Anaplastic large-cell lymphoma (ALCL) is an uncommon type of T-cell lymphoma first reported by Stein et al 1) It is characterized by large pleomorphic CD30 (Ki-1)-expressing lymphoid blasts containing horseshoe-shaped nuclei 2).
Currently, the fourth edition of the WHO classification of tumors of hematopoietic and lymphoid tissues, published in 2008, divides systemic Anaplastic large cell lymphomas into two entities: anaplastic lymphoma kinase (ALK)-positive and ALK-negative.
Some cases lack ALK translocation correlated with a more unfavorable prognosis 3).
see also Primary central nervous system ALK-positive anaplastic large cell lymphoma
see also Primary central nervous system ALK-negative anaplastic large cell lymphoma
A case of ALCL-ALK(-) that presented as a progressive, enlarged, swollen mass on the scalp after an acute head injury in an 84-year-old man. Neither palpable lymph nodes nor any B symptoms were noted at admission. Brain computed tomography showed a hematoma in the right posterior occipital region of the scalp as the only remarkable finding. Debridement and biopsy were performed. Histologic and immunohistochemical analysis of the specimen revealed an ALCL-ALK(-) of the scalp. The lymphoma was resistant to bendamustine-containing chemotherapies, ultimately leading to the patient's death within 2 months.
This case report highlights the importance of recognizing the possibility of an ALCL presenting as a focal inflammatory swelling mass on the scalp 4).