Mediastinal pleomorphic liposarcoma diagnosed by fine needle aspiration biopsy: a case report.

BACKGROUND: Progress in radiology and pathology for diagnosing mediastinal tumors has R been made in recent decades, thanks to the use of fine needle aspiration biopsy (FNAB) guided by computed tomography, which has replaced mediastinoscopy and open biopsies. CASE: A 66-year-old male had a history o productive coughing with mucopurulent expectoration, progressive dyspnea, arthralgias, myalgias, astenia and adynamia for the previous 3 months. A CT scan and magnetic resonance imaging revealed a poorly limited tumor mass ofheterogeneous den sity in the anterior mediastinum. FNAB of the tumor mass showed malignant cells compatible with liposarcoma. CONCLUSLON: Of the several types of mesenchymal mediastinal neoplasms, liposarcoma is the most important. Many of them are seen in adults, and <10 cases have been diagnosed in children. The symptoms are related to compression of the nearby airways. Usually liposarcomas are yellow, lobed tumors without capsules that infiltrate adjacent organs and tissues. Microscopically, they have the same histologic spectrum as tumors originating in other sites. Thus, it is common to observe all the histologic varieties of soft tissue liposarcomas. The identification of lipoblasts is the key to the correct diagnosis in FNAB material.

Diagnosis of thymolipoma with fine needle aspiration biopsy. Report of a case initially misdiagnosed as liposarcoma.

BACKGROUND: Thymolipomas are the most outstanding mesenchymal mediastinal tumors although they represent only a small percentage of thymic neoplasms. Their histogenesis remains unsolved, and they are usually benign. Fine needle aspiration biopsy (FNAB) has become the method of choice for the study of mediastinal tumors, including thymolipomas. Making the correct diagnosis depends on the availability of all thymic and lipomatous components as well as on the correct application of a differential diagnosis with other lipomatous tumors. CASE: A 24-year-old woman had a 3-month history of coughing with sputum, fever, asthenia, adynamia, headaches and anemia. Physical examination revealed a bilateral pulmonary condensation syndrome. Imaging studies showed a well-defined, large mass occupying both hemithoraxes and the mediastinum. FNAB revealed an admixture of atypical adipocytes, nonneoplasic lymphoid tissue and capillaries with prominent endothelium. An initial diagnosis of well-differentiated liposarcoma was made. A 2.8-kg, encapsulated, yellowish gray mediastinal tumor was surgically removed. Mature adipose tissue intermingled with abundant thymic tissue containing numerous Hassall's corpuscles were seen histologically. Immunohistochemical markers for thymic epithelium, lymphoid tissue and adipocytes were all positive. Thymolipoma was the final diagnosis. The anemia subsided with resection of the tumor, and the patient was disease free 2.5 years after surgery. CONCLUSION: To the best of our knowledge, this is the second report of a thymolipoma studied with FNAB. The criteria for the differential diagnosis between thymolipomas and other lipomatous tumours should be kept in mind.