[Neurogenic spindle-cell tumors of the mediastinum: two cases]. / Tumeurs nerveuses à cellules fusiformes du médiastin: deux observations.

INTRODUCTION: Neurogenic tumors can develop from neural cells in any location. They are commonly found, however, in the mediastinum, most often in its posterior compartment. Neurogenic tumors can be benign or malignant. In the anterior compartment, they must be distinguished from their differential diagnoses. CASES: We report one case of a malignant peripheral nerve sheath tumor in the posterior mediastinum of a 29-year-old man and another of a schwannoma of the anterior mediastinum, in an 82-year-old woman. DISCUSSION: Neurogenic tumors of spindle-shaped cells in the mediastinum are generally benign, but can be malignant. Often asymptomatic, they are usually detected on standard pulmonary radiography, but computerized tomography is necessary, supplemented by magnetic resonance imaging, especially for posterior mediastinal tumors, to provide additional information and to assess its possible extension to adjacent structures. Radiographic, clinical, and especially histopathological features are essential for diagnosis.

[Plasmablastic lymphoma in a patient with HIV infection: an unusual case located in the skin]. / Lymphome plasmoblastique du sujet infecté par le VIH: a propos d'un cas très inhabituel de localisation cutanée.

We report the case of a plasmablastic lymphoma involving the skin in a 45 year-old HIV-positive patient. Plasmablastic lymphoma was first described in 1997 and is considered to be a diffuse large B-cell lymphoma with a unique immunophenotype and a predilection for the oral cavity. In this case, the tumor was revealed by multiple purple cutaneous nodules predominantly localized on the trunk and proximal parts of the limbs. A skin biopsy led to the diagnosis of plasmablastic lymphoma in view of the presence of a dense nodular infiltrate invading the dermis and subcutaneous fat composed of large cells that expressed neither the leucocyte common antigen nor the B- and T-cell antigens CD20 and CD3, but which showed a strong immunostaining with plasma cell marker VS38c. Most of the cells expressed Kappa light chain of immunoglobulins, they did not express Lambda light chain. In situ hybridization with EBER probe revealed detection of Epstein Barr virus in about 15 % of tumor cells. The clinical course was aggressive and rapidly fatal. Despite one cycle chemotherapy the patient died four months after presentation. HIV-associated plasmablastic lymphoma is a poor prognosis malignancy that may resist typing due to the lack of expression of commonly used lymphoid markers.