Extranodal anaplastic large cell lymphoma mimicking sarcoma: A report of an interesting case.

Lymphomas are malignancies of the lymphoid tissues involving cells of the immune system. Primary systemic anaplastic large cell lymphoma (ALCL) represents an aggressive lymphoma characterized by neoplastic proliferation of lymphoid cells with an anaplastic appearance. Large pleomorphic cells are "hallmark" cells with horseshoe-shaped or kidney-shaped nuclei and a constant expression of the CD30 molecule on all neoplastic cells. There is a vast morphological spectrum posing a challenge to pathologists in the diagnosis of ALCL. [ABSTRACT FROM AUTHOR]