case_images: PMC10978043_01
case_images: Computed tomography (CT) head without contrast (a, b) and soft tissue neck with contrast (c) shows an enhancing mass in the left masticator space and premaxillary region, along with extension to infratemporal fossa.
case_images: cro-2024-0017-0001-536571_F01.jpg
case_images: PMC10978043_01_cro-2024-0017-0001-536571_F01.jpg
case_images: F1
case_images: Computed tomography of the head and neck revealed a well-circumscribed, enhancing mass in the left masticator space (7.5 x 8.3 cm), extending into left pharyngeal space medially and to the left infratemporal fossa (Fig. 1a-c).
case_images: Biopsy tissue revealed lymphoid tissue with large, atypical cells stained with hematoxylin and eosin stain (a). A panel of immunohistochemical strains was performed that stained positive for CD20 (b), PAX5 (c), CD5 (d), CD8 (e), and Ki-67 with a proliferation index of 100% (f). a-e are original magnification x200. Flow cytometry of atypical cells was positive for CD5 (g), CD8 (h), CD19 (g), CD20, and CD22 (h), and was kappa light chain-restricted (i).
case_images: cro-2024-0017-0001-536571_F02.jpg
case_images: PMC10978043_01_cro-2024-0017-0001-536571_F02.jpg
case_images: F2
case_images: Biopsy revealed fragments of lymphoid tissue heavily infiltrated by large, atypical cells (Fig. 2a). A panel of immunohistochemical stains was performed, and atypical cells were positive for CD20 (Fig. 2b), PAX5 (Fig. 2c), CD5 (Fig. 2d), CD8 (Fig. 2e), CD10, BCL2, BCL6, cMYC (~20%), and MUM1. The Ki-67 score showed a proliferation index of ~100% (Fig. 2f). Flow cytometry showed atypical B lymphocytes that were positive for CD5 (Fig. 2g), CD8 (Fig. 2h), CD19 (Fig. 2g), CD20, CD22 (Fig. 2h), and was kappa light chain-restricted (Fig. 2i).