Soft Tissue Metastasis as Initial Manifestation of Pleural Malignant Mesothelioma

Abstract

Distant metastases of pleural malignant mesothelioma (MM) are infrequent. We report a case of MM that presented as a skeletal muscle metastasis. This type of presentation has not been previously reported. A 38-year-old male complained about a mass in his right forearm. The tumor showed the histologic pattern, immunohistochemical phenotype, and ultrastructural features of an MM. In the clinical work-up, the x-ray film and computed tomography scan demonstrated pleural effusion and diffuse pleural thickening in the right hemithorax. The pleural biopsy showed an epithelial MM. The patient died from local progression of the disease 6 months after the diagnosis. No other distant metastases were clinically evident. Our case shows the importance of including MM in the differential diagnosis of metastatic neoplasms in skeletal muscle and the usefulness of ancillary techniques in the diagnosis of mesothelial neoplasms. Int J Surg Pathol 7(1): [39][40][41][42][43][44] 1999 Pleural malignant mesothelioma (MM) usually presents with chest pain and pleural effusion. Chest roentgenograms and computed tomography (CT) scans show diffuse and irregular pleural thickening in the affected hemithorax. The tumor has a locally aggressive behavior, which accounts for most of its morbidity and mortality. Autopsy studies have revealed the presence of distant metastases, although clinically evident metastases are rare manifestations of this neoplasm [1].We report a metastatic MM presenting as a skeletal muscle mass in a patient without a previously diagnosed pleural tumor. This type of pre-

Extensive Skeletal Muscle Metastases in Malignant Pleural Mesothelioma Detected by FDG PET/CT

“…Not many but several MPM cases with distant muscle metastases have been reported in the literature. 4 5 6 11 12 13 14 15 16 17 It was also noted that the most common histological type of tumor in those cases was epithelioid MPM as observed in our patient.…”

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

“…Chest pain or dyspnea is quite common; pleuritic, bone pain, cough, and hemoptysis are less common; local tumor compression can occur, such as laryngeal nerve palsy or dysphagia; nonspecific tumor-associated symptoms can occur, such as fatigue, anorexia, and weight loss; and it is rare to see cutaneous, subcutaneous or oral lesions and neurologic symptoms—even stroke—caused by brain metastasis. 6,24,25 To the best of the authors’ knowledge, there are 18 case reports of cutaneous or subcutaneous metastases from MM 4-6,23,26-38 (Figure 6), but only 3 sarcomatoid types among them. 4-6 The data of the previous research studies indicated that the most common cutaneous or subcutaneous metastases from MM occurred on head, chest pain or dyspnea was the main symptom, about half of the patients suffered pleural effusion, they usually received chemotherapy, and 1-year-survival rate was only 20% (Figure 6).…”

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

“…The solitary mass in the back was probably via hematogenous in this case. To our knowledge, there are 18 case reports of cutaneous or subcutaneous metastases from MM [4][5][6][23][24][25][26][27][28][29][30][31][32][33][34][35][36] (Fig. 6), but only 3 sarcomatoid type of MM among them [4][5][6].…”