Myogenic Cell Expression of Intercellular Adhesion Molecule-1 Contributes to Muscle Regeneration after Injury.

This study investigated intercellular adhesion molecule-1 (ICAM-1), a membrane protein that mediates cell-to-cell adhesion and communication, as a mechanism through which the inflammatory response facilitates muscle regeneration after injury. Toxin-induced muscle injury to tibialis anterior muscles of wild-type mice caused ICAM-1 to be expressed by a population of satellite cells/myoblasts and myofibers. Myogenic cell expression of ICAM-1 contributed to the restoration of muscle structure after injury, as regenerating myofibers were more abundant and myofiber size was larger for wild-type compared with Icam1-/- mice during 28 days of recovery. Contrastingly, restoration of muscle function after injury was similar between the genotypes. ICAM-1 facilitated the restoration of muscle structure after injury through mechanisms involving the regulation of myofiber branching, protein synthesis, and the organization of nuclei within myofibers after myogenic cell fusion. These findings provide support for a paradigm in which ICAM-1 expressed by myogenic cells after muscle injury augments their adhesive and fusogenic properties, which, in turn, facilitates regenerative and hypertrophic processes that restore structure to injured muscle.

Anaplastic Large Cell Lymphoma Presenting as Ulcerative Facial Mass: A Case Report.

Anaplastic large cell lymphoma (ALCL) is a rare form of non-Hodgkin lymphoma (NHL) that can be aggressive with rapid speed, thus mandating a timely diagnosis to optimize treatment and deter progression. NHL classically presents with lymphadenopathy and constitutional symptoms. However, ALCL can present with nonspecific cutaneous manifestations with minimal or absent constitutional symptoms. The cutaneous involvement may resemble common dermatologic conditions, delaying diagnosis. We present a case of an aggressive cutaneous ALCL lesion mimicking facial cellulitis that rapidly progressed from a small comedone to a large, exophytic mass over the course of 1 month. Prior to presentation at our institution, the patient was previously diagnosed and treated for suspected bacterial infection with no response to therapy. Core needle biopsy of the forehead lesion confirmed the diagnosis of anaplastic lymphoma kinase-negative ALCL. Chemotherapy with brentuximab vedotin, cyclophosphamide, doxorubicin, and prednisone was planned for a total of 6-8 cycles with curative intent. By cycle 5, positron emission tomography and computed tomography demonstrated response to therapy with no enlarged or metabolically active lymph nodes appreciated. Our case report highlights the importance of developing a broad differential diagnosis for ulcerative facial masses, particularly when unresponsive to antimicrobial therapies. Lymphomas should be included in the differential diagnosis of patients with rapidly growing facial lesions.