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Sarcomatoid Mesothelioma with Osteoid Differentiation

      CASE PRESENTATION

      A 75-year-old man presented with 3 months of progressive breathlessness and right-sided chest pain. Initial investigations demonstrated a pleural effusion with extensive pleural calcification and irregular pleural thickening in the right hemithorax (Fig. 1) associated with a markedly elevated serum alkaline phosphatase of 11,209 (reference range, 30–130). An isotope bone scan revealed marked tracer uptake in the right hemithorax (Fig. 2). Video-assisted thoracoscopic surgery and pleural biopsies demonstrated a malignant neoplasm consisting of plump to spindle cells with focal areas of osteoid formation (Fig. 3). The malignant cells were positive for calretinin and Cytokeratin 5/6. After clinical, radiological, and histological review at both thoracic oncology and sarcoma multidisciplinary team meetings a diagnosis of sarcomatoid mesothelioma with osteoid differentiation was made. The patient was started on palliative chemotherapy with cisplatin and pemetrexed. After three cycles of chemotherapy the patient's condition deteriorated and repeat imaging confirmed significant disease progression (Fig. 4). Chemotherapy was stopped and the patient died 4 weeks later.
      Figure thumbnail gr1
      FIGURE 1A, CXR at the time of presentation demonstrating a right pleural effusion and pleural calcification. B, Computed tomography thorax confirms the CXR findings plus irregular pleural thickening.
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      FIGURE 2Isotope bone scan demonstrating marked tracer uptake in the right hemithorax.
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      FIGURE 3Pleural biopsy confirming a malignant neoplasm with plump to spindle cells with focal areas of partly calcified osteoid.
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      FIGURE 4(A, B) Computed tomography thorax demonstrating marked progression of pleural thickening and calcification despite three cycles of palliative chemotherapy.
      This unusual subtype of malignant mesothelioma is well described in the literature.
      • Mortimer AM
      • Rowlands J
      • Murphy P
      Coarse pleural calcification in a mesothelioma patient raises the possibility of a rare tumour subtype: osteoblastic sarcomatoid mesothelioma.
      • Chave G
      • Chalabreysse L
      • Picaud G
      • et al.
      Malignant pleural mesothelioma with osteoblastic heterologous elements: CT and MR imaging findings.
      • Shiba N
      • Kusumoto M
      • Tsuta K
      • et al.
      A case of malignant pssssssleural mesothelioma with osseous and cartilaginous differentiation.
      • Demirag F
      • Unsal E
      • Tastepe I
      Biphasic malignant mesothelioma cases with osseous differentiation and long survival: a review of the literature.
      • Yousem SA
      • Hochholzer L
      Malignant mesotheliomas with osseous and cartilaginous differentiation.
      Reported survival varies from an average of 5.7 months in a series of 10 patients
      • Yousem SA
      • Hochholzer L
      Malignant mesotheliomas with osseous and cartilaginous differentiation.
      to case reports of prolonged survival ranging from 36 to 69 months.
      • Mortimer AM
      • Rowlands J
      • Murphy P
      Coarse pleural calcification in a mesothelioma patient raises the possibility of a rare tumour subtype: osteoblastic sarcomatoid mesothelioma.
      ,
      • Demirag F
      • Unsal E
      • Tastepe I
      Biphasic malignant mesothelioma cases with osseous differentiation and long survival: a review of the literature.
      This case is the first to present significant elevation of serum alkaline phosphatase, images of diffuse rather than focal pleural calcification (on follow-up computed tomography) and abnormal tracer uptake on bone scan. Any radiological features of malignant pleural disease in association with pleural calcification should raise suspicion of this rare subtype of mesothelioma.

      REFERENCES

        • Mortimer AM
        • Rowlands J
        • Murphy P
        Coarse pleural calcification in a mesothelioma patient raises the possibility of a rare tumour subtype: osteoblastic sarcomatoid mesothelioma.
        Br J Radiol. 2011; 84: 106-108
        • Chave G
        • Chalabreysse L
        • Picaud G
        • et al.
        Malignant pleural mesothelioma with osteoblastic heterologous elements: CT and MR imaging findings.
        AJR Am J Roentgenol. 2002; 178: 949-951
        • Shiba N
        • Kusumoto M
        • Tsuta K
        • et al.
        A case of malignant pssssssleural mesothelioma with osseous and cartilaginous differentiation.
        J Thorac Imaging. 2011; 26: W30-W32
        • Demirag F
        • Unsal E
        • Tastepe I
        Biphasic malignant mesothelioma cases with osseous differentiation and long survival: a review of the literature.
        Lung Cancer. 2007; 57: 233-236
        • Yousem SA
        • Hochholzer L
        Malignant mesotheliomas with osseous and cartilaginous differentiation.
        Arch Pathol Lab Med. 1987; 111: 62-66