of suspected MM with negative PET/CT. This report highlights the limitations of PET/CT in the diagnostic evaluation of MM and the importance of histopathological confirmation by thoracoscopy and/or laparoscopy, which remain the most important diagnostic procedures in MM.