Metastasis of Sarcomatoid Malignant Mesothelioma With p16/CDKN2A Deletion Manifested as a Subcutaneous Mass in the Back: A Case Report and Review of Literature.

Sarcomatoid malignant mesothelioma (MM) is a rare and aggressive disease, and its diagnosis is challenging. A 60-year-old man presented with a recurrent subcutaneous mass in his right back after the initial resection. A chest computed tomography (CT) scan found right pleural thickening, nodular pleural thickening, pleural effusion, mediastinal, and right infraclavicular lymph nodes enlargement, which indicated a right pleura MM. Immunohistochemical stains of the resected mass showed sarcomatous atypical spindle cells, which were positive for pan-CKs (clone Anti-cytokeratin cocktail AE1/AE3), cytokeratin 5/6 (CK5/6), Wilm's tumor 1, podoplanin, vimentin and programmed death-ligand 1 (PD-L1), and negative for Napsin A, thyroid transcription factor 1, CDX 2, calretinin and desmin, and fluorescent in situ hybridization detected homozygous p16/cyclin-dependent kinase inhibitor 2A (p16/CDKN2A) deletion. The association of the chest CT features and the pathological assessment confirmed metastatic MM in the subcutaneous layer of the back. Moreover, positron emission tomography-CT showed multiple metastases in his brain. He developed massive right pleural effusion and chest tightness soon, and the mass kept growing despite local and systemic treatments. The patient die of pulmonary failure in 3 months.

Malignant mesothelioma without asbestos exposure diagnosed during EGFR-TKI treatment of lung adenocarcinoma: A case report.

Synchronous malignant mesothelioma (MM) and lung carcinoma are extremely rare in patients without a history of asbestos exposure and poses tremendous difficulties in clinical management. We report a patient without asbestos exposure diagnosed with MM during EGFR-TKI treatment of lung adenocarcinoma (LUAD), who responded to first-line chemotherapy with pemetrexed plus carboplatin and failed to subsequent systemic therapy. Clinicians should be careful about the possibility of MM comorbidity in LUAD patients whose lesions respond differently to EGFR-TKI, even in those without a history of asbestos exposure.

Distant cutaneous metastasis of malignant epithelioid mesothelioma.

Malignant mesothelioma is a locally aggressive malignancy most commonly arising from the pleural and/or peritoneal cavity. Distant cutaneous metastasis is extremely rare. Here, we describe two cases of mesothelioma metastatic to the head and neck skin. Case 1: A 64-year-old man diagnosed previously with extensive thoracic and abdominal mesothelioma, developed a rapidly growing right upper lip lesion, for which a wedge resection was performed. Case 2: A 77-year-old woman with a history of pleural mesothelioma developed a firm, mobile subcutaneous nodule on the right lateral forehead, clinically thought to represent either an epidermal inclusion cyst or a lipoma. A punch biopsy was performed. In both cases, histopathologic evaluation revealed dermal proliferation of epithelioid cells with moderate cytologic atypia and three mitotic figures per mm2 and two mitotic figures per mm2 for Cases 1 and 2, respectively. Immunohistochemical studies revealed the lesional cells to be positive for WT1, mesothelin, D2-40, CK5/6, while being negative for melanocytic and other keratinocytic markers, supporting a diagnosis of metastatic mesothelioma. Awareness of rare instances of cutaneous metastases from malignant mesothelioma is necessary to avoid possible misdiagnosis and ensure appropriate management.

Radiological evaluation of malignant pleural mesothelioma - defining distant metastatic disease.

BACKGROUND: Malignant pleural mesothelioma (MPM) is traditionally characterized by local destructive spread of the pleura and surrounding tissues. Patient outcomes in MPM with distant metastatic dissemination are lacking. METHODS: In this retrospective study, we reviewed a cohort of 164 MPM patients referred to a Phase I trials unit, aiming to describe identified metastatic sites, and correlate with clinical outcomes. RESULTS: 67% of patients were diagnosed with distant metastatic disease with a high incidence of bone (19%), visceral (14%), contralateral lung (35%) and peritoneal metastases (22%). Peritoneal metastases were more likely in epithelioid versus biphasic/ sarcomatoid MPM (p = 0.015). Overall survival was 23.8 months with no statistical difference in survival between those with distant metastases and those without. CONCLUSIONS: This report highlights the frequency of distant metastases and encourages further radiological investigations in the presence of symptoms. In particular, given the relatively high incidence of bone metastases, bone imaging should be considered in advanced MPM clinical workflow and trial protocols. The presence of distant metastases does not appear to have prognostic implications under existing treatment paradigms. This cohort of MPM patients gives an indication of patterns of metastatic spread that are likely to become prevalent as prognosis improves with emerging treatment paradigms.