Marco A Durán-Padilla

Follicular dendritic cell sarcoma/tumor: 2 cases of a rare tumor of difficult clinical and pathological diagnosis

The follicular dendritic cell sarcoma/tumor is a neoplasic proliferation of fusiform and ovoid cells with characteristic morphology and immunohistochemical pattern. The sarcoma/tumor term is designated due to the variability of the cytological status and, in many cases, its indeterminate clinical course. This report presents the 2 first cases seen at the Hospital General de México, OD (General Hospital of Mexico). The aim of this study is to contribute to the morphology and immunophenotype of this infrequent neoplasm, as well as discuss its differential diagnosis and clinical evolution.

Diagnosis of Thymolipoma with Fine Needle Aspiration Biopsy

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 Hassalls 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.

Primary lymphomas of the breast: a report on 5 cases studied in a period of 5 years at the Hospital General de México.

Breast lymphomas can be primary or secondary. Among the primary lymphomas, the most common histologic types are the large B-cell diffuse lymphomas and the extranodal B mucosa-associated lymphatic tissue lymphomas. We studied 5 cases of primary breast lymphoma in female patients. The criteria for the diagnosis were based on the proposal of Wiseman and Liao: (1) in the biopsy or surgical specimen, the lymphoma involves the breast parenchyma, and (2) nonsystemic disease at diagnosis. Clinical data, histologic findings, immunohistochemical reactions, treatment, and clinical follow-up were reviewed. The 5 patients were young women with average age of 27 years; the youngest was 20 years old, and the oldest was 44 years old. The right breast was the most affected, and 1 patient was HIV positive. The most common symptoms were the presence of nodes, progressive increase of volume, collateral venous network, and hemorrhagic discharge from the nipple. The clinical course was of 1 to 14 months before diagnosis. Three patients died because of central nervous system infiltration, one is still alive, and the other was lost during follow-up. Histologically, all primary breast lymphomas were large B-cell lymphomas; one had focal starry sky pattern, and the other 3 were centroblastic. All were positive to CD20 and CD79(a), 3 expressed bcl2, and 2 expressed bcl6. The proliferation index was between 60% and 80%. Primary breast lymphomas are rare. The average age of our patients was 27 years, and their clinical course was aggressive with central nervous system infiltration. The most common histologic type was the large B-cell diffuse lymphoma. Differential diagnosis must be established in the presence of poorly differentiated lobules and ductal carcinoma.